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Sulfur (in nontechnical British English: sulphur) is a
chemical element 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 du ...
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), m ...
 S and
atomic number 300px, The Rutherford–Bohr model of the hydrogen atom () or a hydrogen-like ion (). In this model it is an essential feature that the photon energy (or frequency) of the electromagnetic radiation emitted (shown) when an electron jumps from one ...
 16. It is abundant, multivalent and
nonmetal In , a nonmetal is a that usually gains s when reacting with a , and which forms an acid if combined with and . Nonmetals display more variety in color and state than do metals. About half are colored or colorless gases whereas nearly all m ...
lic. Under
normal conditions Normal conditions are a restriction on philosophical Philosophy (from , ) is the study of general and fundamental questions, such as those about reason, existence, knowledge Knowledge is a familiarity, awareness, or understanding ...
, sulfur atoms form cyclic octatomic molecules with a chemical formula S8. Elemental sulfur is a bright yellow,
crystal A crystal or crystalline solid is a solid Solid is one of the four fundamental states of matter (the others being liquid A liquid is a nearly incompressible fluid In physics, a fluid is a substance that continually Deformatio ...

crystal
line solid 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 ...
. Sulfur is the tenth most common element by mass in the universe and the fifth most common on Earth. Though sometimes found in pure,
native Native may refer to: People * Jus soli, citizenship by right of birth * Indigenous peoples, peoples with a set of specific rights based on their historical ties to a particular territory ** Native Americans (disambiguation) In arts and entertain ...
form, sulfur on Earth usually occurs as
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
and
sulfate minerals The sulfate minerals are a class of mineral 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), ...

sulfate minerals
. Being abundant in native form, sulfur was known in ancient times, being mentioned for its uses in
ancient India According to consensus in modern genetics, anatomically modern humans first arrived on the Indian subcontinent from Africa between 73,000 and 55,000 years ago. Quote: "Y-Chromosome and Mt-DNA data support the colonization of South Asia by mod ...

ancient India
,
ancient Greece Ancient Greece ( el, Ἑλλάς, Hellás) was a civilization belonging to a period of History of Greece, Greek history from the Greek Dark Ages of the 12th–9th centuries BC to the end of Classical Antiquity, antiquity ( AD 600). This era wa ...
,
China China (), officially the People's Republic of China (PRC; ), is a country in East Asia East Asia is the eastern region of Asia Asia () is Earth's largest and most populous continent, located primarily in the Eastern Hemisphere ...
, and
Egypt Egypt ( ar, مِصر, Miṣr), officially the Arab Republic of Egypt, is a transcontinental country This is a list of countries located on more than one continent A continent is one of several large landmasses. Generally identi ...

Egypt
. Historically and in literature sulfur is also called brimstone, which means "burning stone". Today, almost all elemental sulfur is produced as a byproduct of removing sulfur-containing contaminants from
natural gas Natural gas (also called fossil gas; sometimes just gas) is a naturally occurring hydrocarbon gas mixture consisting of methane and commonly including varying amounts of other higher alkanes, and sometimes a small percentage of carbon dioxid ...

natural gas
and
petroleum Petroleum, also known as crude oil and oil, is a naturally occurring, yellowish-black liquid A liquid is a nearly incompressible In fluid mechanics or more generally continuum mechanics, incompressible flow (isochoric process, isoc ...

petroleum
.. Downloa
here
The greatest commercial use of the element is the production of
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 orthogra ...

sulfuric acid
for sulfate and phosphate
fertilizer A fertilizer (American English American English (AmE, AE, AmEng, USEng, en-US), sometimes called United States English or U.S. English, is the set of varieties of the English language native to the United States. Currently, American E ...

fertilizer
s, and other chemical processes. Sulfur is used in
match A match is a tool for starting a fire BBQ. Fire is the rapid oxidation of a material in the exothermic chemical process of combustion, releasing heat, light, and various reaction Product (chemistry), products. Fire is hot because the con ...

match
es,
insecticide Insecticides are substances used to kill insects. They include ovicides and larvicides used against insect Egg (biology), eggs and larvae, respectively. Insecticides are used in agriculture, medicine, Industry (manufacturing), industry and by ...
s, and
fungicide Fungicides are biocidal 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 hav ...
s. Many sulfur compounds are odoriferous, and the smells of odorized natural gas, skunk scent, grapefruit, and garlic are due to
organosulfur Organosulfur compounds are organic compound , CH4; is among the simplest organic compounds. In chemistry Chemistry is the scientific discipline involved with Chemical element, elements and chemical compound, compounds composed of atoms, molec ...
compounds.
Hydrogen sulfide Hydrogen sulfide is a 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 havi ...

Hydrogen sulfide
gives the characteristic odor to rotting eggs and other biological processes. Sulfur is an
essential element 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 ...
for all life, but almost always in the form of
organosulfur compounds Organosulfur compounds are organic compound , CH4; is among the simplest organic compounds. In chemistry Chemistry is the scientific discipline involved with Chemical element, elements and chemical compound, compounds composed of atoms, molec ...
or metal sulfides. Three
amino acid Amino acids are organic compound In , organic compounds are generally any s that contain - . Due to carbon's ability to (form chains with other carbon s), millions of organic compounds are known. The study of the properties, reactions, a ...

amino acid
s (
cysteine Cysteine (symbol Cys or C; ) is a semiessential proteinogenic amino acid with the chemical formula, formula HOOC-CH-(NH2)-CH2-SH. The thiol side chain in cysteine often participates in enzymatic reactions as a nucleophile. The thiol is suscepti ...

cysteine
,
cystine Cystine is the oxidized dimer form of the amino acid Amino acids are organic compound , CH4; is among the simplest organic compounds. In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen chemica ...
, and
methionine Methionine (symbol Met or M) () is an essential amino acid An essential amino acid, or indispensable amino acid, is an amino acid that cannot be synthesized from scratch by the organism fast enough to supply its demand, and must therefore come ...

methionine
) and two vitamins (
biotin Biotin, also called vitamin B7, is one of the B vitamins B vitamins are a class of water-soluble vitamin A vitamin is an organic molecule , CH4; is among the simplest organic compounds. In chemistry, organic compounds are generally any ch ...

biotin
and
thiamine Thiamine, also known as thiamin or vitamin B1, is a vitamin A vitamin is an organic molecule , CH4; is among the simplest organic compounds. In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen ...

thiamine
) are organosulfur compounds. Many cofactors also contain sulfur, including
glutathione Glutathione (GSH) is an antioxidant Antioxidants are that inhibit , a that can produce and s that may damage the of organisms. Antioxidants such as s or (vitamin C) may act to inhibit these reactions. To balance , plants and animals ma ...

glutathione
,
thioredoxin Thioredoxin is a class of small redox protein Proteins are large biomolecules or macromolecules that are comprised of one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within orga ...
, and
iron–sulfur protein Iron–sulfur proteins (or iron–sulphur proteins in British English, British spelling) are proteins characterized by the presence of iron–sulfur clusters containing sulfide-linked di-, tri-, and tetrairon centers in variable oxidation states. I ...
s.
Disulfide 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 underg ...
s, S–S bonds, confer mechanical strength and insolubility of the protein
keratin Keratin () is one of a family of structural fibrous proteins also known as ''scleroproteins''. Alpha-keratin Alpha-keratin, or α-keratin, is a type of keratin Keratin () is one of a family of fibrous structural proteins known as Scleroprot ...

keratin
, found in outer skin, hair, and feathers. Sulfur is one of the core chemical elements needed for
biochemical Biochemistry or biological chemistry, is the study of chemical process In a scientific Science (from the Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. L ...
functioning and is an elemental
macronutrient A nutrient is a substance Substance may refer to: * Substance (Jainism), a term in Jain ontology to denote the base or owner of attributes * Chemical substance, a material with a definite chemical composition * Matter, anything that has mass and ta ...
for all living organisms.


Characteristics


Physical properties

Sulfur forms several polyatomic molecules. The best-known allotrope is
octasulfur Octasulfur is an inorganic 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, behavi ...
, cyclo-S8. The
point group 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 tha ...
of cyclo-S8 is D4d and its dipole moment is 0 D. Octasulfur is a soft, bright-yellow solid that is odorless, but impure samples have an odor similar to that of
match A match is a tool for starting a fire BBQ. Fire is the rapid oxidation of a material in the exothermic chemical process of combustion, releasing heat, light, and various reaction Product (chemistry), products. Fire is hot because the con ...

match
es. It melts at , boils at and sublimates easily. At , below its melting temperature, cyclo-octasulfur changes from α-octasulfur to the β- polymorph. The structure of the S8 ring is virtually unchanged by this phase change, which affects the intermolecular interactions. Between its melting and boiling temperatures, octasulfur changes its allotrope again, turning from β-octasulfur to γ-sulfur, again accompanied by a lower density but increased
viscosity The viscosity of a is a measure of its to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, has a higher viscosity than . Viscosity can be conceptualized as quantifying the inter ...

viscosity
due to the formation of
polymer A polymer (; Greek ''poly- Poly, from the Greek :wikt:πολύς, πολύς meaning "many" or "much", may refer to: Businesses * China Poly Group Corporation, a Chinese business group, and its subsidiaries: ** Poly Property, a Hong Kong inc ...

polymer
s. At higher temperatures, the viscosity decreases as depolymerization occurs. Molten sulfur assumes a dark red color above . The density of sulfur is about 2 g/cm3, depending on the allotrope; all of the stable allotropes are excellent electrical insulators.


Chemical properties

Sulfur burns with a blue flame with formation of
sulfur dioxide Sulfur dioxide (IUPAC The International Union of Pure and Applied Chemistry (IUPAC ) is an international federation of National Adhering OrganizationsNational Adhering Organizations in chemistry are the organizations that work as the autho ...
, which has a suffocating and irritating odor. Sulfur is insoluble in water but soluble in
carbon disulfide Carbon disulfide, also spelled as carbon disulphide, is a colorless volatility (chemistry), volatile liquid with the chemical formula, formula CS2. The Chemical compound, compound is used frequently as a building block in organic chemistry as well ...
and, to a lesser extent, in other nonpolar organic solvents, such as
benzene Benzene is an organic Organic may refer to: * Organic, of or relating to an organism, a living entity * Organic, of or relating to an anatomical organ (anatomy), organ Chemistry * Organic matter, matter that has come from a once-living organi ...

benzene
and
toluene Toluene (), also known as toluol (), is an aromatic hydrocarbon. It is a colorless, Water (molecule), water-insoluble liquid with the smell associated with paint thinners. It is a mono-substituted benzene derivative, consisting of a methyl group ( ...

toluene
. The first and second ionization energies of sulfur are 999.6 and 2252 kJ/mol, respectively. Despite such figures, the +2 oxidation state is rare, with +4 and +6 being more common. The fourth and sixth ionization energies are 4556 and 8495.8 kJ/mol, the magnitude of the figures caused by electron transfer between orbitals; these states are only stable with strong oxidants such as
fluorine Fluorine is a chemical element with the Chemical symbol, symbol F and atomic number 9. It is the lightest halogen and exists at Standard conditions for temperature and pressure, standard conditions as a highly toxic, pale yellow Diatomic molecule ...

fluorine
,
oxygen Oxygen is the 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 ...

oxygen
, and
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 the periodic table and its properties are mostly intermediate betw ...

chlorine
. Sulfur reacts with nearly all other elements with the exception of the noble gases, even with the notoriously unreactive metal
iridium Iridium is a with the Ir and 77. A very hard, brittle, silvery-white of the , iridium is considered to be the second-densest naturally occurring metal (after ) with a density of as defined by experimental . It is the most -resistant meta ...

iridium
(yielding iridium disulfide). Some of those reactions need elevated temperatures.


Isotopes

Sulfur has 23 known
isotope Isotopes are two or more types of atoms that have the same atomic number 300px, The Rutherford–Bohr model of the hydrogen atom () or a hydrogen-like ion (). In this model it is an essential feature that the photon energy (or frequency) of ...
s, four of which are stable: 32S (), 33S (), 34S (), and 36S (). Other than 35S, with a
half-life Half-life (symbol ''t''1⁄2) is the time required for a quantity to reduce to half of its initial value. The term is commonly used in nuclear physics Nuclear physics is the field of physics Physics is the natural science that studies ...
of 87 days and formed in
cosmic ray spallation Cosmic ray spallation, also known as the x-process, is a set of naturally occurring nuclear reactions causing nucleosynthesis Nucleosynthesis is the process that creates new atomic nuclei The atomic nucleus is the small, dense region consistin ...
of 40, the
radioactive 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 s and s ...

radioactive
isotopes of sulfur have half-lives less than 3 hours. When
sulfide mineral The sulfide minerals are a class of s containing (S2−) or (S22−) as the major . Some sulfide minerals are economically important as metal s. The sulfide class also includes the , the , the , the , the bismuthinides, the s and the s.http://w ...
s are precipitated, isotopic equilibration among solids and liquid may cause small differences in the δ34S values of co-genetic minerals. The differences between minerals can be used to estimate the temperature of equilibration. The δ13C and δ34S of coexisting
carbonate minerals Carbonate minerals are those minerals containing the carbonate ion, CO32−. Carbonate divisions Anhydrous carbonates *Calcite group: trigonal **Calcite CaCO3 **Gaspeite (Ni,Mg,Fe2+)CO3 **Magnesite MgCO3 **Otavite CdCO3 **Rhodochrosite MnCO3 **S ...
and sulfides can be used to determine the and oxygen
fugacity In chemical thermodynamics, the fugacity of a real gas is an effective partial pressure which replaces the mechanical partial pressure in an accurate computation of the chemical equilibrium constant. It is equal to the pressure of an ideal gas w ...
of the ore-bearing fluid during ore formation. In most
forest A forest is an area of land dominated by tree In botany, a tree is a perennial plant with an elongated Plant stem, stem, or trunk (botany), trunk, supporting branches and leaves in most species. In some usages, the definition of a ...

forest
ecosystems, sulfate is derived mostly from the atmosphere; weathering of ore minerals and evaporites contribute some sulfur. Sulfur with a distinctive isotopic composition has been used to identify pollution sources, and enriched sulfur has been added as a tracer in
hydrologic Hydrology (from Greek: ὕδωρ, "hýdōr" meaning "water" and λόγος ''Logos'' (, ; grc, λόγος, lógos; from , , ) is a term in Western philosophy Western philosophy refers to the philosophy, philosophical thought and work of ...
studies. Differences in the
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
s can be used in systems where there is sufficient variation in the 34S of ecosystem components.
Rocky Mountain The Rocky Mountains, also known as the Rockies, are a major mountain range in western North America. The Rocky Mountains stretch in great-circle distance, straight-line distance from the northernmost part of British Columbia, in western Canada, ...

Rocky Mountain
lakes thought to be dominated by atmospheric sources of sulfate have been found to have characteristic 34S values from lakes believed to be dominated by watershed sources of sulfate.


Natural occurrence

32S is created inside massive stars, at a depth where the temperature exceeds 2.5×109 K, by the fusion of one nucleus of silicon plus one nucleus of helium. As this nuclear reaction is part of the
alpha process The alpha process, also known as the alpha ladder, is one of two classes of nuclear fusion reactions by which stars convert helium into heavier elements, the other being the triple-alpha process. The triple-alpha process consumes only helium, and ...
that produces elements in abundance, sulfur is the 10th most common element in the universe. Sulfur, usually as sulfide, is present in many types of
meteorite A meteorite is a solid piece of debris from an object, such as a comet A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces ...
s. Ordinary chondrites contain on average 2.1% sulfur, and carbonaceous chondrites may contain as much as 6.6%. It is normally present as
troilite Troilite is a rare 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 period ...
(FeS), but there are exceptions, with carbonaceous chondrites containing free sulfur, sulfates and other sulfur compounds. The distinctive colors of
Jupiter Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a gas giant A gas giant is a giant planet composed mainly of hydrogen Hydrogen is the chemical element with the Symbol (chemistry), symbol H and at ...

Jupiter
's
volcanic A volcano is a rupture in the crust of a planetary-mass object A planet is an astronomical body orbit In physics, an orbit is the gravitationally curved trajectory of an physical body, object, such as the trajectory of a planet ar ...

volcanic
moon Io are attributed to various forms of molten, solid, and gaseous sulfur. It is the fifth most common element by mass in the Earth. Elemental sulfur can be found near
hot spring A hot spring, hydrothermal spring, or geothermal spring is a spring Spring(s) may refer to: Common uses * Spring (season), a season of the year * Spring (device), a mechanical device that stores energy * Spring (hydrology), a natural source of w ...

hot spring
s and
volcanic A volcano is a rupture in the crust of a planetary-mass object A planet is an astronomical body orbit In physics, an orbit is the gravitationally curved trajectory of an physical body, object, such as the trajectory of a planet ar ...

volcanic
regions in many parts of the world, especially along the
Pacific Ring of Fire The Ring of Fire (also known as the Pacific Ring of Fire, the Rim of Fire, the Girdle of Fire or the Circum-Pacific belt) is a region around much of the rim of the Pacific Ocean where many Types of volcanic eruptions, volcanic eruptions and e ...

Pacific Ring of Fire
; such volcanic deposits are currently mined in Indonesia, Chile, and Japan. These deposits are polycrystalline, with the largest documented single crystal measuring 22×16×11 cm. Historically,
Sicily (man) it, Siciliana (woman) , population_note = , population_blank1_title = , population_blank1 = , demographics_type1 = Ethnicity , demographics1_footnotes = , demographi ...

Sicily
was a major source of sulfur in the
Industrial Revolution The Industrial Revolution was the transition to new manufacturing processes in Great Britain, continental Europe Continental Europe or mainland Europe is the contiguous continent A continent is any of several large landmasse ...
. Lakes of molten sulfur up to ~200 m in diameter have been found on the sea floor, associated with
submarine volcano Submarine volcanoes are underwater vents or fissures in the Earth Earth is the third planet from the Sun and the only astronomical object known to harbour and support life. 29.2% of Earth's surface is land consisting of continents and ...
es, at depths where the boiling point of water is higher than the melting point of sulfur.C. E. J. de Ronde, W. W. Chadwick Jr, R. G. Ditchburn, R. W. Embley, V. Tunnicliffe, E. T. Baker. S. L. Walker. V. L. Ferrini, and S. M. Merle (2015): "Molten Sulfur Lakes of Intraoceanic Arc Volcanoes". Chapter of ''Volcanic Lakes'' (Springer), pages 261-288. Native sulfur is synthesised by
anaerobic bacteria An anaerobic organism or anaerobe is any organism that does not require oxygen for growth. It may react negatively or even die if free oxygen is present. In contrast, an aerobic organism (aerobe) is an organism that requires an oxygenated environme ...

anaerobic bacteria
acting on
sulfate minerals The sulfate minerals are a class of mineral 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), ...

sulfate minerals
such as
gypsum Gypsum is a soft sulfate mineral The sulfate minerals are a class of mineral In geology Geology (from the Ancient Greek γῆ, ''gē'' ("earth") and -λoγία, ''-logia'', ("study of", "discourse")) is an Earth science concerned with ...

gypsum
in
salt dome A salt dome is a type of structural dome formed when salt (or other 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 d ...
s. Significant deposits in salt domes occur along the coast of the
Gulf of Mexico The Gulf of Mexico ( es, Golfo de México) is an ocean basin 400px, Diagrammatic cross-section of an ocean basin, showing the various geographic features In hydrology Hydrology (from Greek: wikt:ὕδωρ, ὕδωρ, "hýdōr" meaning ...

Gulf of Mexico
, and in
evaporite An evaporite () is a water-soluble Solubility is the property of a solid, liquid or gaseous chemical substance called ''solution, solute'' to dissolve in a solid, liquid or gaseous solvent. The solubility of a substance fundamentally depend ...
s in eastern Europe and western Asia. Native sulfur may be produced by geological processes alone. Fossil-based sulfur deposits from salt domes were once the basis for commercial production in the United States, Russia, Turkmenistan, and Ukraine. Currently, commercial production is still carried out in the Osiek mine in Poland. Such sources are now of secondary commercial importance, and most are no longer worked. Common naturally occurring sulfur compounds include the
sulfide minerals The sulfide minerals are a class of mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs na ...
, such as
pyrite The mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. R ...

pyrite
(iron sulfide),
cinnabar Cinnabar () or cinnabarite (), from the grc, κιννάβαρι (), is the bright scarlet to brick-red form of mercury(II) sulfide Mercury sulfide'', or mercury(II) sulfide is a chemical compound composed of the chemical elements mercury (el ...

cinnabar
(mercury sulfide),
galena Galena, also called lead glance, is the natural mineral form of lead(II) sulfide Lead is a chemical element upright=1.0, 500px, The chemical elements ordered by link=Periodic table In chemistry Chemistry is the science, scienti ...

galena
(lead sulfide),
sphalerite Sphalerite is a sulfide mineral The sulfide minerals are a class of s containing (S2−) or (S22−) as the major . Some sulfide minerals are economically important as metal s. The sulfide class also includes the , the , the , the , the bi ...

sphalerite
(zinc sulfide), and
stibnite Stibnite, sometimes called antimonite, is a sulfide mineral with the formula In science Science (from the Latin word ''scientia'', meaning "knowledge") is a systematic enterprise that Scientific method, builds and Taxonomy (general), org ...

stibnite
(antimony sulfide); and the
sulfate minerals The sulfate minerals are a class of mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs na ...
, such as
gypsum Gypsum is a soft sulfate mineral The sulfate minerals are a class of mineral In geology Geology (from the Ancient Greek γῆ, ''gē'' ("earth") and -λoγία, ''-logia'', ("study of", "discourse")) is an Earth science concerned with ...

gypsum
(calcium sulfate),
alunite Alunite is a hydroxylated 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 Ame ...

alunite
(potassium aluminium sulfate), and
barite Baryte, barite or barytes (, ) is a mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs na ...

barite
(barium sulfate). On Earth, just as upon Jupiter's moon Io, elemental sulfur occurs naturally in volcanic emissions, including emissions from
hydrothermal vent A hydrothermal vent is a fissure A fissure is a long, narrow crack opening along the surface of the Earth. It is derived from the Latin word , which means 'cleft' or 'crack'. Fissures emerge in the Earth's crust, on ice sheets and glaciers, and ...
s. The main industrial source of sulfur is now
petroleum Petroleum, also known as crude oil and oil, is a naturally occurring, yellowish-black liquid A liquid is a nearly incompressible In fluid mechanics or more generally continuum mechanics, incompressible flow (isochoric process, isoc ...

petroleum
and
natural gas Natural gas (also called fossil gas; sometimes just gas) is a naturally occurring hydrocarbon gas mixture consisting of methane and commonly including varying amounts of other higher alkanes, and sometimes a small percentage of carbon dioxid ...

natural gas
.


Compounds

Common
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 sulfur range from −2 to +6. Sulfur forms stable compounds with all elements except the
noble gas The noble gases (historically also the inert gases; sometimes referred to as aerogens) make up a class of chemical element In chemistry Chemistry is the study of the properties and behavior of . It is a that covers the that m ...
es.


Allotropes

Sulfur forms over 30 solid
allotropes Allotropy or allotropism () is the property of some 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 o ...
, more than any other element. Besides S8, several other rings are known. Removing one atom from the crown gives S7, which is more of a deep yellow than the S8.
HPLC High-performance liquid chromatography (HPLC), formerly referred to as high-pressure liquid chromatography, is a technique in analytical chemistry Analytical chemistry studies and uses instruments and methods used to separate, identify, and ...

HPLC
analysis of "elemental sulfur" reveals an equilibrium mixture of mainly S8, but with S7 and small amounts of S6. Larger rings have been prepared, including S12 and S18.
Amorphous In condensed matter physics Condensed matter physics is the field of that deals with the macroscopic and microscopic physical properties of , especially the and which arise from forces between s. More generally, the subject deals with " ...

Amorphous
or "plastic" sulfur is produced by rapid cooling of molten sulfur—for example, by pouring it into cold water.
X-ray crystallography X-ray crystallography is the experimental science determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to Diffraction, diffract into many specific directions. By measurin ...

X-ray crystallography
studies show that the amorphous form may have a
helical Helical may refer to: *Helix, the mathematical concept for the shape * Helical spring, a coilspring *Helical plc, a British property company, once a maker of steel bar stock * Helicoil, a mechanical thread repairing insert * H-el-ical//, stage name ...

helical
structure with eight atoms per turn. The long coiled polymeric molecules make the brownish substance elastic, and in bulk this form has the feel of crude rubber. This form is
metastable In chemistry and physics, metastability denotes an intermediate energetic state within a dynamical system other than the system's ground state, state of least energy. A ball resting in a hollow on a slope is a simple example of metastability. I ...
at room temperature and gradually reverts to crystalline molecular allotrope, which is no longer elastic. This process happens within a matter of hours to days, but can be rapidly catalyzed.


Polycations and polyanions

Sulfur polycations, S82+, S42+ and S162+ are produced when sulfur is reacted with mild oxidising agents in a strongly acidic solution. The colored solutions produced by dissolving sulfur in
oleum Oleum (Latin Latin (, or , ) is a classical language A classical language is a language A language is a structured system of communication Communication (from Latin ''communicare'', meaning "to share" or "to be in relation wit ...
were first reported as early as 1804 by C.F. Bucholz, but the cause of the color and the structure of the polycations involved was only determined in the late 1960s. S82+ is deep blue, S42+ is yellow and S162+ is red. The
radical anion In organic chemistry, radical anion is a subset of charged free radical Free may refer to: Concept * Freedom Freedom, generally, is having the ability to act or change without constraint. Something is "free" if it can change easily and is no ...
S3 gives the blue color of the mineral
lapis lazuli Lapis lazuli (; ), or lapis for short, is a deep-blue metamorphic rock , a type of metamorphic rock Metamorphic rocks arise from the transformation of existing rock (geology), rock to new types of rock, in a process called metamorphism up ...

lapis lazuli
.


Sulfides

Treatment of sulfur with hydrogen gives
hydrogen sulfide Hydrogen sulfide is a 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 havi ...

hydrogen sulfide
. When dissolved in water, hydrogen sulfide is mildly acidic:Greenwood, N. N.; & Earnshaw, A. (1997). Chemistry of the Elements (2nd ed.), Oxford:Butterworth-Heinemann. . :H2S HS + H+ Hydrogen sulfide gas and the hydrosulfide anion are extremely toxic to mammals, due to their inhibition of the oxygen-carrying capacity of hemoglobin and certain
cytochrome Cytochromes are redox-active protein Proteins are large biomolecule , showing alpha helices, represented by ribbons. This poten was the first to have its suckture solved by X-ray crystallography by Max Perutz and Sir John Cowdery Kendr ...
s in a manner analogous to
cyanide A cyanide 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 che ...

cyanide
and
azide Azide 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 tha ...

azide
(see below, under ''precautions''). Reduction of elemental sulfur gives
polysulfide Polysulfides are a class of 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 ...

polysulfide
s, which consist of chains of sulfur atoms terminated with S centers: :2 Na + S8 → Na2S8 This reaction highlights a distinctive property of sulfur: its ability to catenate (bind to itself by formation of chains).
Protonation In chemistry, protonation (or hydronation) is the addition of a proton (or hydron, or hydrogen cation), (H+) to an atom An atom is the smallest unit of ordinary matter In classical physics and general chemistry, matter is any substance ...
of these polysulfide anions produces the
polysulfaneA polysulfane 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 chemic ...
s, H2Sx where x= 2, 3, and 4. Ultimately, reduction of sulfur produces sulfide salts: :16 Na + S8 → 8 Na2S The interconversion of these species is exploited in the
sodium–sulfur battery A sodium–sulfur battery is a type of molten-salt battery 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 a ...
.


Oxides, oxoacids, and oxoanions

The principal sulfur oxides are obtained by burning sulfur: :S + O2 → SO2 (
sulfur dioxide Sulfur dioxide (IUPAC The International Union of Pure and Applied Chemistry (IUPAC ) is an international federation of National Adhering OrganizationsNational Adhering Organizations in chemistry are the organizations that work as the autho ...
) :2 SO2 + O2 → 2 SO3 (
sulfur trioxide Sulfur trioxide (alternative spelling sulphur trioxide, also known as ''nisso sulfan'') is the chemical compound with the formula SO3. It has been described as "unquestionably the most important economically" sulfur oxide. It is prepared on an ind ...
) Multiple sulfur oxides are known; the sulfur-rich oxides include sulfur monoxide, disulfur monoxide, disulfur dioxides, and higher oxides containing peroxo groups. Sulfur forms
sulfur oxoacidsThe ''sulfur oxoacids'' are chemical compounds that contain sulfur, oxygen, and hydrogen. The best known and most important industrially used is sulfuric acid. Sulfur has several oxoacids; however, some of these are known only from their salts (these ...
, some of which cannot be isolated and are only known through the salts.
Sulfur dioxide Sulfur dioxide (IUPAC The International Union of Pure and Applied Chemistry (IUPAC ) is an international federation of National Adhering OrganizationsNational Adhering Organizations in chemistry are the organizations that work as the autho ...
and
sulfite Sulfites or sulphites are compounds 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 ...

sulfite
s () are related to the unstable
sulfurous acid Sulfurous acid (also Sulfuric(IV) acid, Sulphurous acid (UK), Sulphuric(IV) acid (UK)) is the chemical compound with the chemical formula, formula H2SO3. There is no evidence that sulfurous acid exists in solution, but the molecule has been det ...

sulfurous acid
(H2SO3).
Sulfur trioxide Sulfur trioxide (alternative spelling sulphur trioxide, also known as ''nisso sulfan'') is the chemical compound with the formula SO3. It has been described as "unquestionably the most important economically" sulfur oxide. It is prepared on an ind ...
and
sulfate The sulfate or sulphate ion is a polyatomic 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 ...

sulfate
s () are related to
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 orthogra ...

sulfuric acid
(H2SO4). Sulfuric acid and SO3 combine to give oleum, a solution of (H2S2O7) in sulfuric acid.
Thiosulfate Thiosulfate () (IUPAC-recommended spelling; sometimes thiosulphate in British English) is an Sulfur oxoacid, oxyanion of sulfur. The prefix thio- indicates that the thiosulfate ion is a sulfate ion with one oxygen replaced by sulfur. Thiosulfate h ...
salts (), sometimes referred as "hyposulfites", used in photographic fixing (hypo) and as reducing agents, feature sulfur in two oxidation states.
Sodium dithionite Sodium dithionite (also known as sodium hydrosulfite) is a white crystalline powder with a sulfurous odor. Although it is stable in dry air, it Chemical decomposition, decomposes in hot water and in acid Solution (chemistry), solutions. Structur ...
(), contains the more highly reducing
dithionite Image:Dithionite-ion-3D-balls.png, 200px, A ball-and-stick model of the dithionite ion. The dithionite is the oxoanion with the formula 2O4−. It is commonly encountered as the salt sodium dithionite. For historial reasons, it is sometime ...

dithionite
anion ().


Halides and oxyhalides

Several sulfur halides are important to modern industry.
Sulfur hexafluoride Sulfur hexafluoride (SF6) or sulphur hexafluoride (British 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 Engli ...
is a dense gas used as an insulator gas in high voltage
transformer A transformer is a passive component that transfers electrical energy from one electrical circuit to another circuit, or multiple Electrical network, circuits. A varying current in any one coil of the transformer produces a varying magnetic flux ...

transformer
s; it is also a nonreactive and nontoxic propellant for pressurized containers.
Sulfur tetrafluoride Sulfur tetrafluoride 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 toge ...

Sulfur tetrafluoride
is a rarely-used organic reagent that is highly toxic.
Sulfur dichloride Sulfur dichloride 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 b ...

Sulfur dichloride
and
disulfur dichloride Disulfur dichloride is the inorganic compound of sulfur Sulfur (in traditional laity, lay Commonwealth English: sulphur) is a chemical element with the Symbol (chemistry), symbol S and atomic number 16. It is abundance of the chem ...
are important industrial chemicals.
Sulfuryl chloride Sulfuryl chloride is an inorganic compound with the formula SO2Cl2. At room temperature, it is a colorless liquid with a pungent odor. Sulfuryl chloride is not found in nature, as can be inferred from its rapid hydrolysis. Sulfuryl chloride is ...

Sulfuryl chloride
and
chlorosulfuric acid Chlorosulfuric acid (IUPAC The International Union of Pure and Applied Chemistry (IUPAC ) is an international federation of National Adhering Organizations that represents chemists in individual countries. It is a member of the International S ...

chlorosulfuric acid
are derivatives of sulfuric acid;
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
(SOCl2) is a common reagent in
organic synthesis Organic synthesis is a special branch of chemical synthesis As a topic of , chemical synthesis (or combination) is the artificial execution of s to obtain one or several s. This occurs by and chemical manipulations usually involving one or mo ...

organic synthesis
.


Pnictides

An important S–N compound is the cage
tetrasulfur tetranitride Tetrasulfur tetranitride is an inorganic compound with the chemical formula, formula S4N4. This gold-poppy coloured solid is the most important binary sulfur nitride, which are compounds that contain only the chemical element, elements sulfur and n ...
(). Heating this compound gives polymeric sulfur nitride (), which has metallic properties even though it does not contain any
metal A metal (from Greek#REDIRECT Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country located in Southeast Europe. Its population is appro ...

metal
atoms.
Thiocyanate Thiocyanate (also known as rhodanide) 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 ...
s contain the group. Oxidation of thiocyanate gives thiocyanogen, with the connectivity . Phosphorus sulfides are numerous, the most important commercially being the cages and .


Metal sulfides

The principal ores of copper, zinc, nickel, cobalt, molybdenum, and other metals are sulfides. These materials tend to be dark-colored semiconductors that are not readily attacked by water or even many acids. They are formed, both geochemical cycle, geochemically and in the laboratory, by the reaction of hydrogen sulfide with metal salts. The mineral
galena Galena, also called lead glance, is the natural mineral form of lead(II) sulfide Lead is a chemical element upright=1.0, 500px, The chemical elements ordered by link=Periodic table In chemistry Chemistry is the science, scienti ...

galena
(PbS) was the first demonstrated semiconductor and was used as a signal rectifier in the cat's-whisker detector, cat's whiskers of early crystal radios. The iron sulfide called
pyrite The mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. R ...

pyrite
, the so-called "fool's gold", has the formula FeS2. Processing these ores, usually by Smelting#Roasting, roasting, is costly and environmentally hazardous. Sulfur corrodes many metals through tarnishing.


Organic compounds

File:Allicin skeletal.svg, Allicin, a chemical compound in garlic File:L-Cystein - L-Cysteine.svg , (''R'')-
cysteine Cysteine (symbol Cys or C; ) is a semiessential proteinogenic amino acid with the chemical formula, formula HOOC-CH-(NH2)-CH2-SH. The thiol side chain in cysteine often participates in enzymatic reactions as a nucleophile. The thiol is suscepti ...

cysteine
, an
amino acid Amino acids are organic compound In , organic compounds are generally any s that contain - . Due to carbon's ability to (form chains with other carbon s), millions of organic compounds are known. The study of the properties, reactions, a ...

amino acid
containing a thiol group File:Methionin - Methionine.svg, Methionine, an
amino acid Amino acids are organic compound In , organic compounds are generally any s that contain - . Due to carbon's ability to (form chains with other carbon s), millions of organic compounds are known. The study of the properties, reactions, a ...

amino acid
containing a thioether File:Diphenyl disulfide.png, Diphenyl disulfide, a representative disulfide File:Perfluorooctanesulfonic acid.png, Perfluorooctanesulfonic acid, a surfactant File:Dibenzothiophen - Dibenzothiophene.svg, Dibenzothiophene, a component of crude oil File:Penicillin core.svg, Penicillin, an antibiotic where "R" is the variable group
Some of the main classes of sulfur-containing organic compounds include the following: * Thiols or mercaptans (so called because they capture mercury as chelation, chelators) are the sulfur analogs of alcohols; treatment of thiols with base gives thiolate ions. * Thioethers are the sulfur analogs of ethers. * Sulfonium ions have three groups attached to a cationic sulfur center. Dimethylsulfoniopropionate (DMSP) is one such compound, important in the marine organic sulfur cycle. * Sulfoxides and sulfones are thioethers with one and two oxygen atoms attached to the sulfur atom, respectively. The simplest sulfoxide, dimethyl sulfoxide, is a common solvent; a common sulfone is sulfolane. * Sulfonic acids are used in many detergents. Compounds with carbon–sulfur multiple bonds are uncommon, an exception being
carbon disulfide Carbon disulfide, also spelled as carbon disulphide, is a colorless volatility (chemistry), volatile liquid with the chemical formula, formula CS2. The Chemical compound, compound is used frequently as a building block in organic chemistry as well ...
, a volatile colorless liquid that is structurally similar to carbon dioxide. It is used as a reagent to make the polymer rayon and many organosulfur compounds. Unlike carbon monoxide, carbon monosulfide is stable only as an extremely dilute gas, found between solar systems. Organosulfur compounds are responsible for some of the unpleasant odors of decaying organic matter. They are widely known as the odorizer, odorant in domestic natural gas, garlic odor, and skunk spray. Not all organic sulfur compounds smell unpleasant at all concentrations: the sulfur-containing terpene, monoterpenoid (grapefruit mercaptan) in small concentrations is the characteristic scent of grapefruit, but has a generic thiol odor at larger concentrations. Sulfur mustard, a potent blister agent, vesicant, was Chemical weapons in World War I, used in World War I as a disabling agent. Sulfur–sulfur bonds are a structural component used to stiffen rubber, similar to the disulfide bridges that rigidify proteins (see biological below). In the most common type of industrial "curing" or hardening and strengthening of natural rubber, elemental sulfur is heated with the rubber to the point that chemical reactions form disulfide bridges between isoprene units of the polymer. This process, patented in 1843, made rubber a major industrial product, especially in automobile tires. Because of the heat and sulfur, the process was named sulfur vulcanization, vulcanization, after the Roman god of the forge and volcanism.


History


Antiquity

Being abundantly available in native form, sulfur was known in ancient times and is referred to in the Torah (Book of Genesis, Genesis). English translations of the Bible, English translations of the Christian Bible commonly referred to burning sulfur as "brimstone", giving rise to the term "fire and brimstone, fire-and-brimstone" sermons, in which listeners are reminded of the fate of Damnation, eternal damnation that await the unbelieving and unrepentant. It is from this part of the Bible that Hell is implied to "smell of sulfur" (likely due to its association with volcanic activity). According to the Ebers Papyrus, a sulfur ointment was used in ancient Egypt to treat granular eyelids. Sulfur was used for fumigation in preclassical Greece; this is mentioned in the ''Odyssey''. Pliny the Elder discusses sulfur in book 35 of his ''Natural History (Pliny), Natural History'', saying that its best-known source is the island of Melos. He mentions its use for fumigation, medicine, and bleaching cloth. A natural form of sulfur known as () was known in China since the 6th century BC and found in Hanzhong. By the 3rd century, the Chinese discovered that sulfur could be extracted from
pyrite The mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. R ...

pyrite
. Chinese Daoists were interested in sulfur's flammability and its reactivity with certain metals, yet its earliest practical uses were found in traditional Chinese medicine. A Song dynasty military treatise of 1044 AD described various formulas for Chinese black powder, which is a mixture of potassium nitrate (), charcoal, and sulfur. It remains an ingredient of gunpowder, black gunpowder. Indian alchemists, practitioners of the "science of chemicals" ( sa, रसशास्त्र, rasaśāstra), wrote extensively about the use of sulfur in alchemical operations with mercury, from the eighth century AD onwards. In the rasa shastra, tradition, sulfur is called "the smelly" (, ). Early European alchemy, alchemists gave sulfur a unique alchemical symbol, a triangle at the top of a cross (🜍). The astrological symbol for 2 Pallas, a crossed spear (⚴), has been published in various forms, including one that looks like the symbol for sulfur. In traditional skin treatment, elemental sulfur was used (mainly in creams) to alleviate such conditions as scabies, ringworm, psoriasis, eczema, and acne. The mechanism of action is unknown—though elemental sulfur does oxidize slowly to sulfurous acid, which is (through the action of
sulfite Sulfites or sulphites are compounds 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 ...

sulfite
) a mild reducing and antibacterial agent.


Modern times

Sulfur appears in a column of fixed (non-acidic) alkali in a chemical table of 1718. Antoine Lavoisier used sulfur in combustion experiments, writing of some of these in 1777. Sulfur deposits in
Sicily (man) it, Siciliana (woman) , population_note = , population_blank1_title = , population_blank1 = , demographics_type1 = Ethnicity , demographics1_footnotes = , demographi ...

Sicily
were the dominant source for more than a century. By the late 18th century, about 2,000 tonnes per year of sulfur were imported into Marseille, France, for the production of
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 orthogra ...

sulfuric acid
for use in the Leblanc process. In Industrial Revolution, industrializing Britain, with the repeal of tariffs on salt in 1824, demand for sulfur from Sicily surged upward. The increasing British control and exploitation of the mining, refining, and transportation of the sulfur, coupled with the failure of this lucrative export to transform Sicily's backward and impoverished economy, led to the Sulfur Crisis of 1840, when Ferdinand II of the Two Sicilies, King Ferdinand II gave a monopoly of the sulfur industry to a French firm, violating an earlier 1816 trade agreement with Britain. A peaceful solution was eventually negotiated by France. In 1867, elemental sulfur was discovered in underground deposits in Louisiana and Texas. The highly successful Frasch process was developed to extract this resource. In the late 18th century, furniture makers used molten sulfur to produce sulfur inlay, decorative inlays in their craft. Because of the
sulfur dioxide Sulfur dioxide (IUPAC The International Union of Pure and Applied Chemistry (IUPAC ) is an international federation of National Adhering OrganizationsNational Adhering Organizations in chemistry are the organizations that work as the autho ...
produced during the process of melting sulfur, the craft of sulfur inlays was soon abandoned. Molten sulfur is sometimes still used for setting steel bolts into drilled concrete holes where high shock resistance is desired for floor-mounted equipment attachment points. Pure powdered sulfur was used as a medicinal tonic and laxative. With the advent of the contact process, the majority of sulfur today is used to make sulfuric acid for a wide range of uses, particularly fertilizer. In recent times, the main source of sulfur has become
petroleum Petroleum, also known as crude oil and oil, is a naturally occurring, yellowish-black liquid A liquid is a nearly incompressible In fluid mechanics or more generally continuum mechanics, incompressible flow (isochoric process, isoc ...

petroleum
and
natural gas Natural gas (also called fossil gas; sometimes just gas) is a naturally occurring hydrocarbon gas mixture consisting of methane and commonly including varying amounts of other higher alkanes, and sometimes a small percentage of carbon dioxid ...

natural gas
. This is due to the requirement to remove sulfur from fuels in order to prevent acid rain, and has resulted in a surplus of sulfur.


Spelling and etymology

''Sulfur'' is derived from the Latin word ', which was Hellenized to ' in the erroneous belief that the Latin word came from Greek. This spelling was later reinterpreted as representing an /f/ sound and resulted in the spelling ', which appears in Latin toward the end of the Classical antiquity, Classical period. The true Greek word for sulfur, , is the source of the international chemical prefix ''thio-''. In 12th-century Anglo-Norman language, Anglo-French, it was '. In the 14th century, the erroneously Hellenized Latin ' was restored in Middle English '. By the 15th century, both full Latin spelling variants ''sulfur'' and ''sulphur'' became common in English. The parallel ''f~ph'' spellings continued in Britain until the 19th century, when the word was standardized as ''sulphur''. On the other hand, ''sulfur'' was the form chosen in the United States, whereas Canada uses both. The International Union of Pure and Applied Chemistry, IUPAC adopted the spelling ''sulfur'' in 1990 or 1971, depending on the source cited, as did the Nomenclature Committee of the Royal Society of Chemistry in 1992, restoring the spelling ''sulfur'' to Britain. Oxford Dictionaries note that "in chemistry and other technical uses ... the ''-f-'' spelling is now the standard form for this and related words in British as well as US contexts, and is increasingly used in general contexts as well."


Production

Sulfur may be found by itself and historically was usually obtained in this form; pyrite has also been a source of sulfur. In volcanic regions in
Sicily (man) it, Siciliana (woman) , population_note = , population_blank1_title = , population_blank1 = , demographics_type1 = Ethnicity , demographics1_footnotes = , demographi ...

Sicily
, in ancient times, it was found on the surface of the Earth, and the "Sicilian method, Sicilian process" was used: sulfur deposits were piled and stacked in brick kilns built on sloping hillsides, with airspaces between them. Then, some sulfur was pulverized, spread over the stacked ore and ignited, causing the free sulfur to melt down the hills. Eventually the surface-borne deposits played out, and miners excavated veins that ultimately dotted the Sicilian landscape with labyrinthine mines. Mining was unmechanized and labor-intensive, with pickmen freeing the ore from the rock, and mine-boys or ''carusu, carusi'' carrying baskets of ore to the surface, often through a mile or more of tunnels. Once the ore was at the surface, it was reduced and extracted in smelting ovens. The conditions in Sicilian sulfur mines were horrific, prompting Booker T. Washington to write "I am not prepared just now to say to what extent I believe in a physical hell in the next world, but a sulphur mine in Sicily is about the nearest thing to hell that I expect to see in this life." Elemental sulfur was extracted from
salt dome A salt dome is a type of structural dome formed when salt (or other 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 d ...
s (in which it sometimes occurs in nearly pure form) until the late 20th century. Sulfur is now produced as a side product of other industrial processes such as in oil refining, in which sulfur is undesired. As a mineral, native sulfur under salt domes is thought to be a fossil mineral resource, produced by the action of anaerobic bacteria on sulfate deposits. It was removed from such salt-dome mines mainly by the Frasch process. In this method, superheated water was pumped into a native sulfur deposit to melt the sulfur, and then compressed air returned the 99.5% pure melted product to the surface. Throughout the 20th century this procedure produced elemental sulfur that required no further purification. Due to a limited number of such sulfur deposits and the high cost of working them, this process for mining sulfur has not been employed in a major way anywhere in the world since 2002. Today, sulfur is produced from petroleum,
natural gas Natural gas (also called fossil gas; sometimes just gas) is a naturally occurring hydrocarbon gas mixture consisting of methane and commonly including varying amounts of other higher alkanes, and sometimes a small percentage of carbon dioxid ...

natural gas
, and related fossil resources, from which it is obtained mainly as
hydrogen sulfide Hydrogen sulfide is a 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 havi ...

hydrogen sulfide
. Organosulfur compounds, undesirable impurities in petroleum, may be upgraded by subjecting them to hydrodesulfurization, which cleaves the C–S bonds: :R-S-R + 2 H2 → 2 RH + H2S The resulting hydrogen sulfide from this process, and also as it occurs in natural gas, is converted into elemental sulfur by the Claus process. This process entails oxidation of some hydrogen sulfide to sulfur dioxide and then the comproportionation of the two: :3 O2 + 2 H2S → 2 SO2 + 2 H2O :SO2 + 2 H2S → 3 S + 2 H2O Owing to the high sulfur content of the Athabasca Oil Sands, stockpiles of elemental sulfur from this process now exist throughout Alberta, Canada. Another way of storing sulfur is as a binder (material), binder for concrete, the resulting product having many desirable properties (see sulfur concrete). Sulfur is still mined from surface deposits in poorer nations with volcanoes, such as Indonesia, and worker conditions have not improved much since Booker T. Washington's days. The world production of sulfur in 2011 amounted to 69 million tonnes (Mt), with more than 15 countries contributing more than 1 Mt each. Countries producing more than 5 Mt are China (9.6), US (8.8), Canada (7.1) and Russia (7.1). Production has been slowly increasing from 1900 to 2010; the price was unstable in the 1980s and around 2010.


Applications


Sulfuric acid

Elemental sulfur is used mainly as a precursor to other chemicals. Approximately 85% (1989) is converted to
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 orthogra ...

sulfuric acid
(hydrogen, H2SO4): :2 S + 3 O2 + 2 H2O → 2 H2SO4 In 2010, the United States produced more sulfuric acid than any other inorganic industrial chemical. The principal use for the acid is the extraction of phosphate ores for the production of fertilizer manufacturing. Other applications of sulfuric acid include oil refining, wastewater processing, and mineral extraction.


Other important sulfur chemistry

Sulfur reacts directly with methane to give
carbon disulfide Carbon disulfide, also spelled as carbon disulphide, is a colorless volatility (chemistry), volatile liquid with the chemical formula, formula CS2. The Chemical compound, compound is used frequently as a building block in organic chemistry as well ...
, which is used to manufacture cellophane and rayon. One of the uses of elemental sulfur is in vulcanization of rubber, where
polysulfide Polysulfides are a class of 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 ...

polysulfide
chains crosslink organic polymers. Large quantities of
sulfite Sulfites or sulphites are compounds 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 ...

sulfite
s are used to bleach (chemical), bleach paper and to preserve dried fruit. Many surfactants and detergents (e.g. sodium lauryl sulfate) are sulfate derivatives. Calcium sulfate, gypsum, (CaSO4·2H2O) is mined on the scale of 100 million tonnes each year for use in Portland cement and fertilizers. When silver-based photography was widespread, sodium and ammonium sodium thiosulfate, thiosulfate were widely used as "fixing agents". Sulfur is a component of gunpowder ("black powder").


Fertilizer

Sulfur is increasingly used as a component of
fertilizer A fertilizer (American English American English (AmE, AE, AmEng, USEng, en-US), sometimes called United States English or U.S. English, is the set of varieties of the English language native to the United States. Currently, American E ...

fertilizer
s. The most important form of sulfur for fertilizer is the mineral calcium sulfate. Elemental sulfur is hydrophobic (not soluble in water) and cannot be used directly by plants. Over time, soil bacteria can convert it to soluble derivatives, which can then be used by plants. Sulfur improves the efficiency of other essential plant nutrients, particularly nitrogen and phosphorus. Biologically produced sulfur particles are naturally hydrophilic due to a biopolymer coating and are easier to disperse over the land in a spray of diluted slurry, resulting in a faster uptake. The botanical requirement for sulfur equals or exceeds the requirement for phosphorus. It is an plant nutrition, essential nutrient for plant growth, root nodule formation of legumes, and immunity and defense systems. Sulfur deficiency has become widespread in many countries in Europe. Because atmospheric inputs of sulfur continue to decrease, the deficit in the sulfur input/output is likely to increase unless sulfur fertilizers are used. Atmospheric inputs of sulfur decrease because of actions taken to limit acid rains.


Fine chemicals

Organosulfur compounds are used in pharmaceuticals, dyestuffs, and agrochemicals. Many drugs contain sulfur; early examples being antibacterial sulfonamide (medicine), sulfonamides, known as ''sulfa drugs''. Sulfur is a part of many bacterial defense molecules. Most β-lactam antibiotics, including the penicillins, cephalosporins and monolactams contain sulfur. Magnesium sulfate, known as Epsom salts when in hydrated crystal form, can be used as a laxative, a bath additive, an exfoliant, magnesium supplement for plants, or (when in dehydrated form) as a desiccant.


Fungicide and pesticide

Elemental sulfur is one of the oldest fungicides and pesticides. "Dusting sulfur", elemental sulfur in powdered form, is a common fungicide for grapes, strawberry, many vegetables and several other crops. It has a good efficacy against a wide range of powdery mildew diseases as well as black spot. In organic production, sulfur is the most important fungicide. It is the only fungicide used in organic agriculture, organically farmed apple production against the main disease apple scab under colder conditions. Biosulfur (biologically produced elemental sulfur with hydrophilic characteristics) can also be used for these applications. Standard-formulation dusting sulfur is applied to crops with a sulfur duster or Aerial application, from a dusting plane. Wettable sulfur is the commercial name for dusting sulfur formulated with additional ingredients to make it water miscibility, miscible. It has similar applications and is used as a
fungicide Fungicides are biocidal 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 hav ...
against mildew and other mold-related problems with plants and soil. Elemental sulfur powder is used as an "organic farming, organic" (i.e., "green")
insecticide Insecticides are substances used to kill insects. They include ovicides and larvicides used against insect Egg (biology), eggs and larvae, respectively. Insecticides are used in agriculture, medicine, Industry (manufacturing), industry and by ...
(actually an acaricide) against ticks and mites. A common method of application is dusting the clothing or limbs with sulfur powder. A diluted solution of lime sulfur (made by combining calcium hydroxide with elemental sulfur in water) is used as a dip for pets to destroy ringworm, ringworm (fungus), mange, and other cutaneous conditions, dermatoses and parasitism, parasites. Sulfur candles of almost pure sulfur were burned to fumigant, fumigate structures and wine barrels, but are now considered too toxic for residences.


Bactericide in winemaking and food preservation

Small amounts of
sulfur dioxide Sulfur dioxide (IUPAC The International Union of Pure and Applied Chemistry (IUPAC ) is an international federation of National Adhering OrganizationsNational Adhering Organizations in chemistry are the organizations that work as the autho ...
gas addition (or equivalent potassium metabisulfite addition) to fermented wine to produce traces of
sulfurous acid Sulfurous acid (also Sulfuric(IV) acid, Sulphurous acid (UK), Sulphuric(IV) acid (UK)) is the chemical compound with the chemical formula, formula H2SO3. There is no evidence that sulfurous acid exists in solution, but the molecule has been det ...

sulfurous acid
(produced when SO2 reacts with water) and its
sulfite Sulfites or sulphites are compounds 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 ...

sulfite
salts in the mixture, has been called "the most powerful tool in winemaking". After the yeast-fermentation stage in winemaking, sulfites absorb oxygen and inhibit aerobic organism, aerobic bacterial growth that otherwise would turn ethanol into acetic acid, souring the wine. Without this preservative step, indefinite refrigeration of the product before consumption is usually required. Similar methods go back into antiquity but modern historical mentions of the practice go to the fifteenth century. The practice is used by large industrial wine producers and small organic wine producers alike. Sulfur dioxide and various sulfites have been used for their antioxidant antibacterial preservative properties in many other parts of the food industry. The practice has declined since reports of an allergy-like reaction of some persons to sulfites in foods.


Pharmaceuticals

Sulfur (specifically
octasulfur Octasulfur is an inorganic 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, behavi ...
, S8) is used in pharmaceutical skin preparations for the treatment of acne and other conditions. It acts as a keratolytic agent and also kills bacteria, fungi, scabies mites, and other parasites. Precipitated sulfur and colloidal sulfur are used, in form of lotions, creams, powders, soaps, and bath additives, for the treatment of acne vulgaris, acne rosacea, and seborrhoeic dermatitis. Common adverse effects include irritation of the skin at the application site, such as dryness, stinging, itching and peeling.: Sulfur topical.


Furniture

Sulfur can be used to create decorative inlays in wooden furniture. After a design has been cut into the wood, molten sulfur is poured in and then scraped away so it is flush. Sulfur inlays were particularly popular in the late 18th and early 19th centuries, notably amongst Pennsylvania German cabinetmakers. The practice soon died out, as less toxic and flammable substances were substituted. However, some modern craftsmen have occasionally revived the technique in the creation of replica pieces.


Biological role

Sulfur is an essential component of all living cell (biology), cells. It is the eighth most abundant element in the human body by weight, about equal in abundance to potassium, and slightly greater than sodium and
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 the periodic table and its properties are mostly intermediate betw ...

chlorine
. A human body contains about 140 grams of sulfur. It is vital for the production of insulin,
keratin Keratin () is one of a family of structural fibrous proteins also known as ''scleroproteins''. Alpha-keratin Alpha-keratin, or α-keratin, is a type of keratin Keratin () is one of a family of fibrous structural proteins known as Scleroprot ...

keratin
and collagen.


Protein and organic cofactors

In plants and animals, the
amino acid Amino acids are organic compound In , organic compounds are generally any s that contain - . Due to carbon's ability to (form chains with other carbon s), millions of organic compounds are known. The study of the properties, reactions, a ...

amino acid
s
cysteine Cysteine (symbol Cys or C; ) is a semiessential proteinogenic amino acid with the chemical formula, formula HOOC-CH-(NH2)-CH2-SH. The thiol side chain in cysteine often participates in enzymatic reactions as a nucleophile. The thiol is suscepti ...

cysteine
and
methionine Methionine (symbol Met or M) () is an essential amino acid An essential amino acid, or indispensable amino acid, is an amino acid that cannot be synthesized from scratch by the organism fast enough to supply its demand, and must therefore come ...

methionine
contain most of the sulfur, and the element is present in all polypeptides, proteins, and enzymes that contain these amino acids. In humans, methionine is an essential amino acid that must be ingested. However, save for the vitamins
biotin Biotin, also called vitamin B7, is one of the B vitamins B vitamins are a class of water-soluble vitamin A vitamin is an organic molecule , CH4; is among the simplest organic compounds. In chemistry, organic compounds are generally any ch ...

biotin
and
thiamine Thiamine, also known as thiamin or vitamin B1, is a vitamin A vitamin is an organic molecule , CH4; is among the simplest organic compounds. In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen ...

thiamine
, cysteine and all sulfur-containing compounds in the human body can be synthesized from methionine. The enzyme sulfite oxidase is needed for the metabolism of methionine and cysteine in humans and animals. Disulfide bonds (S-S bonds) between cysteine residues in peptide chains are very important in protein assembly and structure. These covalent bonds between peptide chains confer extra toughness and rigidity. For example, the high strength of feathers and hair is due in part to the high content of S-S bonds with cysteine and sulfur. Eggs are high in sulfur to nourish feather formation in chicks, and the characteristic odor of rotting eggs is due to
hydrogen sulfide Hydrogen sulfide is a 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 havi ...

hydrogen sulfide
. The high disulfide bond content of hair and feathers contributes to their indigestibility and to their characteristic disagreeable odor when burned. Homocysteine and taurine are other sulfur-containing acids that are similar in structure, but not coded by DNA, and are not part of the primary structure of proteins. Many important cellular enzymes use prosthetic groups ending with -SH moieties to handle reactions involving acyl-containing biochemicals: two common examples from basic metabolism are coenzyme A and alpha-lipoic acid. Two of the 13 classical vitamins,
biotin Biotin, also called vitamin B7, is one of the B vitamins B vitamins are a class of water-soluble vitamin A vitamin is an organic molecule , CH4; is among the simplest organic compounds. In chemistry, organic compounds are generally any ch ...

biotin
, and
thiamine Thiamine, also known as thiamin or vitamin B1, is a vitamin A vitamin is an organic molecule , CH4; is among the simplest organic compounds. In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen ...

thiamine
, contain sulfur, with the latter being named for its sulfur content. In intracellular chemistry, sulfur operates as a carrier of reducing hydrogen and its electrons for cellular repair of oxidation. Reduced
glutathione Glutathione (GSH) is an antioxidant Antioxidants are that inhibit , a that can produce and s that may damage the of organisms. Antioxidants such as s or (vitamin C) may act to inhibit these reactions. To balance , plants and animals ma ...

glutathione
, a sulfur-containing tripeptide, is a reducing agent through its sulfhydryl (-SH) moiety derived from
cysteine Cysteine (symbol Cys or C; ) is a semiessential proteinogenic amino acid with the chemical formula, formula HOOC-CH-(NH2)-CH2-SH. The thiol side chain in cysteine often participates in enzymatic reactions as a nucleophile. The thiol is suscepti ...

cysteine
. The
thioredoxin Thioredoxin is a class of small redox protein Proteins are large biomolecules or macromolecules that are comprised of one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within orga ...
s, a class of small proteins essential to all known life, use neighboring pairs of reduced cysteines to work as general protein reducing agents, with similar effect. Methanogenesis, the route to most of the world's methane, is a multistep biochemical transformation of carbon dioxide. This conversion requires several organosulfur cofactors. These include coenzyme M, CH3SCH2CH2SO3, the immediate precursor to methane.


Metalloproteins and inorganic cofactors

Metalloproteins in which the active site is a transition metal complex bound to sulfur atoms are essential components of enzymes involved in electron transfer processes. Examples include blue copper proteins and nitrous-oxide reductase, nitrous oxide reductase. The function of these enzymes is dependent on the fact that the transition metal ion can undergo redox reactions. Other examples include iron–sulfur clusters as well as many copper, nickel, and iron proteins. Most pervasive are the ferrodoxins, which serve as electron shuttles in cells. In bacteria, the important nitrogenase enzymes contains an Fe–Mo–S cluster and is a catalyst that performs the important function of nitrogen fixation, converting atmospheric nitrogen to ammonia that can be used by microorganisms and plants to make proteins, DNA, RNA, alkaloids, and the other organic nitrogen compounds necessary for life. :


Sulfur metabolism and the sulfur cycle

The sulfur cycle was the first of the biogeochemical cycles to be discovered. In the 1880s, while studying Beggiatoa (a bacterium living in a sulfur rich environment), Sergei Winogradsky found that it oxidized
hydrogen sulfide Hydrogen sulfide is a 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 havi ...

hydrogen sulfide
(H2S) as an energy source, forming intracellular sulfur droplets. Winogradsky referred to this form of metabolism as inorgoxidation (oxidation of inorganic compounds). He continued to study it together with Selman Waksman until the 1950s. Sulfur oxidizers can use as energy sources reduced sulfur compounds, including hydrogen sulfide, elemental sulfur,
sulfite Sulfites or sulphites are compounds 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 ...

sulfite
, thiosulfate, and various polythionates (e.g., tetrathionate). They depend on enzymes such as sulfur dioxygenase, sulfur oxygenase and sulfite oxidase to oxidize sulfur to sulfate. Some lithotrophs can even use the energy contained in sulfur compounds to produce sugars, a process known as chemosynthesis. Some bacteria and archaea use hydrogen sulfide in place of water as the electron donor in chemosynthesis, a process similar to photosynthesis that produces sugars and utilizes oxygen as the electron acceptor. The photosynthesis, photosynthetic green sulfur bacteria and purple sulfur bacteria and some lithotrophs use elemental oxygen to carry out such oxidization of hydrogen sulfide to produce elemental sulfur (S0), oxidation state= 0. Primitive bacteria that live around deep ocean hydrothermal vent, volcanic vents oxidize hydrogen sulfide, as discovered by Robert Ballard; the giant tube worm is an example of a large organism that uses hydrogen sulfide (via bacteria) as food to be oxidized. The so-called sulfate-reducing bacteria, by contrast, "breathe sulfate" instead of oxygen. They use organic compounds or molecular hydrogen as the energy source. They use sulfur as the electron acceptor, and reduce various oxidized sulfur compounds back into sulfide, often into hydrogen sulfide. They can grow on other partially oxidized sulfur compounds (e.g. thiosulfates, thionates, polysulfides, sulfites). The hydrogen sulfide produced by these bacteria is responsible for some of the smell of intestinal gases (flatus) and decomposition products. Sulfur is absorbed by plants roots from soil as
sulfate The sulfate or sulphate ion is a polyatomic 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 ...

sulfate
and transported as a phosphate ester. Sulfate is reduced to sulfide via sulfite before it is incorporated into
cysteine Cysteine (symbol Cys or C; ) is a semiessential proteinogenic amino acid with the chemical formula, formula HOOC-CH-(NH2)-CH2-SH. The thiol side chain in cysteine often participates in enzymatic reactions as a nucleophile. The thiol is suscepti ...

cysteine
and other organosulfur compounds. :SO42− → SO32− → H2S → cysteine → methionine


Precautions

Elemental sulfur is non-toxic, as are most of the soluble
sulfate The sulfate or sulphate ion is a polyatomic 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 ...

sulfate
salts, such as Epsom salts. Soluble sulfate salts are poorly absorbed and laxative. When injected parenterally, they are freely filtered by the kidneys and eliminated with very little toxicity in multi-gram amounts. Aluminium sulfate is used in the purification of drinking water, wastewater treatment plants and papermaking. When sulfur burns in air, it produces
sulfur dioxide Sulfur dioxide (IUPAC The International Union of Pure and Applied Chemistry (IUPAC ) is an international federation of National Adhering OrganizationsNational Adhering Organizations in chemistry are the organizations that work as the autho ...
. In water, this gas produces sulfurous acid and sulfites; sulfites are antioxidants that inhibit growth of aerobic bacteria and a useful food additive in small amounts. At high concentrations these acids harm the human lungs, lungs, human eyes, eyes, or other biological tissue, tissues. In organisms without lungs such as insects or plants, sulfite in high concentration prevents respiration (physiology), respiration.
Sulfur trioxide Sulfur trioxide (alternative spelling sulphur trioxide, also known as ''nisso sulfan'') is the chemical compound with the formula SO3. It has been described as "unquestionably the most important economically" sulfur oxide. It is prepared on an ind ...
(made by catalysis from sulfur dioxide) and
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 orthogra ...

sulfuric acid
are similarly highly acidic and corrosive in the presence of water. Sulfuric acid is a strong dehydrating agent that can strip available water molecules and water components from sugar and organic tissue. The burning of coal and/or
petroleum Petroleum, also known as crude oil and oil, is a naturally occurring, yellowish-black liquid A liquid is a nearly incompressible In fluid mechanics or more generally continuum mechanics, incompressible flow (isochoric process, isoc ...

petroleum
by industry and power plants generates sulfur dioxide (SO2) that reacts with atmospheric water and oxygen to produce sulfuric acid (H2SO4) and
sulfurous acid Sulfurous acid (also Sulfuric(IV) acid, Sulphurous acid (UK), Sulphuric(IV) acid (UK)) is the chemical compound with the chemical formula, formula H2SO3. There is no evidence that sulfurous acid exists in solution, but the molecule has been det ...

sulfurous acid
(H2SO3). These acids are components of acid rain, lowering the of soil and freshwater bodies, sometimes resulting in substantial damage to the environment (biophysical), environment and chemical weathering of statues and structures. Fuel standards increasingly require that fuel producers extract sulfur from fossil fuels to prevent acid rain formation. This extracted and refined sulfur represents a large portion of sulfur production. In coal-fired power plants, flue gases are sometimes purified. More modern power plants that use synthesis gas extract the sulfur before they burn the gas.
Hydrogen sulfide Hydrogen sulfide is a 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 havi ...

Hydrogen sulfide
is as toxic as hydrogen cyanide, and kills by the same mechanism (inhibition of the respiratory enzyme cytochrome oxidase), though hydrogen sulfide is less likely to cause surprise poisonings from small inhaled amounts because of its disagreeable odor. Hydrogen sulfide quickly deadens the sense of smell and a victim may breathe increasing quantities without noticing the increase until severe symptoms cause death. Dissolved sulfide and hydrosulfide salts are toxic by the same mechanism.


See also

*Blue lava *Stratospheric sulfur aerosols *Sulfur assimilation *Ultra-low sulfur diesel


References


Further reading


External links


Sulfur
at ''The Periodic Table of Videos'' (University of Nottingham)
Atomic Data for Sulfur
NIST Physical Measurement Laboratory
Sulfur phase diagram
Introduction to Chemistry for Ages 13–17

*[http://extoxnet.orst.edu/pips/sulfur.htm Sulfur and its use as a pesticide]
The Sulphur InstituteNutrient Stewardship and The Sulphur Institute
{{Authority control Sulfur, Chemical elements Chalcogens Reactive nonmetals Polyatomic nonmetals Agricultural chemicals Anti-acne preparations Biology and pharmacology of chemical elements Dietary minerals Industrial minerals Inorganic polymers Native element minerals Orthorhombic minerals Minerals in space group 70 Pyrotechnic fuels Chemical elements with primitive orthorhombic structure