Sulfur or sulphur (British English; see spelling below) is a chemical element with symbol S and atomic number 16. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow crystalline solid when at room temperature. Chemically, sulfur can react as either an oxidant or reducing agent. It oxidizes most metals and several nonmetals, including carbon, which leads to its negative charge in most organosulfur compounds, but it reduces several strong oxidants, such as oxygen and fluorine.

Sulfur occurs naturally as the pure element (native sulfur) and as sulfide and sulfate minerals. Elemental sulfur crystals are commonly sought after by mineral collectors for their distinct, brightly colored polyhedron shapes. Being abundant in native form, sulfur was known in ancient times, mentioned for its uses in ancient Greece, China and Egypt. Fumes from burning sulfur were used as fumigants, and sulfur-containing medicinal mixtures were used as balms and antiparasitics. Sulfur is referenced in the Bible as brimstone (burn stone) in English, with this name still used in several nonscientific tomes. It was needed to make the best quality of black gunpowder. In 1777, Antoine Lavoisier helped convince the scientific community that sulfur was a basic element, rather than a compound.

Elemental sulfur was once extracted from salt domes where it sometimes occurs in nearly pure form, but this method has been obsolete since the late 20th century. Today, almost all elemental sulfur is produced as a byproduct of removing sulfur-containing contaminants from natural gas and petroleum. The element's commercial uses are primarily in fertilizers, because of the relatively high requirement of plants for it, and in the manufacture of sulfuric acid, a primary industrial chemical. Other well-known uses for the element are in matches, insecticides and fungicides. Many sulfur compounds are odoriferous, and the smell of odorized natural gas, skunk scent, grapefruit, and garlic is due to sulfur compounds. Hydrogen sulfide produced by living organisms imparts the characteristic odor to rotting eggs and other biological processes.

Sulfur is an essential element for all life, and is widely used in biochemical processes. In metabolic reactions, sulfur compounds serve as both fuels and respiratory (oxygen-alternative) materials for simple organisms. Sulfur in organic form is present in the vitamins biotin and thiamine, the latter being named for the Greek word for sulfur. Sulfur is an important part of many enzymes and in antioxidant molecules like glutathione and thioredoxin. Organically bonded sulfur is a component of all proteins, as the amino acids cysteine and methionine. Disulfide bonds are largely responsible for the mechanical strength and insolubility of the protein keratin, found in outer skin, hair, and feathers, and the element contributes to their pungent odor when burned.

Read more about Sulfur:  Production, Compounds, Precautions

Other articles related to "sulfur":

Liver Of Sulfur
... Liver of Sulfur is a poorly defined mixture of potassium sulfide, potassium polysulfide, potassium thiosulfate, and probably potassium bisulfide ... Synonyms include hepar sulfuris, sulfur, sulfurated potash and sulfurated potassa ... Liver of sulfur is mainly used in metalworking to form a patina, turning copper alloys brown or black ...
Stratospheric Sulfur Aerosols - Chemistry
... The chemistry of stratospheric sulfur aerosols varies significantly according to their source ... The chemical reactions affecting both the formation and elimination of sulfur aerosols are not fully understood ... to determine a viable approach for geoengineering uses of sulfur aerosol formation ...
Sulfur - Precautions
... Elemental sulfur is non-toxic, as generally are the soluble sulfate salts, such as Epsom salts ... When sulfur burns in air, it produces sulfur dioxide ... Sulfur trioxide (made by catalysis from sulfur dioxide) and sulfuric acid are similarly highly corrosive, due to the strong acids that form on contact with water ...
Staphylothermus - Metabolism
... Both organisms are sulfur dependent, extreme marine thermophiles ... These archeons require sulfur for growth but can produce hydrogen if sulfur becomes limited ... Staphylothermus marinus converts sulfur to hydrogen sulfide using these extremozymes ...
Lower Sulfur Oxides
... The lower sulfur oxides are a group of chemical compounds consisting of SO, sulfur monoxide and its dimer S2O2 S2O sulfur monoxides, SnO, based on cyclic Sn rings ... blue "sesquioxide", S2O3, formed by dissolving sulfur in liquid SO3 appears to be a mixture of polysulfate salts of the S42+ and S82+ ions ... Sulfur monoxide, monomer (SO) and dimer (S2O2) These are stable molecules that have been trapped at low temperature (see sulfur monoxide article) ...