HOME

TheInfoList




The chloride
ion An ion () is an atom An atom is the smallest unit of ordinary matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyday objects that can be touched are ...
is the
anion An ion () is an atom An atom is the smallest unit of ordinary matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyday objects that can be touched are u ...
(negatively charged ion) Cl. It is formed when the
element Element may refer to: Science * 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 ...
chlorine Chlorine 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 s ...

chlorine
(a
halogen The halogens () are a group A group is a number A number is a mathematical object used to counting, count, measurement, measure, and nominal number, label. The original examples are the natural numbers 1, 2, 3, 4, and so forth. Numbers can b ...

halogen
) gains an
electron The electron is a subatomic particle In physical sciences, subatomic particles are smaller than atom An atom is the smallest unit of ordinary matter In classical physics and general chemistry, matter is any substance that has ma ...

electron
or when a
compound Compound may refer to: Architecture and built environments * Compound (enclosure), a cluster of buildings having a shared purpose, usually inside a fence or wall ** Compound (fortification), a version of the above fortified with defensive structu ...
such as
hydrogen chloride The compound Compound may refer to: Architecture and built environments * Compound (enclosure), a cluster of buildings having a shared purpose, usually inside a fence or wall ** Compound (fortification), a version of the above fortified with d ...

hydrogen chloride
is dissolved in water or other polar solvents. Chloride salts such as
sodium chloride Sodium chloride , commonly known as salt (although sea salt also contains other chemical salt (chemistry), salts), is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. With Molar mass, molar ...
are often very soluble in water.Green, John, and Sadru Damji. "Chapter 3." ''Chemistry''. Camberwell, Vic.: IBID, 2001. Print. It is an essential
electrolyte An electrolyte is a medium containing ions that is electrically conducting Electrical resistivity (also called specific electrical resistance or volume resistivity) is a fundamental property of a material that quantifies how strongly it resist ...

electrolyte
located in all body liquids responsible for maintaining acid/base balance, transmitting
nerve impulses In physiology Physiology (; ) is the scientific study of functions and mechanisms in a living system. As a sub-discipline of biology Biology is the natural science that studies life and living organisms, including their anatomy, phy ...
and regulating liquid flow in and out of cells. Less frequently, the word ''chloride'' may also form part of the "common" name of
chemical compound A chemical compound is a chemical substance A chemical substance is a form of matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyday objects that can be ...
s in which one or more chlorine
atom An atom is the smallest unit of ordinary matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyday objects that can be touched are ultimately composed of atom ...

atom
s are
covalently bonded A covalent bond is a chemical bond A chemical bond is a lasting attraction between atoms, ions or molecules that enables the formation of chemical compounds. The bond may result from the Coulomb's law, electrostatic force of attraction bet ...
. For example, methyl chloride, with the standard name
chloromethane Chloromethane, also called methyl chloride, Refrigerant-40, R-40 or HCC 40, is an organic compound , CH4; is among the simplest organic compounds. In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen c ...

chloromethane
(see IUPAC books) is an organic compound with a covalent C−Cl bond in which the chlorine is not an anion.


Electronic properties

A chloride ion (diameter 167  pm) is much larger than a chlorine atom (diameter 99 pm), respectively. The ion is colorless and diamagnetic. In aqueous solution, it is highly soluble in most cases; however, for some chloride salts, such as
silver chloride Silver chloride is a chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entity, molecular entities) composed of atoms from more than one chemical element, element held together by c ...

silver chloride
,
lead(II) chloride Lead(II) chloride (PbCl2) is an inorganic compound which is a white solid under ambient conditions. It is poorly soluble in water. Lead(II) chloride is one of the most important lead Lead is a chemical element with the Symbol (chemistry), symb ...

lead(II) chloride
, and
mercury(I) chloride Mercury(I) chloride is the chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entity, molecular entities) composed of atoms from more than one chemical element, element held together ...
, they are only slightly soluble in water. In aqueous solution, chloride is bound by the protic end of the water molecules.


Reactions of chloride

Chloride can be oxidized but not reduced. The first oxidation, as employed in the chlor-alkali process, is conversion to chlorine gas. Chlorine can be further oxidized to other oxides and oxyanions including
hypochlorite In chemistry Chemistry is the study of the properties and behavior of . It is a that covers the that make up matter to the composed of s, s and s: their composition, structure, properties, behavior and the changes they undergo during ...
(ClO, the active ingredient in chlorine
bleach Bleach is the generic name for any chemical product that is used industrially and domestically to remove color from a fabric or fiber or to clean or to remove stains in a process called bleaching. It often refers, specifically, to a dilute so ...

bleach
),
chlorine dioxide Chlorine dioxide is a chemical compound with the formula ClO2 that exists as yellowish-green gas above 11 °C, a reddish-brown liquid between 11 °C and −59 °C, and as bright orange crystals below −59 °C. It is an oxidizi ...

chlorine dioxide
(ClO2),
chlorate The chlorate anion has the formula . In this case, the chlorine Chlorine is a chemical element with the Symbol (chemistry), symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in t ...
(), and
perchlorate A perchlorate is a chemical compound containing the perchlorate ion, . The majority of perchlorates are commercially produced salts. They are mainly used as oxidizers for pyrotechnic devices and to control static electricity in food packaging. Pe ...
(). In terms of its acid–base properties, chloride is a
very weak base Very is an intensifier ''Intensifier'' ( abbreviated ) is a linguistic Linguistics is the science, scientific study of language. It encompasses the analysis of every aspect of language, as well as the methods for studying and modeling them. ...
as indicated by the negative value of the p''K''a of hydrochloric acid. Chloride can be protonated by
strong acid Acid strength is the tendency of an acid, symbolised by the chemical formula HA, to dissociate into a hydron (chemistry), proton, H+, and an anion, A-. The Dissociation (chemistry), dissociation of a strong acid in solution is effectively comple ...

strong acid
s, such as sulfuric acid: :NaCl + H2SO4 → NaHSO4 + HCl Ionic chloride salts reaction with other salts to exchange anions. The presence of chloride is often detected by its formation of an insoluble
silver chloride Silver chloride is a chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entity, molecular entities) composed of atoms from more than one chemical element, element held together by c ...

silver chloride
upon treatment with silver(I) ions: : Cl + Ag+ → AgCl The concentration of chloride in an assay can be determined using a
chloridometerA chloridometer is a measuring instrument A measuring instrument is a device to measure a physical quantity A physical quantity is any phenomenon that can be measured with an instrument or be calculated for. A physical quantity can be expressed a ...
, which detects silver ions once all chloride in the assay has precipitated via this reaction. Chlorided silver electrodes are commonly used in
electrophysiology Electrophysiology (from Greek , ''ēlektron'', "amber" etymology of "electron"">Electron#Etymology">etymology of "electron" , ''physis'', "nature, origin"; and , '' -logia'') is the branch of physiology Physiology (; ) is the scientific study ...
.


Other oxyanions

Chlorine can assume
oxidation state The oxidation state, or oxidation number, is the hypothetical charge Charge or charged may refer to: Arts, entertainment, and media Films * ''Charge, Zero Emissions/Maximum Speed'', a 2011 documentary Music * Charge (David Ford album), ''Charge' ...
s of −1, +1, +3, +5, or +7. Several neutral
chlorine oxide Chlorine Chlorine 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 ...
s are also known. :


Occurrence in nature

In nature, chloride is found primarily in seawater, which contains 1.94% chloride. Smaller quantities, though at higher concentrations, occur in certain inland seas and in subterranean brine wells, such as the
Great Salt Lake The Great Salt Lake, located in the northern part of the U.S. state of Utah, is the largest salt water lake in the Western Hemisphere, and the eighth-largest terminal lake in the world. In an average year the lake covers an area of approximat ...

Great Salt Lake
in
Utah Utah ( , ) is a state State may refer to: Arts, entertainment, and media Literature * ''State Magazine'', a monthly magazine published by the U.S. Department of State * The State (newspaper), ''The State'' (newspaper), a daily newspaper ...

Utah
and the
Dead Sea The Dead Sea ( he, יָם הַמֶּלַח lit. Sea of Salt; ar, البحر الميت , lit. ''the Dead Sea'',The first article ''al-'' is unnecessary and usually not used. or Buhayrat, Bahret or Birket Lut, ''lit.'' "Lake/Sea of Lot") is a s ...

Dead Sea
in
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
. Most chloride salts are soluble in water, thus, chloride-containing minerals are usually only found in abundance in dry climates or deep underground. Some chloride-containing minerals include
halite Halite (), commonly known as rock salt, is a type of 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 crysta ...

halite
(sodium chloride
NaCl Sodium chloride , commonly known as salt (although sea salt Sea salt is salt that is produced by the evaporation of seawater. It is used as a seasoning in foods, cooking Cooking or cookery is the art, science, and craft of using heat t ...

NaCl
),
sylvite Sylvite, or sylvine, is potassium chloride Potassium chloride (KCl, or potassium salt) is a metal halide Metal halides are compounds between metals and halogens. Some, such as sodium chloride are ionic, while others are covalently bonded. Cova ...

sylvite
(potassium chloride
KCl
KCl
),
bischofite Bischofite (bischofit) is a hydrous magnesium chloride mineral with formula MgCl2·6H2O. It belongs to halides and is a sea salt concentrate. It contains many macro- and micro-elements vital for human health, in much higher concentrations than can ...
(MgCl2∙6H2O),
carnallite Carnallite (also carnalite) is an mineral, a hydrated with formula KMgCl3·6(H2O). It is variably colored yellow to white, reddish, and sometimes colorless or blue. It is usually massive to fibrous with rare pseudohexagonal crystals. The miner ...
(KCl∙MgCl2∙6H2O), and
kainite Kainite ( or ) (KMg(SO4)Cl·3H2O) is an evaporite evaporated from the Dead Sea, Israel Evaporite () is the term for a water-soluble mineral sediment Sediment is a naturally occurring material that is broken down by processes of weathering ...

kainite
(KCl∙MgSO4∙3H2O). It is also found in evaporite minerals such as
chlorapatite Apatite is a group of phosphate minerals, usually referring to hydroxyapatite, fluorapatite and chlorapatite, with high concentrations of Hydroxide, OH−, Fluoride, F− and Chloride, Cl− ions, respectively, in the crystal. The formula of the ...
and
sodalite Sodalite ( ) is a royal blue Royal blue is both a bright shade and a dark shade of azure blue Blue is one of the three primary color, primary colours of pigments in painting and traditional colour theory, as well as in the RGB color ...

sodalite
.


Role in biology

Chloride has a major physiological significance, which includes regulation of
osmotic pressure
osmotic pressure
, electrolyte balance and acid-base homeostasis. Chloride is present in all
body fluid Body fluids, bodily fluids, or biofluids are liquid A liquid is a nearly incompressible In fluid mechanics or more generally continuum mechanics, incompressible flow (isochoric process, isochoric flow) refers to a fluid flow, flow in whic ...
s, and is the most abundant extracellular
anion An ion () is an atom An atom is the smallest unit of ordinary matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyday objects that can be touched are u ...
which accounts for around one third of
extracellular fluid In cell biology Cell biology (also cellular biology or cytology) is a branch of biology Biology is the natural science that studies life and living organisms, including their anatomy, physical structure, Biochemistry, chemical processes, ...
's
tonicity Tonicity is a measure of the effective osmotic pressure gradient; the water potential of two solution Image:SaltInWaterSolutionLiquid.jpg, Making a saline water solution by dissolving Salt, table salt (sodium chloride, NaCl) in water. The ...

tonicity
. Chloride is an essential
electrolyte An electrolyte is a medium containing ions that is electrically conducting Electrical resistivity (also called specific electrical resistance or volume resistivity) is a fundamental property of a material that quantifies how strongly it resist ...
, playing a key role in maintaining cell
homeostasis In , homeostasis is the state of steady internal, , and conditions maintained by . This is the condition of optimal functioning for the organism and includes many variables, such as and , being kept within certain pre-set limits (homeostatic r ...

homeostasis
and transmitting
action potentials In physiology Physiology (; ) is the scientific study of functions and mechanisms in a living system. As a sub-discipline of biology Biology is the natural science that studies life and living organisms, including their anatomy, phy ...
in neurons. It can flow through
chloride channels Chloride channels are a superfamily of poorly understood ion channel s (typically four per channel), 2 - outer vestibule, 3 - selectivity filter, 4 - diameter of selectivity filter, 5 - phosphorylation site, 6 - cell membrane. Ion channels are por ...
(including the GABAA receptor) and is transported by
KCC2 Potassium-chloride transporter member 5 (aka: KCC2 and SLC12A5) is a neuron-specific chloride potassium symporter responsible for establishing the chloride ion gradient in neurons through the maintenance of low intracellular chloride concentrations ...
and NKCC2 transporters. Chloride is usually (though not always) at a higher extracellular concentration, causing it to have a negative
reversal potential In a biological membrane A biological membrane, biomembrane or cell membrane is a selectively permeable membrane that separates cell from the external environment or creates intracellular compartments. Biological membranes, in the form of eu ...
(around −61 mV at 37 °C in a mammalian cell). Characteristic concentrations of chloride in model organisms are: in both ''E. coli'' and budding yeast are 10–200  mM (dependent on medium), in mammalian cells 5–100 mM and in
blood plasma Blood plasma is a yellowish liquid component of blood Blood is a body fluid in humans and other animals that delivers necessary substances such as nutrients and oxygen to the Cell (biology), cells and transports metabolic waste products ...
100 mM. The concentration of chloride in the blood is called serum chloride, and this concentration is regulated by the
kidneys The kidneys are two reddish-brown bean-shaped organs found in vertebrate Vertebrates () comprise all species of animal Animals (also called Metazoa) are multicellular eukaryotic organisms that form the Kingdom (biology), biological ...

kidneys
. A chloride ion is a structural component of some proteins; for example, it is present in the
amylase An amylase () is an enzyme that catalysis, catalyses the hydrolysis of starch (Latin ) into sugars. Amylase is present in the saliva of humans and some other mammals, where it begins the chemical process of digestion. Foods that contain large am ...
enzyme. For these roles, chloride is one of the essential
dietary mineral In the context of nutrition, a mineral 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 ...
(listed by its element name ''chlorine''). Serum chloride levels are mainly regulated by the kidneys through a variety of transporters that are present along the
nephron The nephron is the microscopic structural and functional unit of the kidney The kidneys are two reddish-brown bean-shaped organ (anatomy), organs found in vertebrates. They are located on the left and right in the retroperitoneal space, and in ...

nephron
. Most of the chloride, which is filtered by the
glomerulus ''Glomerulus'' () is a common term used in anatomy Anatomy (Greek ''anatomē'', 'dissection') is the branch of biology concerned with the study of the structure of organism In biology, an organism (from Ancient Greek, Greek: ὀργαν ...
, is reabsorbed by both proximal and distal tubules (majorly by proximal tubule) by both active and passive transport.


Corrosion

The presence of chlorides, such as in seawater, significantly worsens the conditions for
pitting corrosion Pitting corrosion, or pitting, is a form of extremely localized 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 tita ...
of most metals (including stainless steels, aluminum and high-alloyed materials). Chloride-induced corrosion of steel in concrete lead to a local breakdown of the protective oxide form in alkaline concrete, so that a subsequent localized corrosion attack takes place.


Environmental threats

Increased concentrations of chloride can cause a number of ecological effects in both aquatic and terrestrial environments. It may contribute to the acidification of streams, mobilize radioactive soil metals by ion exchange, affect the mortality and reproduction of aquatic plants and animals, promote the invasion of saltwater organisms into previously freshwater environments, and interfere with the natural mixing of lakes. Sodium chloride has also been shown to change the composition of microbial species at relatively low concentrations. It can also hinder the denitrification process, a microbial process essential to nitrate removal and the conservation of water quality, and inhibit the nitrification and respiration of organic matter.


Production

The
chlor-alkali The chloralkali process (also chlor-alkali and chlor Alkali#Alkali salts, alkali) is an industrial process for the electrolysis of NaCl, sodium chloride solutions. It is the technology used to Chlorine production, produce chlorine and sodium hydro ...
industry is a major consumer of the world's energy budget. This process converts sodium chloride into chlorine and sodium hydroxide, which are used to make many other materials and chemicals. The process involves two parallel reactions: :2 Cl → + 2 
e
e<sup>−</sup>
:2  + 2 e → H2 + 2 OH


Examples and uses

An example is table salt, which is
sodium chloride Sodium chloride , commonly known as salt (although sea salt also contains other chemical salt (chemistry), salts), is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. With Molar mass, molar ...
with the
chemical formula A chemical formula is a way of presenting information about the chemical proportions of s that constitute a particular or molecule, using symbols, numbers, and sometimes also other symbols, such as parentheses, dashes, brackets, commas and ...
NaCl. In
water Water (chemical formula H2O) is an , transparent, tasteless, odorless, and , which is the main constituent of 's and the s of all known living organisms (in which it acts as a ). It is vital for all known forms of , even though it provide ...
, it dissociates into Na+ and Cl ions. Salts such as
calcium chloride Calcium chloride is an inorganic compound, a salt with the chemical formula CaCl2. It is a white coloured crystalline solid at room temperature, and it is highly soluble in water. It can be created by neutralising hydrochloric acid with calc ...

calcium chloride
,
magnesium chloride Magnesium chloride is the name for the chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entity, molecular entities) composed of atoms from more than one chemical element, element h ...

magnesium chloride
,
potassium chloride Potassium chloride (KCl, or potassium salt) is a metal halide Metal halides are compounds between metals and halogens. Some, such as sodium chloride are ionic, while others are covalently bonded. Covalently bonded metal halides may be discrete m ...

potassium chloride
have varied uses ranging from medical treatments to cement formation. Calcium chloride (CaCl2) is a salt that is marketed in
pellet Pellets are small particles typically created by compressing an original material. Pellet or pellets may refer to: People * Alain Pellet (born 1947), French lawyer * Gustave Pellet (1859–1919), French publisher of art * Laurent Pellet (born 1970 ...
form for removing dampness from rooms. Calcium chloride is also used for maintaining unpaved roads and for fortifying roadbases for new construction. In addition, calcium chloride is widely used as a
de-icer De-icing is the process of removing snow, ice or frost from a surface. Anti-icing is understood to be the application of chemicals that not only de-ice but also remain on a surface and continue to delay the reformation of ice for a certain period ...
, since it is effective in lowering the
melting point The melting point (or, rarely, liquefaction point) of a substance is the temperature Temperature ( ) is a physical quantity that expresses hot and cold. It is the manifestation of thermal energy Thermal radiation in visible light can b ...

melting point
when applied to ice. Examples of covalently-bonded chlorides are
phosphorus trichloride Phosphorus 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 ...

phosphorus trichloride
,
phosphorus pentachloride Phosphorus pentachloride is the chemical compound with the formula PCl5. It is one of the most important phosphorus chlorides, others being PCl3 and POCl3. PCl5 finds use as a chlorinating reagent. It is a colourless, water-sensitive and mois ...

phosphorus pentachloride
, and
thionyl chloride Thionyl chloride is an inorganic compound with the chemical formula . It is a moderately volatile colourless liquid with an unpleasant acrid odour. Thionyl chloride is primarily used as a chlorinating reagent, with approximately per year being pro ...

thionyl chloride
, all three of which are reactive chlorinating
reagent A reagent is a substance or compound added to a system to cause a chemical reaction A chemical reaction is a process that leads to the chemical transformation of one set of chemical substance A chemical substance is a form of matter ...
s that have been used in a
laboratory A laboratory (; ; colloquially lab) is a facility that provides controlled conditions in which or technological research, s, and may be performed. Laboratory services are provided in a variety of settings: physicians' offices, clinics, hos ...

laboratory
.


Water quality and processing

A major application involving chloride is
desalination Desalination is a process that takes away mineral components from saline water Saline water (more commonly known as salt water) is water that contains a high concentration of solvation, dissolved salts (mainly sodium chloride). The salt conce ...
, which involves the energy intensive removal of chloride salts to give
potable water Drinking water, also known as potable water, is water Water is an Inorganic compound, inorganic, Transparency and translucency, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main ...

potable water
. In the
petroleum industry The petroleum industry, also known as the oil industry or the oil patch, includes the global processes of hydrocarbon exploration, exploration, extraction of petroleum, extraction, oil refinery, refining, Petroleum transport, transporting (often ...
, the chlorides are a closely monitored constituent of the mud system. An increase of the chlorides in the mud system may be an indication of drilling into a high-pressure saltwater formation. Its increase can also indicate the poor quality of a target sand. Chloride is also a useful and reliable chemical indicator of river and groundwater fecal contamination, as chloride is a non-reactive solute and ubiquitous to sewage and potable water. Many water regulating companies around the world utilize chloride to check the contamination levels of the rivers and potable water sources.


Food

Chloride salts such as
sodium chloride Sodium chloride , commonly known as salt (although sea salt also contains other chemical salt (chemistry), salts), is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. With Molar mass, molar ...
are used to preserve food and as nutrients or
condiment A condiment is a sauce In , a sauce is a , , or semi- food, served on or used in preparing other s. Most sauces are not normally consumed by themselves; they add flavor, moisture, and visual appeal to a dish. ''Sauce'' is a word taken fro ...
s.


See also

*
Halide A halide is a binary phase, of which one part is a halogen atom and the other part is an chemical element, element or radical (chemistry), radical that is less electronegative (or more electropositive) than the halogen, to make a, e.g., fluoride, ...
(compounds of halogens) *
Renal chloride reabsorption Renal reabsorption of chloride (Cl−) is a part of renal physiology Renal physiology (Latin Latin (, or , ) is a classical language A classical language is a language A language is a structured system of communication Commun ...


References

{{Chlorides Anions Leaving groups Dietary minerals