Sulfur

History

 

Sulfur (Sanskrit, sulvari; Latin sulfur or sulpur) was known in ancient times, and is referred to in the Biblical Pentateuch (Genesis).

English translations of the Bible commonly referred to sulfur as "brimstone", giving rise to the name of 'Fire and brimstone' sermons, in which listeners are reminded of the fate of eternal damnation that awaits the unbelieving and unrepentant. It is from this part of the Bible that Hell is implied to "smell of sulfur", although as mentioned above sulfur is in fact odorless. The "smell of sulfur" usually refers to either the odor of sulfur dioxide, the smell associated with burnt matches.

Sulfur was known in China since the 6th century BC, in a natural form that the Chinese had called 'brimstone', or shiliuhuang that was found in Hanzhong.^[1] By the 3rd century, the Chinese discovered that sulfur could be extracted from alchemical symbol which was a triangle at the top of a cross.

In the late 1770s, Antoine Lavoisier helped convince the scientific community that sulfur was an element and not a compound. In 1867, sulfur was discovered in underground deposits in Louisiana and Texas. The overlying layer of earth was quicksand, prohibiting ordinary mining operations, therefore the Frasch process was used.

Spelling

The element has traditionally been spelled sulphur in the United Kingdom, Ireland, Hong Kong, the Commonwealth Caribbean and India, but sulfur in the United States, while both spellings are used in Australia, New Zealand and Canada. IUPAC adopted the spelling “sulfur” in 1990, as did the Royal Society of Chemistry Nomenclature Committee in 1992^[2] and the Qualifications and Curriculum Authority for England and Wales recommended its use in 2000.^[3] The spelling of the term in non-official texts is gradually becoming uniform as sulfur.

In Latin, the word is variously written sulpur, sulphur, and sulfur (the Oxford Latin Dictionary lists the spellings in this order). It is an original Latin name and not a Classical Greek loan, so the ph variant does not denote the Greek letter φ. Sulfur in Greek is theion (θεῖον), whence comes the prefix thio-. The simplification of the Latin word's p or ph to an f appears to have taken place towards the end of the classical period, with the f spelling becoming dominant in the medieval period. ^[4]

Isotopes

Main article: Isotopes of sulfur

Sulfur has 18 half-life of 87 days.

When sulfide fugacity of the ore-bearing fluid during ore formation.

In most forest ecosystems, sulfate is derived mostly from the atmosphere; weathering of ore minerals and evaporites also 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 studies. Differences in the natural abundances can also be used in systems where there is sufficient variation in the ³⁴S of ecosystem components. Rocky Mountain lakes thought to be dominated by atmospheric sources of sulfate have been found to have different δS-34 values from lakes believed to be dominated by watershed sources of sulfate.

Allotropes

Main article: Allotropes of sulfur

Sulfur forms more than 30 solid Selenium, the heavier analogue of sulfur can form rings but is more often found as a polymer chain.

Occurrence

    Elemental sulfur can be found near hot springs and volcanic regions in many parts of the world, especially along the Pacific Ring of Fire. Such volcanic deposits are currently mined in Indonesia, Chile, and Japan. Sicily is also famous for its sulfur mines.

Significant deposits of elemental sulfur also exist in salt domes along the coast of the Gulf of Mexico, and in gypsum, although apparently native sulfur may be produced by geological processes alone, without the aid of living organisms (see below). However, fossil-based sulfur deposits from salt domes are the basis for commercial production in the United States, Poland, Russia, Turkmenistan, and Ukraine.

Sulfur production through Athabasca Oil Sands has produced a surplus - huge stockpiles of sulfur now exist throughout Alberta, Canada.

Common naturally occurring sulfur compounds include the barite (barium sulfate). It occurs naturally in volcanic emissions, such as from hydrothermal vents, and from bacterial action on decaying sulfur-containing organic matter.

The distinctive colors of Jupiter's volcanic moon, Io, are from various forms of molten, solid and gaseous sulfur. There is also a dark area near the Lunar crater Aristarchus that may be a sulfur deposit.

Sulfur is present in many types of meteorites. Ordinary chondrites contain on average 2.1% sulfur, and carbonaceous chondrites may contain as much as 6.6%. Sulfur in meteorites is normally present entirely as troilite (FeS), but other sulfides are found in some meteorites, and carbonaceous chondrites contain free sulfur, sulfates, and possibly other sulfur compounds.^[10]

Notable characteristics

  At room temperature, sulfur is a soft bright yellow solid. Elemental sulfur has only a faint odor, similar to that of matches. The odor associated with rotten eggs is due to hydrogen sulfide (H₂S) and organic sulfur compounds rather than elemental sulfur. Sulfur burns with a blue flame that emits noble gases. Sulfur in the solid state ordinarily exists as cyclic crown-shaped S₈ molecules.

  The monoclinic S₈ best known.

A noteworthy property of sulfur is that its polymers. The molten sulfur assumes a dark red color above this temperature. At higher temperatures, however, the viscosity is decreased as depolymerization occurs.

metastable at room temperature and gradually reverts back to crystalline form. This process happens within a matter of hours to days but can be rapidly catalyzed.

Extraction

Sulfur is extracted by mainly two processes: the Sicilian process and the Frasch process. The Sicilian process, which was first used in Sicily, was used in ancient times to get sulfur from rocks present in volcanic regions. In this process, the sulfur deposits are piled and stacked in brick kilns built on sloping hillsides, and with airspaces between them. Then powdered sulfur is put on top of the sulfur deposit and ignited. As the sulfur burns, the heat melts the sulfur deposits, causing the molten sulfur to flow down the sloping hillside. The molten sulfur can then be collected in wooden buckets.

The second process used to obtain sulfur is the Frasch process. In this method, three concentric pipes are used: the outermost pipe contains superheated water, which melts the sulfur, and the innermost pipe is filled with hot compressed air, which serves to create foam and pressure. The resulting sulfur foam is then expelled through the middle pipe.

The Frasch process produces sulfur with a 99.5% purity content, and which needs no further purification. The sulfur produced by the Sicilian process must be purified by distillation.

The hydrodesulfurization of petroleum or from natural gas.

Compounds

  semiconductor discovered, and found a use as a signal rectifier in the "cat's whiskers" of early crystal radios.

Many of the unpleasant odors of organic matter are based on sulfur-containing compounds such as monoterpenoid is responsible for the characteristic scent of grapefruit.

Polymeric sulfur nitride has metallic properties even though it does not contain any tetrasulfur tetranitride S₄N₄.

Phosphorus sulfides are useful in synthesis. For example, P₄S₁₀ and its derivatives naphthalen-1,8-diyl 1,3,2,4-dithiadiphosphetane 2,4-disulfide are used to replace oxygen from some organic molecules with sulfur.

Inorganic sulfur compounds:  

• Sulfides (S²⁻), a complex family of compounds usually derived from S²⁻. Cadmium sulfide (CdS) is an example.
• Sulfites (SO₃²⁻), the salts of sulfurous acid (H₂SO₃) which is generated by dissolving SO₂ in water. Sulfurous acid and the corresponding sulfites are fairly strong reducing agents. Other compounds derived from SO₂ include the pyrosulfite or metabisulfite ion (S₂O₅²⁻).
• sulfuric acid. Sulfuric acid also reacts with SO₃ in equimolar ratios to form pyrosulfuric acid (H₂S₂O₇).
• gold.[2]
• Sodium dithionite, Na₂S₂O₄, is the highly reducing dianion derived from hyposulfurous/dithionous acid.
• Sodium dithionate (Na₂S₂O₆).
• Polythionic acids (H₂S_nO₆), where n can range from 3 to 80.
• H₂SO₄ on concentrated H₂O₂ respectively.
• Sodium polysulfides (Na₂S_x)
• Sulfur hexafluoride, SF₆, a dense gas at ambient conditions, is used as nonreactive and nontoxic propellant
• Sulfur nitrides are chain and cyclic compounds containing only S and N. Tetrasulfur tetranitride S₄N₄ is an example.
• Thiocyanates contain the SCN⁻ group. Oxidation of thiocyanoate gives thiocyanogen, (SCN)₂ with the connectivity NCS-SCN.

Organic sulfur compounds (where R, R', and R are organic groups such as CH₃):  

• ethers.
• Sulfonium ions have the formula RR'S-'R'", i.e. where three groups are attached to the cationic sulfur center. sulfur cycle.
• Thiols (also known as mercaptans) have the form R-SH. These are the sulfur equivalents of alcohols.
• thiols with base.
• DMSO.
• Sulfones have the form R-S(=O)₂-R′. A common sulfone is sulfolane C₄H₈SO₂.

See also organosulfur chemistry

Applications

One of the direct uses of sulfur is in rayon.^[12]

Elemental sulfur is mainly used as a precursor to other chemicals. Approximately 85% (1989) is converted to O₄), which is of such prime importance to the world's economies that the production and consumption of sulfuric acid is an indicator of a nation's industrial development.[3]. For example, more sulfuric acid is produced in the United States every year than any other 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.^[12]

Sulfur compounds are also used in detergents, fungicides, dyestuffs, and agrichemicals. In silver-based photography sodium and ammonium thiosulfate are used as "fixing agents."

Sulfites, derived from burning sulfur, is heavily used to bleach paper. It is also a preservative in dried fruit.

desiccant.

Specialized applications

Sulfur is used as a light-generating medium in the rare lighting fixtures known as sulfur lamps.

Historical applications

In the late 18th century, furniture makers used molten sulfur to produce decorative inlays in their craft. Because of the sulfur dioxide 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 also used as a medicinal tonic and laxative.

Biological role

Sulfur is an essential component of all living cells.

Sulfur may also serve as chemical food source for some primitive organisms: some forms of bacteria use cytochrome c oxidase, a basic substance involved in utilization of oxygen by all aerobic life.

Sulfur is absorbed by plants via the roots from soil as the sulfur assimilation).

In plants and animals the alpha-lipoic acid.

Disulfide bonds (S-S bonds) formed between cysteine residues in peptide chains are very important in protein assembly and structure. These strong covalent bonds between peptide chains give proteins a great deal of extra toughness and resiliency. For example, the high strength of feathers and hair is in part due to their high content of S-S bonds and their high content of cysteine and sulfur (eggs are high in sulfur because large amounts of the element are necessary for feather formation). The high disulfide content of hair and feathers contributes to their indigestibility, and also their odor when burned.

Traditional medical role for elemental sulfur

In traditional medical skin treatment which predates modern era of scientific medicine, elmental sulfur has been used mainly as part of cremes to alleviate various conditions such as psoriasis, eczema & acne. The mechanism of action is not known, although elemental sulfur does oxidize slowly to sulfurous acid, which in turn (though the action of sulfite) acts as a mild reducing and antibacterial agent.

Environmental impact

The burning of coal and/or petroleum by industry and syngas the sulfur is extracted before the gas is burned.

Precautions

Carbon disulfide, carbon oxysulfide, hydrogen sulfide, and sulfur dioxide should all be handled with care.

Although sulfurous acid which in sufficient quantities may harm the lungs, eyes or other tissues. In organisms without lungs such as insects or plants, it otherwise prevents respiration.

Hydrogen sulfide is toxic. Although very pungent at first, it quickly deadens the sense of smell, so potential victims may be unaware of its presence until death or other symptoms occur.

See also

• Sulfur cycle
• Disulfide bond
• Sulfonium S⁺, S⁺R₃
• Ultra-low sulfur diesel
• Claus sulfur recovery process

References