HOME

TheInfoList



Zinc is a
chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same numbers of protons in their atomic nu ...
with the
symbol A symbol is a mark, sign, or word In linguistics, a word of a spoken language can be defined as the smallest sequence of phonemes that can be uttered in isolation with semantic, objective or pragmatics, practical meaning (linguistics), meanin ...
Zn and atomic number 30. Zinc is a slightly brittle metal at
room temperature Colloquially, room temperature is the range of air temperature Temperature is a physical quantity that expresses hot and cold. It is the manifestation of thermal energy, present in all matter, which is the source of the occurrence of heat ...
and has a silvery-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the
periodic table The periodic table, also known as the periodic table of elements, is a tabular display of the chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry ...

periodic table
. In some respects, zinc is chemically similar to
magnesium Magnesium is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same ...

magnesium
: both elements exhibit only one normal oxidation state (+2), and the Zn2+ and Mg2+
ion An ion () is a particle In the Outline of physical science, physical sciences, a particle (or corpuscule in older texts) is a small wikt:local, localized physical body, object to which can be ascribed several physical property, physical or ...
s are of similar size.The elements are from different metal groups. See periodic table. Zinc is the 24th most abundant element in Earth's crust and has five stable
isotope Isotopes are variants of a particular chemical element which differ in neutron number, and consequently in nucleon number. All isotopes of a given element have the same number of protons but different numbers of neutrons in each atom. The term ...
s. The most common zinc
ore ore – psilomelane (size: 6.7 × 5.8 × 5.1 cm) ore – galena and anglesite (size: 4.8 × 4.0 × 3.0 cm) ore (size: 7.5 × 6.1 × 4.1 cm) File:OreCartPachuca.JPG, upMinecart on display at the Historic Archive and Museum of Min ...

ore
is
sphalerite Sphalerite ((Zinc, Zn, Iron, Fe)Sulfur, S) is a mineral and ore of zinc. When the iron content is high, sphalerite is an opaque black variety called marmatite. It was discovered in 1847 by Ernst Friedrich Glocker, who named it based on the Greek w ...

sphalerite
(zinc blende), a
zinc sulfide Zinc sulfide (or zinc sulphide) is an inorganic compound with the chemical formula of ZnS. This is the main form of zinc found in nature, where it mainly occurs as the mineral sphalerite. Although this mineral is usually black because of various ...

zinc sulfide
mineral. The largest workable
lode In geology Geology (from the Ancient Greek γῆ, ''gē'' ("earth") and -λoγία, ''-logia'', ("study of", "discourse")) is an Earth science concerned with the solid Earth, the rock (geology), rocks of which it is composed, and the process ...
s are in Australia, Asia, and the United States. Zinc is refined by
froth flotation of the froth surface. Froth flotation is a process for selectively separating hydrophobic In chemistry Chemistry is the scientific discipline involved with Chemical element, elements and chemical compound, compounds composed of atoms, m ...
of the
ore ore – psilomelane (size: 6.7 × 5.8 × 5.1 cm) ore – galena and anglesite (size: 4.8 × 4.0 × 3.0 cm) ore (size: 7.5 × 6.1 × 4.1 cm) File:OreCartPachuca.JPG, upMinecart on display at the Historic Archive and Museum of Min ...

ore
,
roasting Roasting is a cooking method that uses dry heat where hot air covers the food, cooking it evenly on all sides with temperatures of at least from an open flame, oven, or other heat source. Roasting can enhance the flavor through caramelizatio ...
, and final extraction using
electricity Electricity is the set of physical phenomena associated with the presence and motion Image:Leaving Yongsan Station.jpg, 300px, Motion involves a change in position In physics, motion is the phenomenon in which an object changes its positio ...

electricity
(
electrowinning Electrowinning, also called electroextraction, is the electrodeposition of metal A metal (from Ancient Greek, Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, s ...
).
Brass Brass is an alloy of copper Copper is a chemical element with the Symbol (chemistry), symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductility, ductile metal with very high thermal conductivity, thermal a ...
, an
alloy An alloy is an admixture of metal A metal (from Ancient Greek, Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts Elec ...
of
copper Copper is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same nu ...

copper
and zinc in various proportions, was used as early as the third millennium BC in the
Aegean Aegean may refer to: *Aegean Sea *Aegean Islands *Aegean Region (geographical), Turkey *Aegean Region (statistical), Turkey *Aegean civilizations *Aegean languages, a group of ancient languages and proposed language family *Aegean Sea (theme), a n ...
area and the region which currently includes
Iraq Iraq ( ar, الْعِرَاق, translit=al-ʿIrāq; ku, عێراق, translit=Êraq), officially the Republic of Iraq ( ar, جُمْهُورِيَّة ٱلْعِرَاق '; ku, کۆماری عێراق, translit=Komarî Êraq), is a country in ...

Iraq
, the
United Arab Emirates The United Arab Emirates (UAE; ar, الإمارات العربية المتحدة ) or the Emirates ( ar, الإمارات ), is a country in Western Asia. It is located at the eastern end of the Arabian Peninsula, and shares borders with Oma ...

United Arab Emirates
,
Kalmykia Kalmykia ( rus, Калмы́кия, r=Kalmykiya, p=kɐlˈmɨkʲɪjə; xal-RU, Хальмг, ''Haľmg'' ), officially the Republic of Kalmykia,; xal-RU, Хальмг Таңһч, ''Haľmg Tañğç'' is a republic A republic ( la, res publica ...

Kalmykia
,
Turkmenistan Turkmenistan ( or ; tk, Türkmenistan, ;), also known as Turkmenia, is a sovereign country in Central Asia Central Asia is a region in Asia which stretches from the Caspian Sea in the west to China and Mongolia in the east, and from Afgh ...

Turkmenistan
and
Georgia Georgia usually refers to: * Georgia (country) Georgia ( ka, საქართველო; ''Sakartvelo''; ) is a country located at the intersection of Eastern Europe Eastern Europe is the region of the European continent between Wester ...
. In the second millennium BC it was used in the regions currently including
West India Western India is a loosely defined region of India consisting of its western part. The Ministry of Home Affairs in its Western Zonal Council Administrative division Administrative division, administrative unitArticle 3(1). , country sub ...
,
Uzbekistan Uzbekistan (, ; uz, Ozbekiston, ), officially the Republic of Uzbekistan ( uz, Ozbekiston Respublikasi), is a landlocked country A country is a distinct territory, territorial body or political entity. It is often referred to as the land ...

Uzbekistan
,
Iran Iran ( fa, ایران ), also called Persia and officially the Islamic Republic of Iran ( fa, جمهوری اسلامی ایران ), is a country in Western Asia. It is bordered to the northwest by Armenia and Azerbaijan, to the north ...

Iran
,
Syria Syria ( ar, سُورِيَا, ''Sūriyā''), officially the Syrian Arab Republic ( ar, ٱلْجُمْهُورِيَّةُ ٱلْعَرَبِيَّةُ ٱلسُّورِيَّةُ, al-Jumhūrīyah al-ʻArabīyah as-Sūrīyah), is a country in ...

Syria
, Iraq, and
Israel Israel (; he, יִשְׂרָאֵל, translit=Yīsrāʾēl; ar, إِسْرَائِيل, translit=ʾIsrāʾīl), officially the State of Israel ( he, מְדִינַת יִשְׂרָאֵל, label=none, translit=Medīnat Yīsrāʾēl; ), is a ...

Israel
. Zinc
metal A metal (from Ancient Greek, Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts Electrical resistivity and conductivity, el ...

metal
was not produced on a large scale until the 12th century in India, though it was known to the ancient Romans and Greeks. The mines of
Rajasthan Rajasthan ( ; literally, "Land of Kings") is a States and union territories of India, state in northern India. The state covers an area of or 10.4 percent of the total geographical area of India. It is the List of states and union territories ...

Rajasthan
have given definite evidence of zinc production going back to the 6th century BC. To date, the oldest evidence of pure zinc comes from Zawar, in Rajasthan, as early as the 9th century AD when a distillation process was employed to make pure zinc.
Alchemists File:Aurora consurgens zurich 044 f-21v-44 dragon-pot.jpg, Depiction of Ouroboros from the alchemical treatise ''Aurora consurgens'' (15th century), Zentralbibliothek Zürich, Switzerland Alchemy (from Arabic: ''al-kīmiyā''; from Ancient Gree ...
burned zinc in air to form what they called " philosopher's wool" or "white snow". The element was probably named by the alchemist
Paracelsus Paracelsus (; c. 1493 – 24 September 1541), born Theophrastus von Hohenheim (full name Philippus Aureolus Theophrastus Bombastus von Hohenheim), was a Swiss physician, alchemist Depiction of Ouroboros from the alchemical treatise ''Aurora c ...

Paracelsus
after the German word ''Zinke'' (prong, tooth). German chemist
Andreas Sigismund Marggraf Andreas Sigismund Marggraf (; 3 March 1709 – 7 August 1782) was a German chemist A chemist (from Greek ''chēm(ía)'' alchemy; replacing ''chymist'' from Medieval Latin ''alchemist'') is a scientist A scientist is a person who conducts Scie ...
is credited with discovering pure metallic zinc in 1746. Work by
Luigi Galvani Luigi Galvani (, also ; ; la, Aloysius Galvanus; 9 September 1737 – 4 December 1798) was an Italian physician, physicist, biologist and philosopher, who discovered animal electricity. He is recognized as the pioneer of bioelectromagnetics. In ...
and
Alessandro Volta Alessandro Giuseppe Antonio Anastasio Volta (, ; 18 February 1745 – 5 March 1827) was an Italian physicist, chemist, and pioneer of electricity Electricity is the set of physical phenomena associated with the presence and motion ...
uncovered the electrochemical properties of zinc by 1800.
Corrosion Corrosion is a natural process that converts a refined metal into a more chemically stable form such as oxide of rutile Rutile is a mineral composed primarily of titanium dioxide (TiO2), and is the most common natural form of TiO2. Other rare ...
-resistant zinc plating of iron (
hot-dip galvanizing Hot-dip galvanization is a form of galvanization Galvanization or galvanizing ( also spelled galvanisation or galvanising) is the process of applying a protective zinc Zinc is a chemical element with the Symbol (chemistry), symbol Zn a ...
) is the major application for zinc. Other applications are in electrical
batteries Battery may refer to: Energy source * Electric battery, an electrochemical device to provide electrical power ** Automotive battery, a device to provide power to certain functions of an automobile ** List of battery types * Energy storage, inclu ...
, small non-structural castings, and alloys such as
brass Brass is an alloy of copper Copper is a chemical element with the Symbol (chemistry), symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductility, ductile metal with very high thermal conductivity, thermal a ...
. A variety of zinc compounds are commonly used, such as
zinc carbonate Smithsonite, also known as turkey fat or zinc spar, is zinc carbonate ( Zn C O3), a mineral ore of zinc. Historically, smithsonite was identified with hemimorphite before it was realized that they were two different minerals. The two minerals are ve ...

zinc carbonate
and (as dietary supplements),
zinc chloride Zinc chloride is the name of chemical compounds with the formula ZnCl2 and its hydrates. Zinc Zinc is a chemical element with the Symbol (chemistry), symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and ha ...

zinc chloride
(in deodorants),
zinc pyrithione Zinc pyrithione (or pyrithione zinc) is a coordination complex of zinc Zinc is a chemical element with the Symbol (chemistry), symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a silvery-greyish app ...
(anti-
dandruff Dandruff is a skin condition that mainly affects the scalp. Symptoms include flaking and sometimes mild itchiness. It can result in social or self-esteem problems. A more severe form of the condition, which includes inflammation of the skin, ...
shampoos),
zinc sulfide Zinc sulfide (or zinc sulphide) is an inorganic compound with the chemical formula of ZnS. This is the main form of zinc found in nature, where it mainly occurs as the mineral sphalerite. Although this mineral is usually black because of various ...

zinc sulfide
(in luminescent paints), and
dimethylzinc Dimethylzinc, also known as Zinc methyl, DMZ, or DMZn is a colorless volatile liquid Zn(CH3)2, formed by the action of methyl iodide on zinc at elevated temperature or on zinc sodium alloy. :2Zn + 2CH3I → Zn(CH3)2 + ZnI2 The sodium assists the ...
or
diethylzinc Diethylzinc (C2H5)2Zn, or DEZ, is a highly pyrophoric and reactive organozinc compound consisting of a zinc Zinc is a chemical element with the Symbol (chemistry), symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room tempe ...
in the organic laboratory. Zinc is an
essential mineral In the context of nutrition, a mineral is a chemical element required as an essential nutrient by organisms to perform functions necessary for life. However, the four major structural elements in the human body by weight (oxygen, hydrogen, carbon, ...
, including to prenatal and postnatal development.
Zinc deficiency Zinc deficiency is defined either as insufficient zinc Zinc is a chemical element with the Symbol (chemistry), symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a silvery-greyish appearance when oxi ...
affects about two billion people in the developing world and is associated with many diseases. In children, deficiency causes growth retardation, delayed sexual maturation, infection susceptibility, and
diarrhea Diarrhea, also spelled diarrhoea, is the condition of having at least three loose, liquid, or watery bowel movements each day. It often lasts for a few days and can result in dehydration In physiology, dehydration is a lack of total body ...
.
Enzyme Enzymes () are proteins that act as biological catalysts (biocatalysts). Catalysts accelerate chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates int ...

Enzyme
s with a zinc atom in the reactive center are widespread in biochemistry, such as
alcohol dehydrogenase Alcohol dehydrogenases (ADH) () are a group of dehydrogenase A dehydrogenase is an enzyme Enzymes () are proteins that act as biological catalysts (biocatalysts). Catalysts accelerate chemical reactions. The molecules upon which enzymes may ...

alcohol dehydrogenase
in humans. Consumption of excess zinc may cause
ataxia Ataxia is a neurological sign consisting of lack of voluntary coordination of muscle movements that can include gait abnormality, speech changes, and abnormalities in eye movements. Ataxia is a clinical manifestation indicating dysfunction of ...
,
lethargy Lethargy is a state of tiredness, weariness, fatigue, or lack of energy. It can be accompanied by depression, decreased motivation, or apathy. Lethargy can be a normal response to inadequate sleep, overexertion, overworking, stress, lack of exerc ...
, and copper deficiency.


Characteristics


Physical properties

Zinc is a bluish-white, lustrous,
diamagnetic Diamagnetic materials are repelled by a magnetic field A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experie ...
metal, though most common commercial grades of the metal have a dull finish. It is somewhat less dense than
iron Iron () is a chemical element with Symbol (chemistry), symbol Fe (from la, Wikt:ferrum, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 element, group 8 of the periodic table. It is, Abundance ...

iron
and has a hexagonal
crystal structure In crystallography Crystallography is the experimental science of determining the arrangement of atoms in crystalline solids (see crystal structure). The word "crystallography" is derived from the Greek words ''crystallon'' "cold drop, frozen ...
, with a distorted form of hexagonal close packing, in which each atom has six nearest neighbors (at 265.9 pm) in its own plane and six others at a greater distance of 290.6 pm. The metal is hard and brittle at most temperatures but becomes malleable between 100 and 150 °C. Above 210 °C, the metal becomes brittle again and can be pulverized by beating. Zinc is a fair conductor of electricity. For a metal, zinc has relatively low melting (419.5 °C) and boiling points (907 °C). The melting point is the lowest of all the
d-block A block of the periodic table The periodic table, also known as the periodic table of elements, is a tabular display of the chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the c ...
metals aside from
mercury Mercury usually refers to: * Mercury (planet) Mercury is the smallest planet in the Solar System and the closest to the Sun. Its orbit around the Sun takes 87.97 Earth days, the shortest of all the Sun's planets. It is named after the Roman g ...

mercury
and
cadmium Cadmium is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same num ...
; for this reason among others, zinc, cadmium, and mercury are often not considered to be
transition metal In chemistry, the term transition metal (or transition element) has three possible definitions: * The IUPAC The International Union of Pure and Applied Chemistry (IUPAC ) is an international federation of National Adhering Organizations tha ...
s like the rest of the d-block metals. Many
alloy An alloy is an admixture of metal A metal (from Ancient Greek, Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts Elec ...
s contain zinc, including brass. Other metals long known to form binary alloys with zinc are
aluminium Aluminium (aluminum in American American(s) may refer to: * American, something of, from, or related to the United States of America, commonly known as the United States The United States of America (USA), commonly known as the Unit ...
,
antimony Antimony is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same ...
,
bismuth Bismuth is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same numbe ...
,
gold Gold is a chemical element with the Symbol (chemistry), symbol Au (from la, aurum) and atomic number 79, making it one of the higher atomic number elements that occur naturally. In a pure form, it is a brightness, bright, slightly reddish yel ...

gold
,
iron Iron () is a chemical element with Symbol (chemistry), symbol Fe (from la, Wikt:ferrum, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 element, group 8 of the periodic table. It is, Abundance ...

iron
,
lead Lead is a chemical element with the Symbol (chemistry), symbol Pb (from the Latin ) and atomic number 82. It is a heavy metals, heavy metal that is density, denser than most common materials. Lead is Mohs scale of mineral hardness#Intermediate h ...

lead
,
mercury Mercury usually refers to: * Mercury (planet) Mercury is the smallest planet in the Solar System and the closest to the Sun. Its orbit around the Sun takes 87.97 Earth days, the shortest of all the Sun's planets. It is named after the Roman g ...

mercury
,
silver Silver is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same n ...

silver
,
tin Tin is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same numbers ...

tin
,
magnesium Magnesium is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same ...

magnesium
,
cobalt Cobalt is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same numbe ...
,
nickel Nickel is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same numb ...

nickel
,
tellurium Tellurium is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same num ...

tellurium
, and
sodium Sodium is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same num ...

sodium
. Although neither zinc nor
zirconium Zirconium is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same num ...

zirconium
is
ferromagnetic Ferromagnetism is the basic mechanism by which certain materials (such as iron Iron () is a chemical element with Symbol (chemistry), symbol Fe (from la, Wikt:ferrum, ferrum) and atomic number 26. It is a metal that belongs to the first tra ...
, their alloy exhibits ferromagnetism below 35 .


Occurrence

Zinc makes up about 75  ppm (0.0075%) of
Earth's crust 350px, Plates in the crust of Earth Earth's crust is a thin shell on the outside of Earth, accounting for less than 1% of Earth's volume. It is the top component of the lithosphere, a division of Earth's layers that includes the Crust (geology), ...
, making it the 24th most abundant element. Typical background concentrations of zinc do not exceed 1 μg/m3 in the atmosphere; 300 mg/kg in soil; 100 mg/kg in vegetation; 20 μg/L in freshwater and 5 μg/L in seawater. The element is normally found in association with other
base metal A base metal is a common and inexpensive metal A metal (from Ancient Greek, Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conduc ...
s such as
copper Copper is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same nu ...

copper
and
lead Lead is a chemical element with the Symbol (chemistry), symbol Pb (from the Latin ) and atomic number 82. It is a heavy metals, heavy metal that is density, denser than most common materials. Lead is Mohs scale of mineral hardness#Intermediate h ...

lead
in
ore ore – psilomelane (size: 6.7 × 5.8 × 5.1 cm) ore – galena and anglesite (size: 4.8 × 4.0 × 3.0 cm) ore (size: 7.5 × 6.1 × 4.1 cm) File:OreCartPachuca.JPG, upMinecart on display at the Historic Archive and Museum of Min ...

ore
s. Zinc is a chalcophile, meaning the element is more likely to be found in minerals together with
sulfur Sulfur (in nontechnical British English: sulphur) is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consis ...

sulfur
and other heavy
chalcogen The chalcogens () are the chemical elements in group (periodic table), group 16 of the periodic table. This group is also known as the oxygen family. It consists of the elements oxygen (O), sulfur (S), selenium (Se), tellurium (Te), and the Radioa ...
s, rather than with the light chalcogen
oxygen Oxygen is the chemical element with the chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen Group (periodic table), group in the periodic table, a highly Chemical reaction, reactive nonmetal, and an oxidizing a ...

oxygen
or with non-chalcogen electronegative elements such as the
halogen The halogens () are a group in the periodic table consisting of five chemically related elements: fluorine Fluorine is a chemical element with the Chemical symbol, symbol F and atomic number 9. It is the lightest halogen and exists at Standar ...

halogen
s.
Sulfide Sulfide (British English British English (BrE) is the standard dialect of the English language English is a West Germanic languages, West Germanic language first spoken in History of Anglo-Saxon England, early medieval England, whi ...

Sulfide
s formed as the crust solidified under the conditions of the early Earth's atmosphere.
Sphalerite Sphalerite ((Zinc, Zn, Iron, Fe)Sulfur, S) is a mineral and ore of zinc. When the iron content is high, sphalerite is an opaque black variety called marmatite. It was discovered in 1847 by Ernst Friedrich Glocker, who named it based on the Greek w ...

Sphalerite
, which is a form of zinc sulfide, is the most heavily mined zinc-containing ore because its concentrate contains 60–62% zinc. Other source minerals for zinc include
smithsonite Smithsonite, also known as turkey fat or zinc spar, is zinc carbonate ( Zn C O3), a mineral ore of zinc. Historically, smithsonite was identified with hemimorphite before it was realized that they were two different minerals. The two minerals are ve ...

smithsonite
(zinc
carbonate In chemistry, a carbonate is a salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of Salt (chemistry), salts; salt in its natural form as a crystallinity, crystalline min ...
),
hemimorphite Hemimorphite is the chemical compound Zinc, Zn4(Pyrosilicate, Si2O7)(Hydroxide, OH)2Water of crystallization, ·H2O, a component of mineral Calamine (mineral), calamine. It is a silicate mineral which, together with smithsonite (ZnCO3), has been h ...

hemimorphite
(zinc
silicate In chemistry Chemistry is the scientific discipline involved with Chemical element, elements and chemical compound, compounds composed of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they unde ...
),
wurtzite Wurtzite is a zinc and iron sulfide mineral with the chemical formula , a less frequently encountered Polymorphism (materials science), structural polymorph form of sphalerite. The iron content is variable up to eight percent.Palache, Charles, Harr ...

wurtzite
(another zinc sulfide), and sometimes hydrozincite (basic
zinc carbonate Smithsonite, also known as turkey fat or zinc spar, is zinc carbonate ( Zn C O3), a mineral ore of zinc. Historically, smithsonite was identified with hemimorphite before it was realized that they were two different minerals. The two minerals are ve ...

zinc carbonate
). With the exception of wurtzite, all these other minerals were formed by weathering of the primordial zinc sulfides. Identified world zinc resources total about 1.9–2.8 billion
tonne The tonne ( or ; symbol: t) is a metric unit of mass equal to 1,000 kilogram The kilogram (also kilogramme) is the base unit of mass in the International System of Units (SI), the current metric system, having the unit symbol kg. I ...
s. Large deposits are in Australia, Canada and the United States, with the largest reserves in
Iran Iran ( fa, ایران ), also called Persia and officially the Islamic Republic of Iran ( fa, جمهوری اسلامی ایران ), is a country in Western Asia. It is bordered to the northwest by Armenia and Azerbaijan, to the north ...

Iran
. The most recent estimate of reserve base for zinc (meets specified minimum physical criteria related to current mining and production practices) was made in 2009 and calculated to be roughly 480 Mt. Zinc reserves, on the other hand, are geologically identified ore bodies whose suitability for recovery is economically based (location, grade, quality, and quantity) at the time of determination. Since exploration and mine development is an ongoing process, the amount of zinc reserves is not a fixed number and sustainability of zinc ore supplies cannot be judged by simply extrapolating the combined mine life of today's zinc mines. This concept is well supported by data from the United States Geological Survey (USGS), which illustrates that although refined zinc production increased 80% between 1990 and 2010, the reserve lifetime for zinc has remained unchanged. About 346 million tonnes have been extracted throughout history to 2002, and scholars have estimated that about 109–305 million tonnes are in use.


Isotopes

Five stable
isotope Isotopes are variants of a particular chemical element which differ in neutron number, and consequently in nucleon number. All isotopes of a given element have the same number of protons but different numbers of neutrons in each atom. The term ...
s of zinc occur in nature, with 64Zn being the most abundant isotope (49.17%
natural abundance In physics Physics (from grc, φυσική (ἐπιστήμη), physikḗ (epistḗmē), knowledge of nature, from ''phýsis'' 'nature'), , is the natural science that studies matter, its Motion (physics), motion and behavior through Spa ...

natural abundance
). The other isotopes found in nature are (27.73%), (4.04%), (18.45%), and (0.61%). Several dozen
radioisotope A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is an atom that has excess nuclear energy, making it unstable. This excess energy can be used in one of three ways: emitted from the nucleus as gamma radiation; transferred ...
s have been characterized. , which has a half-life of 243.66 days, is the least active radioisotope, followed by with a half-life of 46.5 hours. Zinc has 10
nuclear isomer A nuclear isomer is a metastable state of an atomic nucleus, in which one or more nucleon In chemistry Chemistry is the scientific discipline involved with Chemical element, elements and chemical compound, compounds composed of atoms, mol ...
s. 69mZn has the longest half-life, 13.76 h. The superscript ''m'' indicates a
metastable In physics Physics (from grc, φυσική (ἐπιστήμη), physikḗ (epistḗmē), knowledge of nature, from ''phýsis'' 'nature'), , is the natural science that studies matter, its Motion (physics), motion and behavior through ...

metastable
isotope. The nucleus of a metastable isotope is in an
excited state In quantum mechanics Quantum mechanics is a fundamental Scientific theory, theory in physics that provides a description of the physical properties of nature at the scale of atoms and subatomic particles. It is the foundation of all quantu ...
and will return to the
ground state The ground state of a quantum mechanics, quantum-mechanical system is its lowest-energy stationary state, state; the energy of the ground state is known as the zero-point energy of the system. An excited state is any state with energy greater than ...
by emitting a
photon The photon ( el, φῶς, phōs, light) is a type of elementary particle In particle physics, an elementary particle or fundamental particle is a subatomic particle that is not composed of other particles. Particles currently thought to be eleme ...

photon
in the form of a
gamma ray A gamma ray, or gamma radiation (symbol γ or \gamma), is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves and so imparts the hi ...
. has three excited metastable states and has two. The isotopes , , and each have only one excited metastable state. The most common
decay mode Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration or nuclear disintegration) is the process by which an unstable atomic nucleus The atomic nucleus is the small, dense region consisting of proton A ...
of a
radioisotope A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is an atom that has excess nuclear energy, making it unstable. This excess energy can be used in one of three ways: emitted from the nucleus as gamma radiation; transferred ...
of zinc with a
mass number The mass number (symbol ''A'', from the German word ''Atomgewicht'' tomic weight, also called atomic mass number or nucleon number, is the total number of proton A proton is a subatomic particle, symbol or , with a positive electric charge of ...
lower than 66 is
electron capture Electron capture (K-electron capture, also K-capture, or L-electron capture, L-capture) is a process in which the proton-rich nucleus of an electrically neutral atom absorbs an inner atomic electron, usually from the K or L electron shells. Th ...

electron capture
. The
decay product The decay chain from lead-212 down to lead-208, showing the intermediate decay products. In nuclear physics Nuclear physics is the field of physics that studies atomic nuclei and their constituents and interactions. Other forms of nuclear mat ...
resulting from electron capture is an isotope of copper. : + → The most common decay mode of a radioisotope of zinc with mass number higher than 66 is
beta decay (the accompanying antineutrino is omitted). The inset shows beta decay of a free neutron. Neither of these depictions shows the intermediate virtual boson. In nuclear physics, beta decay (''β''-decay) is a type of radioactive decay Rad ...
), which produces an isotope of
gallium Gallium is a chemical element with the Symbol (chemistry), symbol Ga and atomic number 31. Discovered by France, French chemist Paul-Émile Lecoq de Boisbaudran in 1875, Gallium is in boron group, group 13 of the periodic table and is s ...

gallium
. : → + +


Compounds and chemistry


Reactivity

Zinc has an
electron configuration In atomic physics and quantum chemistry, the electron configuration is the distribution of electrons of an atom An atom is the smallest unit of ordinary matter In classical physics and general chemistry, matter is any substance tha ...
of d104s2 and is a member of the group 12 of the
periodic table The periodic table, also known as the periodic table of elements, is a tabular display of the chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry ...

periodic table
. It is a moderately reactive
metal A metal (from Ancient Greek, Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts Electrical resistivity and conductivity, el ...

metal
and strong
reducing agent A reducing agent (also called a reductant, reducer, or electron donor) is an element or compound that loses or "donates" an electron The electron is a subatomic particle In physical sciences, subatomic particles are smaller than atom ...
. The surface of the pure metal
tarnish Tarnish is a thin layer of corrosion that forms over copper Copper is a chemical element with the Symbol (chemistry), symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductility, ductile metal with very high the ...
es quickly, eventually forming a protective passivating layer of the basic
zinc carbonate Smithsonite, also known as turkey fat or zinc spar, is zinc carbonate ( Zn C O3), a mineral ore of zinc. Historically, smithsonite was identified with hemimorphite before it was realized that they were two different minerals. The two minerals are ve ...
, , by reaction with atmospheric
carbon dioxide Carbon dioxide (chemical formula ) is a colorless gas with a density about 53% higher than that of dry air. Carbon dioxide molecules consist of a carbon atom covalent bond, covalently double bonded to two oxygen atoms. It occurs naturally in At ...

carbon dioxide
. Zinc burns in air with a bright bluish-green flame, giving off fumes of
zinc oxide Zinc oxide is an inorganic compound with the Chemical formula, formula . ZnO is a white powder that is insoluble in water. It is used as an additive in numerous materials and products including cosmetics, food supplements, rubbers, plastics, cerami ...

zinc oxide
. Zinc reacts readily with
acid An acid is a molecule or ion An ion () is a particle In the Outline of physical science, physical sciences, a particle (or corpuscule in older texts) is a small wikt:local, localized physical body, object to which can be ascribed se ...
s,
alkali In chemistry Chemistry is the scientific discipline involved with Chemical element, elements and chemical compound, compounds composed of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they ...
s and other non-metals. Extremely pure zinc reacts only slowly at
room temperature Colloquially, room temperature is the range of air temperature Temperature is a physical quantity that expresses hot and cold. It is the manifestation of thermal energy, present in all matter, which is the source of the occurrence of heat ...
with acids. Strong acids, such as or
sulfuric acid Sulfuric acid (American spelling Despite the various English dialects spoken from country to country and within different regions of the same country, there are only slight regional variations in English orthography English orthograp ...

sulfuric acid
, can remove the passivating layer and the subsequent reaction with the acid releases hydrogen gas. The chemistry of zinc is dominated by the +2 oxidation state. When compounds in this oxidation state are formed, the outer
shell Shell may refer to: Architecture and design * Shell (structure)A shell is a type of structural element which is characterized by its geometry, being a three-dimensional solid whose thickness is very small when compared with other dimensions, and i ...
''s'' electrons are lost, yielding a bare zinc ion with the electronic configuration d10. In aqueous solution an octahedral complex, is the predominant species. The
volatilization Volatilization is the process whereby a dissolved sample is vaporised. In atomic spectroscopy Atomic spectroscopy is the study of the electromagnetic radiation absorbed and emitted by atoms. Since unique elements have characteristic (signature) spe ...
of zinc in combination with zinc chloride at temperatures above 285 °C indicates the formation of , a zinc compound with a +1 oxidation state. No compounds of zinc in positive oxidation states other than +1 or +2 are known. Calculations indicate that a zinc compound with the oxidation state of +4 is unlikely to exist. Zn(III) is predicted to exist in the presence of strongly electronegative trianions; however, there exists some doubt around this possibility. But in 2021 another compound was reported with more evidence that had the oxidation state of +3 with the formula ZnBeB11(CN)12. Zinc chemistry is similar to the chemistry of the late first-row transition metals,
nickel Nickel is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same numb ...

nickel
and copper, though it has a filled d-shell and compounds are
diamagnetic Diamagnetic materials are repelled by a magnetic field A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experie ...
and mostly colorless. The ionic radii of zinc and magnesium happen to be nearly identical. Because of this some of the equivalent salts have the same
crystal structure In crystallography Crystallography is the experimental science of determining the arrangement of atoms in crystalline solids (see crystal structure). The word "crystallography" is derived from the Greek words ''crystallon'' "cold drop, frozen ...
, and in other circumstances where ionic radius is a determining factor, the chemistry of zinc has much in common with that of magnesium. In other respects, there is little similarity with the late first-row transition metals. Zinc tends to form bonds with a greater degree of covalency and much more stable complexes with - and - donors. Complexes of zinc are mostly 4- or 6-
coordinate In geometry Geometry (from the grc, γεωμετρία; ''wikt:γῆ, geo-'' "earth", ''wikt:μέτρον, -metron'' "measurement") is, with arithmetic, one of the oldest branches of mathematics. It is concerned with properties of space t ...
, although 5-coordinate complexes are known.


Zinc(I) compounds

Zinc(I) compounds are rare and need bulky ligands to stabilize the low oxidation state. Most zinc(I) compounds contain formally the [Zn2]2+ core, which is analogous to the [Hg2]2+ dimeric cation present in
mercury Mercury usually refers to: * Mercury (planet) Mercury is the smallest planet in the Solar System and the closest to the Sun. Its orbit around the Sun takes 87.97 Earth days, the shortest of all the Sun's planets. It is named after the Roman g ...

mercury
(I) compounds. The diamagnetism, diamagnetic nature of the ion confirms its dimeric structure. The first zinc(I) compound containing the Zn–Zn bond, Decamethyldizincocene, (η5-C5Me5)2Zn2, is also the first metallocene, dimetallocene. The [Zn2]2+ ion rapidly disproportionation, disproportionates into zinc metal and zinc(II), and has been obtained only a yellow glass only by cooling a solution of metallic zinc in molten ZnCl2.


Zinc(II) compounds

Binary compounds of zinc are known for most of the metalloids and all the nonmetals except the noble gases. The oxide zinc oxide, ZnO is a white powder that is nearly insoluble in neutral aqueous solutions, but is amphoteric, dissolving in both strong basic and acidic solutions. The other
chalcogen The chalcogens () are the chemical elements in group (periodic table), group 16 of the periodic table. This group is also known as the oxygen family. It consists of the elements oxygen (O), sulfur (S), selenium (Se), tellurium (Te), and the Radioa ...
ides (zinc sulfide, ZnS, zinc selenide, ZnSe, and zinc telluride, ZnTe) have varied applications in electronics and optics. Pnictogenides (Zinc nitride, , zinc phosphide, , zinc arsenide, and zinc antimonide, ), the peroxide (zinc peroxide, ), the hydride (zinc hydride, ), and the carbide () are also known. Of the four halides, zinc fluoride, has the most ionic character, while the others (zinc chloride, , zinc bromide, , and zinc iodide, ) have relatively low melting points and are considered to have more covalent character. In weak basic solutions containing ions, the hydroxide Zinc hydroxide, forms as a white precipitate. In stronger alkaline solutions, this hydroxide is dissolved to form zincates (zincate, ). The nitrate Zinc nitrate, , chlorate Zinc chlorate, , sulfate Zinc sulfate, , phosphate Zinc phosphate, , molybdate Zinc molybdate, , cyanide Zinc cyanide, , arsenite , arsenate and the chromate Zinc chromate, (one of the few colored zinc compounds) are a few examples of other common inorganic compounds of zinc. One of the simplest examples of an organic compound of zinc is the acetate (Zinc acetate, ). Organozinc compounds are those that contain zinc–carbon covalent bonds. Diethylzinc (Diethylzinc, ) is a reagent in synthetic chemistry. It was first reported in 1848 from the reaction of zinc and ethyl iodide, and was the first compound known to contain a metal–carbon sigma bond.


Test for zinc

Cobalticyanide paper (Rinnmann's test for Zn) can be used as a chemical indicator for zinc. 4 g of K3Co(CN)6 and 1 g of KClO3 is dissolved on 100 ml of water. Paper is dipped in the solution and dried at 100 °C. One drop of the sample is dropped onto the dry paper and heated. A green disc indicates the presence of zinc.


History


Ancient use

The Charaka Samhita, thought to have been written between 300 and 500 AD, mentions a metal which, when oxidized, produces ''pushpanjan'', thought to be zinc oxide. Zinc mines at Zawar, near Udaipur in India, have been active since the Mauryan period ( and 187 BCE). The smelting of metallic zinc here, however, appears to have begun around the 12th century AD.p. 46, Ancient mining and metallurgy in Rajasthan, S. M. Gandhi, chapter 2 in ''Crustal Evolution and Metallogeny in the Northwestern Indian Shield: A Festschrift for Asoke Mookherjee'', M. Deb, ed., Alpha Science Int'l Ltd., 2000, . One estimate is that this location produced an estimated million tonnes of metallic zinc and zinc oxide from the 12th to 16th centuries. Another estimate gives a total production of 60,000 tonnes of metallic zinc over this period. The Rasaratna Samuccaya, written in approximately the 13th century AD, mentions two types of zinc-containing ores: one used for metal extraction and another used for medicinal purposes. Various isolated examples of the use of impure zinc in ancient times have been discovered. Zinc ores were used to make the zinc–copper alloy
brass Brass is an alloy of copper Copper is a chemical element with the Symbol (chemistry), symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductility, ductile metal with very high thermal conductivity, thermal a ...
thousands of years prior to the discovery of zinc as a separate element. Judean brass from the 14th to 10th centuries BC contains 23% zinc. Knowledge of how to produce brass spread to Ancient Greece by the 7th century BC, but few varieties were made. Ornaments made of
alloy An alloy is an admixture of metal A metal (from Ancient Greek, Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts Elec ...
s containing 80–90% zinc, with lead, iron,
antimony Antimony is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same ...
, and other metals making up the remainder, have been found that are 2,500 years old. A possibly prehistoric statuette containing 87.5% zinc was found in a Dacian archaeological site. The oldest known pills were made of the zinc carbonates hydrozincite and smithsonite. The pills were used for sore eyes and were found aboard the Roman ship Relitto del Pozzino, wrecked in 140 BC. The manufacture of brass was known to the Ancient Rome, Romans by about 30 BC. They made brass by heating powdered Calamine (mineral), calamine (zinc
silicate In chemistry Chemistry is the scientific discipline involved with Chemical element, elements and chemical compound, compounds composed of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they unde ...
or carbonate), charcoal and copper together in a crucible. The resulting calamine brass was then either cast or hammered into shape for use in weaponry. Some coins struck by Romans in the Christian era are made of what is probably calamine brass. Strabo writing in the 1st century BC (but quoting a now lost work of the 4th century BC historian Theopompus) mentions "drops of false silver" which when mixed with copper make brass. This may refer to small quantities of zinc that is a by-product of smelting sulfide ores. Zinc in such remnants in smelting ovens was usually discarded as it was thought to be worthless. The Berne zinc tablet is a votive plaque dating to Roman Gaul made of an alloy that is mostly zinc.


Early studies and naming

Zinc was distinctly recognized as a metal under the designation of ''Yasada'' or Jasada in the medical Lexicon ascribed to the Hindu king Madanapala (of Taka dynasty) and written about the year 1374. (public domain text) Smelting and extraction of impure zinc by reducing calamine with wool and other organic substances was accomplished in the 13th century in India. The Chinese did not learn of the technique until the 17th century. Alchemy, Alchemists burned zinc metal in air and collected the resulting zinc oxide on a Condenser (heat transfer), condenser. Some alchemists called this zinc oxide ''lana philosophica'', Latin for "philosopher's wool", because it collected in wooly tufts, whereas others thought it looked like white snow and named it ''nix album''. The name of the metal was probably first documented by
Paracelsus Paracelsus (; c. 1493 – 24 September 1541), born Theophrastus von Hohenheim (full name Philippus Aureolus Theophrastus Bombastus von Hohenheim), was a Swiss physician, alchemist Depiction of Ouroboros from the alchemical treatise ''Aurora c ...

Paracelsus
, a Swiss-born German alchemist, who referred to the metal as "zincum" or "zinken" in his book ''Liber Mineralium II'', in the 16th century. The word is probably derived from the German , and supposedly meant "tooth-like, pointed or jagged" (metallic zinc crystals have a needle-like appearance). ''Zink'' could also imply "tin-like" because of its relation to German ''zinn'' meaning tin. Yet another possibility is that the word is derived from the Persian language, Persian word ''seng'' meaning stone. The metal was also called Indian tin, tutanego, calamine, and spinter. German metallurgist Andreas Libavius received a quantity of what he called "calay" of Malabar from a cargo ship captured from the Portuguese in 1596. Libavius described the properties of the sample, which may have been zinc. Zinc was regularly imported to Europe from the Orient in the 17th and early 18th centuries, but was at times very expensive.An East India Company ship carrying a cargo of nearly pure zinc metal from the Orient sank off the coast Sweden in 1745.


Isolation

Metallic zinc was isolated in India by 1300 AD, much earlier than in the West. Before it was isolated in Europe, it was imported from India in about 1600 CE. Postlewayt, Postlewayt's ''Universal Dictionary'', a contemporary source giving technological information in Europe, did not mention zinc before 1751 but the element was studied before then. Flemish metallurgist and alchemist P. M. de Respour reported that he had extracted metallic zinc from zinc oxide in 1668. By the start of the 18th century, Étienne François Geoffroy described how zinc oxide condenses as yellow crystals on bars of iron placed above zinc ore that is being smelted. In Britain, John Lane (metallurgist), John Lane is said to have carried out experiments to smelt zinc, probably at Landore, prior to his bankruptcy in 1726. In 1738 in Great Britain, William Champion (metallurgist), William Champion patented a process to extract zinc from calamine in a vertical retort-style smelter. His technique resembled that used at Zawar zinc mines in
Rajasthan Rajasthan ( ; literally, "Land of Kings") is a States and union territories of India, state in northern India. The state covers an area of or 10.4 percent of the total geographical area of India. It is the List of states and union territories ...

Rajasthan
, but no evidence suggests he visited the Orient. Champion's process was used through 1851. German chemist Andreas Sigismund Marggraf, Andreas Marggraf normally gets credit for discovering pure metallic zinc, even though Swedish chemist Anton von Swab had distilled zinc from calamine four years previously. In his 1746 experiment, Marggraf heated a mixture of calamine and charcoal in a closed vessel without copper to obtain a metal. This procedure became commercially practical by 1752.


Later work

William Champion's brother, John, patented a process in 1758 for calcining zinc sulfide into an oxide usable in the retort process. Prior to this, only calamine could be used to produce zinc. In 1798, Johann Christian Ruberg improved on the smelting process by building the first horizontal retort smelter. Jean-Jacques Daniel Dony built a different kind of horizontal zinc smelter in Belgium that processed even more zinc. Italian doctor
Luigi Galvani Luigi Galvani (, also ; ; la, Aloysius Galvanus; 9 September 1737 – 4 December 1798) was an Italian physician, physicist, biologist and philosopher, who discovered animal electricity. He is recognized as the pioneer of bioelectromagnetics. In ...
discovered in 1780 that connecting the spinal cord of a freshly dissected frog to an iron rail attached by a brass hook caused the frog's leg to twitch. He incorrectly thought he had discovered an ability of nerves and muscles to create
electricity Electricity is the set of physical phenomena associated with the presence and motion Image:Leaving Yongsan Station.jpg, 300px, Motion involves a change in position In physics, motion is the phenomenon in which an object changes its positio ...

electricity
and called the effect "bioelectricity, animal electricity". The galvanic cell and the process of galvanization were both named for Luigi Galvani, and his discoveries paved the way for Battery (electricity), electrical batteries, galvanization, and cathodic protection. Galvani's friend,
Alessandro Volta Alessandro Giuseppe Antonio Anastasio Volta (, ; 18 February 1745 – 5 March 1827) was an Italian physicist, chemist, and pioneer of electricity Electricity is the set of physical phenomena associated with the presence and motion ...
, continued researching the effect and invented the Voltaic pile in 1800. Volta's pile consisted of a stack of simplified galvanic cells, each being one plate of copper and one of zinc connected by an electrolyte. By stacking these units in series, the Voltaic pile (or "battery") as a whole had a higher voltage, which could be used more easily than single cells. Electricity is produced because the Volta potential between the two metal plates makes electrons flow from the zinc to the copper and corrode the zinc. The non-magnetic character of zinc and its lack of color in solution delayed discovery of its importance to biochemistry and nutrition. This changed in 1940 when carbonic anhydrase, an enzyme that scrubs carbon dioxide from blood, was shown to have zinc in its active site. The digestive enzyme carboxypeptidase became the second known zinc-containing enzyme in 1955.


Production


Mining and processing

Zinc is the fourth most common metal in use, trailing only
iron Iron () is a chemical element with Symbol (chemistry), symbol Fe (from la, Wikt:ferrum, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 element, group 8 of the periodic table. It is, Abundance ...

iron
,
aluminium Aluminium (aluminum in American American(s) may refer to: * American, something of, from, or related to the United States of America, commonly known as the United States The United States of America (USA), commonly known as the Unit ...
, and
copper Copper is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same nu ...

copper
with an annual production of about 13 million tonnes. The world's largest zinc producer is Nyrstar, a merger of the Australian OZ Minerals and the Belgian Umicore. About 70% of the world's zinc originates from mining, while the remaining 30% comes from recycling secondary zinc. Commercially pure zinc is known as Special High Grade, often abbreviated ''SHG'', and is 99.995% pure. Worldwide, 95% of new zinc is mined from sulfide, sulfidic ore deposits, in which sphalerite (ZnS) is nearly always mixed with the sulfides of copper, lead and iron. Zinc mines are scattered throughout the world, with the main areas being China, Australia, and Peru. China produced 38% of the global zinc output in 2014. Zinc metal is produced using extractive metallurgy. The ore is finely ground, then put through
froth flotation of the froth surface. Froth flotation is a process for selectively separating hydrophobic In chemistry Chemistry is the scientific discipline involved with Chemical element, elements and chemical compound, compounds composed of atoms, m ...
to separate minerals from gangue (on the property of hydrophobicity), to get a zinc sulfide ore concentrate consisting of about 50% zinc, 32% sulfur, 13% iron, and 5% . Roasting (metallurgy), Roasting converts the zinc sulfide concentrate to zinc oxide: :2 ZnS + 3 → 2 ZnO + 2 The sulfur dioxide is used for the production of sulfuric acid, which is necessary for the leaching process. If deposits of
zinc carbonate Smithsonite, also known as turkey fat or zinc spar, is zinc carbonate ( Zn C O3), a mineral ore of zinc. Historically, smithsonite was identified with hemimorphite before it was realized that they were two different minerals. The two minerals are ve ...

zinc carbonate
, zinc silicate, or zinc-spinel (like the Skorpion Zinc, Skorpion Deposit in Namibia) are used for zinc production, the roasting can be omitted. For further processing two basic methods are used: pyrometallurgy or
electrowinning Electrowinning, also called electroextraction, is the electrodeposition of metal A metal (from Ancient Greek, Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, s ...
. Pyrometallurgy reduces zinc oxide with carbon or carbon monoxide at into the metal, which is distilled as zinc vapor to separate it from other metals, which are not volatile at those temperatures. The zinc vapor is collected in a condenser. The equations below describe this process: :2 ZnO + C → 2 Zn + : ZnO + CO → Zn + In
electrowinning Electrowinning, also called electroextraction, is the electrodeposition of metal A metal (from Ancient Greek, Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, s ...
, zinc is leached from the ore concentrate by
sulfuric acid Sulfuric acid (American spelling Despite the various English dialects spoken from country to country and within different regions of the same country, there are only slight regional variations in English orthography English orthograp ...

sulfuric acid
and impurities are precipitated: :ZnO + → + Finally, the zinc is reduced by electrolysis. :2 + 2 → 2 Zn + 2 + The sulfuric acid is regenerated and recycled to the leaching step. When galvanised feedstock is fed to an electric arc furnace, the zinc is recovered from the dust by a number of processes, predominantly the Waelz process (90% as of 2014).


Environmental impact

Refinement of sulfidic zinc ores produces large volumes of sulfur dioxide and
cadmium Cadmium is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same num ...
vapor. Smelter slag and other residues contain significant quantities of metals. About 1.1 million tonnes of metallic zinc and 130 thousand tonnes of lead were mined and smelted in the Belgian towns of Kelmis, La Calamine and Plombières between 1806 and 1882. The dumps of the past mining operations leach zinc and cadmium, and the sediments of the Geul River contain non-trivial amounts of metals. About two thousand years ago, emissions of zinc from mining and smelting totaled 10 thousand tonnes a year. After increasing 10-fold from 1850, zinc emissions peaked at 3.4 million tonnes per year in the 1980s and declined to 2.7 million tonnes in the 1990s, although a 2005 study of the Arctic troposphere found that the concentrations there did not reflect the decline. Man-made and natural emissions occur at a ratio of 20 to 1. Zinc in rivers flowing through industrial and mining areas can be as high as 20 ppm. Effective sewage treatment greatly reduces this; treatment along the Rhine, for example, has decreased zinc levels to 50 ppb. Concentrations of zinc as low as 2 ppm adversely affects the amount of oxygen that fish can carry in their blood. soil contamination, Soils contaminated with zinc from mining, refining, or fertilizing with zinc-bearing sludge can contain several grams of zinc per kilogram of dry soil. Levels of zinc in excess of 500 ppm in soil interfere with the ability of plants to absorb other Dietary mineral, essential metals, such as iron and manganese. Zinc levels of 2000 ppm to 180,000 ppm (18%) have been recorded in some soil samples.


Applications

Major applications of zinc include (numbers are given for the US) # Galvanization, Galvanizing (55%) #
Brass Brass is an alloy of copper Copper is a chemical element with the Symbol (chemistry), symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductility, ductile metal with very high thermal conductivity, thermal a ...
and bronze (16%) # Other alloys (21%) # Miscellaneous (8%)


Anti-corrosion and batteries

Zinc is most commonly used as an anti-corrosion agent, and galvanization (coating of
iron Iron () is a chemical element with Symbol (chemistry), symbol Fe (from la, Wikt:ferrum, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 element, group 8 of the periodic table. It is, Abundance ...

iron
or steel) is the most familiar form. In 2009 in the United States, 55% or 893,000 tons of the zinc metal was used for galvanization. Zinc is more reactive than iron or steel and thus will attract almost all local oxidation until it completely corrodes away. A protective surface layer of oxide and carbonate ( forms as the zinc corrodes. This protection lasts even after the zinc layer is scratched but degrades through time as the zinc corrodes away. The zinc is applied electrochemically or as molten zinc by
hot-dip galvanizing Hot-dip galvanization is a form of galvanization Galvanization or galvanizing ( also spelled galvanisation or galvanising) is the process of applying a protective zinc Zinc is a chemical element with the Symbol (chemistry), symbol Zn a ...
or spraying. Galvanization is used on chain-link fencing, guard rails, suspension bridges, lightposts, metal roofs, heat exchangers, and car bodies. The relative reactivity of zinc and its ability to attract oxidation to itself makes it an efficient sacrificial anode in cathodic protection (CP). For example, cathodic protection of a buried pipeline can be achieved by connecting anodes made from zinc to the pipe. Zinc acts as the anode (negative terminus) by slowly corroding away as it passes electric current to the steel pipeline.Electric current will naturally flow between zinc and steel but in some circumstances inert anodes are used with an external DC source. Zinc is also used to cathodically protect metals that are exposed to sea water. A zinc disc attached to a ship's iron rudder will slowly corrode while the rudder stays intact. Similarly, a zinc plug attached to a propeller or the metal protective guard for the keel of the ship provides temporary protection. With a standard electrode potential (SEP) of −0.76 volts, zinc is used as an anode material for batteries. (More reactive lithium (SEP −3.04 V) is used for anodes in Lithium battery, lithium batteries ). Powdered zinc is used in this way in alkaline battery, alkaline batteries and the case (which also serves as the anode) of Zinc–carbon battery, zinc–carbon batteries is formed from sheet zinc. Zinc is used as the anode or fuel of the zinc–air battery/fuel cell. The Zinc–cerium battery, zinc-cerium redox flow battery also relies on a zinc-based negative half-cell.


Alloys

A widely used zinc alloy is brass, in which copper is alloyed with anywhere from 3% to 45% zinc, depending upon the type of brass. Brass is generally more ductile and stronger than copper, and has superior corrosion resistance. These properties make it useful in communication equipment, hardware, musical instruments, and water valves. Other widely used zinc alloys include nickel silver, typewriter metal, soft and aluminium solder, and commercial bronze. Zinc is also used in contemporary pipe organs as a substitute for the traditional lead/tin alloy in pipes. Alloys of 85–88% zinc, 4–10% copper, and 2–8% aluminium find limited use in certain types of machine bearings. Zinc has been the primary metal in Lincoln cent, American one cent coins (pennies) since 1982. The zinc core is coated with a thin layer of copper to give the appearance of a copper coin. In 1994, of zinc were used to produce 13.6 billion pennies in the United States. Alloys of zinc with small amounts of copper, aluminium, and magnesium are useful in die casting as well as spin casting, especially in the automotive, electrical, and hardware industries. These alloys are marketed under the name Zamak. An example of this is zinc aluminium. The low melting point together with the low viscosity of the alloy makes possible the production of small and intricate shapes. The low working temperature leads to rapid cooling of the cast products and fast production for assembly. Another alloy, marketed under the brand name Prestal, contains 78% zinc and 22% aluminium, and is reported to be nearly as strong as steel but as malleable as plastic. This superplasticity of the alloy allows it to be molded using die casts made of ceramics and cement. Similar alloys with the addition of a small amount of lead can be cold-rolled into sheets. An alloy of 96% zinc and 4% aluminium is used to make stamping dies for low production run applications for which ferrous metal dies would be too expensive. For building facades, roofing, and other applications for sheet metal formed by deep drawing, roll forming, or bending (metalworking), bending, zinc alloys with titanium and copper are used. Unalloyed zinc is too brittle for these manufacturing processes. As a dense, inexpensive, easily worked material, zinc is used as a
lead Lead is a chemical element with the Symbol (chemistry), symbol Pb (from the Latin ) and atomic number 82. It is a heavy metals, heavy metal that is density, denser than most common materials. Lead is Mohs scale of mineral hardness#Intermediate h ...

lead
replacement. In the wake of Lead poisoning, lead concerns, zinc appears in weights for various applications ranging from fishing to tire balances and flywheels. Cadmium zinc telluride (CZT) is a semiconductor, semiconductive alloy that can be divided into an array of small sensing devices. These devices are similar to an integrated circuit and can detect the energy of incoming
gamma ray A gamma ray, or gamma radiation (symbol γ or \gamma), is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves and so imparts the hi ...
photons. When behind an absorbing mask, the CZT sensor array can determine the direction of the rays.


Other industrial uses

Roughly one quarter of all zinc output in the United States in 2009 was consumed in zinc compounds; a variety of which are used industrially. Zinc oxide is widely used as a white pigment in paints and as a catalyst in the manufacture of rubber to disperse heat. Zinc oxide is used to protect rubber polymers and plastics from ultraviolet radiation (UV). The semiconductor properties of zinc oxide make it useful in varistors and photocopying products. The zinc zinc-oxide cycle is a two step Thermochemistry, thermochemical process based on zinc and zinc oxide for hydrogen production. Zinc chloride is often added to lumber as a fire retardant and sometimes as a wood preservative. It is used in the manufacture of other chemicals. Zinc methyl () is used in a number of organic organic synthesis, syntheses. Zinc sulfide (ZnS) is used in luminescence, luminescent pigments such as on the hands of clocks, X-ray and television screens, and luminous paints. Crystals of ZnS are used in lasers that operate in the mid-infrared part of the spectrum. Zinc sulfate is a chemical in dyes and pigments. Zinc pyrithione is used in antifouling paints. Zinc powder is sometimes used as a propellant in model rockets. When a compressed mixture of 70% zinc and 30%
sulfur Sulfur (in nontechnical British English: sulphur) is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consis ...

sulfur
powder is ignited there is a violent chemical reaction. This produces zinc sulfide, together with large amounts of hot gas, heat, and light. Zinc sheet metal is used to make zinc bar (counter), bars. , the most abundant isotope of zinc, is very susceptible to neutron activation, being Nuclear transmutation, transmuted into the highly radioactive , which has a half-life of 244 days and produces intense gamma ray, gamma radiation. Because of this, zinc oxide used in nuclear reactors as an anti-corrosion agent is depleted of before use, this is called depleted zinc oxide. For the same reason, zinc has been proposed as a Salted bomb, salting material for nuclear weapons (
cobalt Cobalt is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same numbe ...
is another, better-known salting material). A jacket of Isotope separation, isotopically enriched would be irradiated by the intense high-energy neutron flux from an exploding thermonuclear weapon, forming a large amount of significantly increasing the radioactivity of the weapon's Nuclear fallout, fallout. Such a weapon is not known to have ever been built, tested, or used. is used as a isotopic tracer, tracer to study how alloys that contain zinc wear out, or the path and the role of zinc in organisms. Zinc dithiocarbamate complexes are used as agricultural fungicides; these include Zineb, Metiram, Propineb and Ziram. Zinc naphthenate is used as wood preservative. Zinc in the form of Zinc dithiophosphate, ZDDP, is used as an anti-wear additive for metal parts in engine oil.


Organic chemistry

Organozinc compound, Organozinc chemistry is the science of compounds that contain carbon-zinc bonds, describing the physical properties, synthesis, and chemical reactions. Many organozinc compounds are important. Among important applications are * The Frankland-Duppa Reaction in which an oxalate ester (ROCOCOOR) reacts with an alkyl halide R'X, zinc and hydrochloric acid to form the α-hydroxycarboxylic esters RR'COHCOOR * On the downside, organozincs are much less nucleophilic than Grignards, and they are expensive and difficult to handle. Commercially available diorganozinc compounds are
dimethylzinc Dimethylzinc, also known as Zinc methyl, DMZ, or DMZn is a colorless volatile liquid Zn(CH3)2, formed by the action of methyl iodide on zinc at elevated temperature or on zinc sodium alloy. :2Zn + 2CH3I → Zn(CH3)2 + ZnI2 The sodium assists the ...
,
diethylzinc Diethylzinc (C2H5)2Zn, or DEZ, is a highly pyrophoric and reactive organozinc compound consisting of a zinc Zinc is a chemical element with the Symbol (chemistry), symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room tempe ...
and diphenylzinc. In one study, the active organozinc compound is obtained from much cheaper organobromine compound, organobromine precursors. Zinc has found many uses as a catalyst in organic synthesis including asymmetric synthesis, being cheap and easily available alternative to precious metal complexes. The results (yield and enantiomeric excess) obtained with chiral zinc catalysts are comparable to those achieved with palladium, ruthenium, iridium and others, and zinc becomes a metal catalyst of choice.


Dietary supplement

is one compound used for the delivery of zinc as a dietary supplement., alt=Skeletal chemical formula of a planar compound featuring a Zn atom in the center, symmetrically bonded to four oxygens. Those oxygens are further connected to linear COH chains. In most single-tablet, over-the-counter, daily vitamin and Dietary mineral, mineral supplements, zinc is included in such forms as
zinc oxide Zinc oxide is an inorganic compound with the Chemical formula, formula . ZnO is a white powder that is insoluble in water. It is used as an additive in numerous materials and products including cosmetics, food supplements, rubbers, plastics, cerami ...

zinc oxide
, zinc acetate, or . Generally, zinc supplement is recommended where there is high risk of zinc deficiency (such as low and middle income countries) as a preventive measure. Although zinc sulfate is a commonly used zinc form, zinc citrate, gluconate and picolinate may be valid options as well. These forms are better absorbed than zinc oxide.


Gastroenteritis

Zinc is an inexpensive and effective part of treatment of
diarrhea Diarrhea, also spelled diarrhoea, is the condition of having at least three loose, liquid, or watery bowel movements each day. It often lasts for a few days and can result in dehydration In physiology, dehydration is a lack of total body ...
among children in the developing world. Zinc becomes depleted in the body during diarrhea and replenishing zinc with a 10- to 14-day course of treatment can reduce the duration and severity of diarrheal episodes and may also prevent future episodes for as long as three months. Gastroenteritis is strongly attenuated by ingestion of zinc, possibly by direct antimicrobial action of the ions in the gastrointestinal tract, or by the absorption of the zinc and re-release from immune cells (all granulocytes secrete zinc), or both.


Common cold


Weight gain

Zinc deficiency may lead to loss of appetite. The use of zinc in the treatment of anorexia has been advocated since 1979. At least 15 clinical trials have shown that zinc improved weight gain in anorexia. A 1994 trial showed that zinc doubled the rate of body mass increase in the treatment of anorexia nervosa. Deficiency of other nutrients such as tyrosine, tryptophan and thiamine could contribute to this phenomenon of "malnutrition-induced malnutrition". A meta-analysis of 33 prospective intervention trials regarding zinc supplementation and its effects on the growth of children in many countries showed that zinc supplementation alone had a statistically significant effect on linear growth and body weight gain, indicating that other deficiencies that may have been present were not responsible for growth retardation.


Other

A Cochrane review stated that people taking zinc supplement may be less likely to progress to age-related macular degeneration. Zinc supplement is an effective treatment for acrodermatitis enteropathica, a genetic disorder affecting zinc absorption that was previously fatal to affected infants. Zinc deficiency has been associated with major depressive disorder (MDD), and zinc supplements may be an effective treatment.


Topical use

Topical administration, Topical preparations of zinc include those used on the skin, often in the form of
zinc oxide Zinc oxide is an inorganic compound with the Chemical formula, formula . ZnO is a white powder that is insoluble in water. It is used as an additive in numerous materials and products including cosmetics, food supplements, rubbers, plastics, cerami ...

zinc oxide
. Zinc preparations can protect against sunburn in the summer and windburn in the winter. Applied thinly to a baby's diaper area (perineum) with each diaper change, it can protect against diaper rash. Chelated zinc is used in toothpastes and mouthwashes to prevent halitosis, bad breath; zinc citrate helps reduce the build-up of Calculus (dental), calculus (tartar). Zinc pyrithione is widely included in shampoos to prevent dandruff. Topical zinc has also been shown to effectively treat, as well as prolong remission in genital herpes.


Biological role

Zinc is an essential trace element for humans and other animals, for plants and for microorganisms. Zinc is required for the function of over 300 enzymes and 1000 transcription factors, and is stored and transferred in metallothioneins. It is the second most abundant trace metal in humans after iron and it is the only metal which appears in all Enzyme#Naming conventions, enzyme classes. In proteins, zinc ions are often coordinated to the amino acid side chains of aspartic acid, glutamic acid, cysteine and histidine. The theoretical and computational description of this zinc binding in proteins (as well as that of other transition metals) is difficult. Roughly  grams of zinc are distributed throughout the human body. Most zinc is in the brain, muscle, bones, kidney, and liver, with the highest concentrations in the prostate and parts of the eye. Semen is particularly rich in zinc, a key factor in prostate gland function and reproductive organ growth. Zinc homeostasis of the body is mainly controlled by the intestine. Here, SLC39A4, ZIP4 and especially TRPM7 were linked to intestinal zinc uptake essential for postnatal survival. In humans, the biological roles of zinc are ubiquitous. It interacts with "a wide range of organic ligands", and has roles in the metabolism of RNA and DNA, signal transduction, and gene expression. It also regulates apoptosis. A review from 2015 indicated that about 10% of human proteins (~3000) bind zinc, in addition to hundreds more that transport and traffic zinc; a similar ''in silico'' study in the plant ''Arabidopsis thaliana'' found 2367 zinc-related proteins. In the brain, zinc is stored in specific synaptic vesicles by glutamatergic neurons and can modulate neuronal excitability. It plays a key role in synaptic plasticity and so in learning. Zinc homeostasis also plays a critical role in the functional regulation of the central nervous system. Dysregulation of zinc homeostasis in the central nervous system that results in excessive synaptic zinc concentrations is believed to induce neurotoxicity through mitochondrial oxidative stress (e.g., by disrupting certain enzymes involved in the electron transport chain, including complex I, complex III, and α-ketoglutarate dehydrogenase), the dysregulation of calcium homeostasis, glutamatergic neuronal excitotoxicity, and interference with intraneuronal signal transduction. L- and D-histidine facilitate brain zinc uptake. SLC30A3 is the primary Solute carrier family#Solute carrier family 30, zinc transporter involved in cerebral zinc homeostasis.


Enzymes

File:Zinc finger rendered.png, Zinc fingers help read DNA sequences., alt=A twisted band, with one side painted blue and another gray. Its two ends are connected through some chemical species to a green atom (zinc). Zinc is an efficient Lewis acid, making it a useful catalytic agent in hydroxylation and other enzymatic reactions. The metal also has a flexible coordination geometry, which allows proteins using it to rapidly shift protein structure, conformations to perform biological reactions. Two examples of zinc-containing enzymes are carbonic anhydrase and carboxypeptidase, which are vital to the processes of
carbon dioxide Carbon dioxide (chemical formula ) is a colorless gas with a density about 53% higher than that of dry air. Carbon dioxide molecules consist of a carbon atom covalent bond, covalently double bonded to two oxygen atoms. It occurs naturally in At ...

carbon dioxide
() regulation and digestion of proteins, respectively. In vertebrate blood, carbonic anhydrase converts into bicarbonate and the same enzyme transforms the bicarbonate back into for exhalation through the lungs. Without this enzyme, this conversion would occur about one million times slower at the normal blood pH of 7 or would require a pH of 10 or more. The non-related β-carbonic anhydrase is required in plants for leaf formation, the synthesis of indole-3-acetic acid, indole acetic acid (auxin) and alcoholic fermentation. Carboxypeptidase cleaves peptide linkages during digestion of proteins. A coordinate covalent bond is formed between the terminal peptide and a C=O group attached to zinc, which gives the carbon a positive charge. This helps to create a hydrophobic pocket on the enzyme near the zinc, which attracts the non-polar part of the protein being digested.


Signalling

Zinc has been recognized as a messenger, able to activate signalling pathways. Many of these pathways provide the driving force in aberrant cancer growth. They can be targeted through Zinc transporter protein, ZIP transporters.


Other proteins

Zinc serves a purely structural role in zinc fingers, twists and clusters. Zinc fingers form parts of some transcription factors, which are proteins that recognize DNA sequence, DNA base sequences during the replication and transcription of DNA. Each of the nine or ten ions in a zinc finger helps maintain the finger's structure by coordinately binding to four amino acids in the transcription factor. The transcription factor wraps around the DNA helix and uses its fingers to accurately bind to the DNA sequence. In blood plasma, zinc is bound to and transported by albumin (60%, low-affinity) and transferrin (10%). Because transferrin also transports iron, excessive iron reduces zinc absorption, and vice versa. A similar antagonism exists with copper. The concentration of zinc in blood plasma stays relatively constant regardless of zinc intake. Cells in the salivary gland, prostate, immune system, and intestine use Cell signaling, zinc signaling to communicate with other cells. Zinc may be held in metallothionein reserves within microorganisms or in the intestines or liver of animals. Metallothionein in intestinal cells is capable of adjusting absorption of zinc by 15–40%. However, inadequate or excessive zinc intake can be harmful; excess zinc particularly impairs copper absorption because metallothionein absorbs both metals. The human dopamine transporter contains a affinity (pharmacology), high affinity extracellular zinc binding site which, upon zinc binding, inhibits dopamine reuptake and amplifies amphetamine-induced neurotransmitter efflux, dopamine efflux ''in vitro''. The human serotonin transporter and norepinephrine transporter do not contain zinc binding sites. Some EF hand, EF-hand Calcium-binding protein, calcium binding proteins such as S100 protein, S100 or Neuronal calcium sensor-1, NCS-1 are also able to bind zinc ions.


Nutrition


Dietary recommendations

The U.S. Institute of Medicine (IOM) updated Estimated Average Requirements (EARs) and Recommended Dietary Allowances (RDAs) for zinc in 2001. The current EARs for zinc for women and men ages 14 and up is 6.8 and 9.4 mg/day, respectively. The RDAs are 8 and 11 mg/day. RDAs are higher than EARs so as to identify amounts that will cover people with higher than average requirements. RDA for pregnancy is 11 mg/day. RDA for lactation is 12 mg/day. For infants up to 12 months the RDA is 3 mg/day. For children ages 1–13 years the RDA increases with age from 3 to 8 mg/day. As for safety, the IOM sets Tolerable upper intake levels (ULs) for vitamins and minerals when evidence is sufficient. In the case of zinc the adult UL is 40 mg/day (lower for children). Collectively the EARs, RDAs, AIs and ULs are referred to as Dietary Reference Intakes (DRIs). The European Food Safety Authority (EFSA) refers to the collective set of information as Dietary Reference Values, with Population Reference Intake (PRI) instead of RDA, and Average Requirement instead of EAR. AI and UL are defined the same as in the United States. For people ages 18 and older the PRI calculations are complex, as the EFSA has set higher and higher values as the phytate content of the diet increases. For women, PRIs increase from 7.5 to 12.7 mg/day as phytate intake increases from 300 to 1200 mg/day; for men the range is 9.4 to 16.3 mg/day. These PRIs are higher than the U.S. RDAs. The EFSA reviewed the same safety question and set its UL at 25 mg/day, which is much lower than the U.S. value. For U.S. food and dietary supplement labeling purposes the amount in a serving is expressed as a percent of Daily Value (%DV). For zinc labeling purposes 100% of the Daily Value was 15 mg, but on May 27, 2016, it was revised to 11 mg. A table of the old and new adult daily values is provided at Reference Daily Intake.


Dietary intake

Animal products such as meat, fish, shellfish, fowl, eggs, and dairy contain zinc. The concentration of zinc in plants varies with the level in the soil. With adequate zinc in the soil, the food plants that contain the most zinc are wheat (germ and bran) and various seeds, including sesame, poppy, alfalfa, celery, and Mustard (condiment), mustard. Zinc is also found in beans, nut (fruit), nuts, almonds, whole grains, pumpkin seeds, sunflower seeds, and blackcurrant. Other sources include food fortification, fortified food and dietary supplements in various forms. A 1998 review concluded that zinc oxide, one of the most common supplements in the United States, and zinc carbonate are nearly insoluble and poorly absorbed in the body. This review cited studies that found lower plasma zinc concentrations in the subjects who consumed zinc oxide and zinc carbonate than in those who took zinc acetate and sulfate salts. For fortification, however, a 2003 review recommended cereals (containing zinc oxide) as a cheap, stable source that is as easily absorbed as the more expensive forms. A 2005 study found that various compounds of zinc, including oxide and sulfate, did not show statistically significant differences in absorption when added as fortificants to maize tortillas.


Deficiency

Nearly two billion people in the developing world are deficient in zinc. Groups at risk include children in developing countries and elderly with chronic illnesses. In children, it causes an increase in infection and diarrhea and contributes to the death of about 800,000 children worldwide per year. The World Health Organization advocates zinc supplementation for severe malnutrition and diarrhea. Zinc supplements help prevent disease and reduce mortality, especially among children with low birth weight or stunted growth. However, zinc supplements should not be administered alone, because many in the developing world have several deficiencies, and zinc interacts with other micronutrients. While zinc deficiency is usually due to insufficient dietary intake, it can be associated with malabsorption, acrodermatitis enteropathica, chronic liver disease, chronic renal disease, sickle cell disease, diabetes, malignancy, and other chronic illnesses. In the United States, a federal survey of food consumption determined that for women and men over the age of 19, average consumption was 9.7 and 14.2 mg/day, respectively. For women, 17% consumed less than the EAR, for men 11%. The percentages below EAR increased with age. The most recent published update of the survey (NHANES 2013–2014) reported lower averages – 9.3 and 13.2 mg/day – again with intake decreasing with age. Symptoms of mild zinc deficiency are diverse. Clinical outcomes include depressed growth, diarrhea, impotence and delayed sexual maturation, alopecia, eye and skin lesions, impaired appetite, altered cognition, impaired immune functions, defects in carbohydrate utilization, and reproductive teratogenesis. Zinc deficiency depresses immunity, but excessive zinc does also. Despite some concerns, western vegetarians and vegans do not suffer any more from overt zinc deficiency than meat-eaters. Major plant sources of zinc include cooked dried beans, sea vegetables, fortified cereals, soy foods, nuts, peas, and seeds. However, phytates in many whole-grains and fibers may interfere with zinc absorption and marginal zinc intake has poorly understood effects. The zinc chelation, chelator phytic acid, phytate, found in seeds and cereal bran, can contribute to zinc malabsorption. Some evidence suggests that more than the US RDA (8 mg/day for adult women; 11 mg/day for adult men) may be needed in those whose diet is high in phytates, such as some vegetarians. The European Food Safety Authority (EFSA) guidelines attempt to compensate for this by recommending higher zinc intake when dietary phytate intake is greater. These considerations must be balanced against the paucity of adequate zinc biomarkers, and the most widely used indicator, plasma zinc, has poor sensitivity and specificity.


Soil remediation

Species of ''Calluna'', ''Erica (plant), Erica'' and ''Vaccinium'' can grow in zinc-metalliferous soils, because translocation of toxic ions is prevented by the action of Ericoid mycorrhiza, ericoid mycorrhizal fungi.


Agriculture

Zinc deficiency appears to be the most common micronutrient deficiency in crop plants; it is particularly common in high-pH soils. Zinc-deficient soil is Tillage, cultivated in the cropland of about half of Turkey and India, a third of China, and most of Western Australia. Substantial responses to zinc fertilization have been reported in these areas. Plants that grow in soils that are zinc-deficient are more susceptible to disease. Zinc is added to the soil primarily through the weathering of rocks, but humans have added zinc through fossil fuel combustion, mine waste, phosphate fertilizers, pesticide (zinc phosphide), limestone, manure, sewage sludge, and particles from galvanized surfaces. Excess zinc is toxic to plants, although zinc toxicity is far less widespread.


Precautions


Toxicity

Although zinc is an essential requirement for good health, excess zinc can be harmful. Excessive absorption of zinc suppresses copper and iron absorption. The free zinc ion in solution is highly toxic to plants, invertebrates, and even vertebrate fish. The Free Ion Activity Model is well-established in the literature, and shows that just mole (unit), micromolar amounts of the free ion kills some organisms. A recent example showed 6 micromolar killing 93% of all ''Daphnia'' in water. The free zinc ion is a powerful Lewis acid up to the point of being corrosive. Stomach acid contains hydrochloric acid, in which metallic zinc dissolves readily to give corrosive zinc chloride. Swallowing a post-1982 American one Cent (United States coin), cent piece (97.5% zinc) can cause damage to the stomach lining through the high solubility of the zinc ion in the acidic stomach. Evidence shows that people taking 100–300 mg of zinc daily may suffer induced copper deficiency. A 2007 trial observed that elderly men taking 80 mg daily were hospitalized for urinary complications more often than those taking a placebo. Levels of 100–300 mg may interfere with the utilization of copper and iron or adversely affect cholesterol. Zinc in excess of 500 ppm in soil interferes with the plant absorption of other essential metals, such as iron and manganese. A condition called the zinc shakes or "zinc chills" can be induced by inhalation of zinc fumes while brazing or welding galvanized materials. Zinc is a common ingredient of denture cream which may contain between 17 and 38 mg of zinc per gram. Disability and even deaths from excessive use of these products have been claimed. The U.S. Food and Drug Administration (FDA) states that zinc damages nerve receptors in the nose, causing anosmia. Reports of anosmia were also observed in the 1930s when zinc preparations were used in a failed attempt to prevent polio infections. On June 16, 2009, the FDA ordered removal of zinc-based intranasal cold products from store shelves. The FDA said the loss of smell can be life-threatening because people with impaired smell cannot detect leaking gas or smoke, and cannot tell if food has spoiled before they eat it. Recent research suggests that the topical antimicrobial zinc pyrithione is a potent heat shock response inducer that may impair genomic integrity with induction of Poly ADP ribose polymerase, PARP-dependent energy crisis in cultured human keratinocytes and melanocytes.


Poisoning

In 1982, the United States Mint, US Mint began minting Cent (United States coin), pennies coated in copper but containing primarily zinc. Zinc pennies pose a risk of zinc toxicosis, which can be fatal. One reported case of chronic ingestion of 425 pennies (over 1 kg of zinc) resulted in death due to gastrointestinal bacterial and fungal sepsis. Another patient who ingested 12 grams of zinc showed only
lethargy Lethargy is a state of tiredness, weariness, fatigue, or lack of energy. It can be accompanied by depression, decreased motivation, or apathy. Lethargy can be a normal response to inadequate sleep, overexertion, overworking, stress, lack of exerc ...
and
ataxia Ataxia is a neurological sign consisting of lack of voluntary coordination of muscle movements that can include gait abnormality, speech changes, and abnormalities in eye movements. Ataxia is a clinical manifestation indicating dysfunction of ...
(gross lack of coordination of muscle movements). Several other cases have been reported of humans suffering zinc intoxication by the ingestion of zinc coins. Pennies and other small coins are sometimes ingested by dogs, requiring veterinary removal of the foreign objects. The zinc content of some coins can cause zinc toxicity, commonly fatal in dogs through severe hemolytic anemia and liver or kidney damage; vomiting and diarrhea are possible symptoms. Zinc is highly toxic in parrots and poisoning can often be fatal. The consumption of fruit juices stored in galvanized cans has resulted in mass parrot poisonings with zinc.


See also

* List of countries by zinc production * Spelter * Wet storage stain * Zinc alloy electroplating * Metal fume fever * Piotr Steinkeller


Notes


Citations


Bibliography

* * * * * * * * *


External links


Zinc Fact Sheet
from the U.S. National Institutes of Health
History & Etymology of Zinc



Reducing Agents > Zinc

American Zinc Association
Information about the uses and properties of zinc.
ISZB
International Society for Zinc Biology, founded in 2008. An international, nonprofit organization bringing together scientists working on the biological actions of zinc.
Zinc-UK
Founded in 2010 to bring together scientists in the United Kingdom working on zinc.

at ''The Periodic Table of Videos'' (University of Nottingham)
ZincBind
– a database of biological zinc binding sites. {{featured article Zinc, Alchemical substances Biology and pharmacology of chemical elements Chemical elements Dietary minerals Transition metals Pyrotechnic fuels Reducing agents Chemical elements with hexagonal close-packed structure Native element minerals