Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula S8. Elemental sulfur is a bright yellow, crystalline solid at room temperature.
In biochemistry, a disulfide refers to a functional group with the structure R−S−S−R′. The linkage is also called an SS-bond or sometimes a disulfide bridge and is usually derived by the coupling of two thiol groups. In biology, disulfide bridges formed between thiol groups in two cysteine residues are an important component of the secondary and tertiary structure of proteins. Persulfide usually refers to R−S−S−H compounds.
In organic chemistry, a thiol, or thiol derivative, is any organosulfur compound of the form R−SH, where R represents an alkyl or other organic substituent. The −SH functional group itself is referred to as either a thiol group or a sulfhydryl group, or a sulfanyl group. Thiols are the sulfur analogue of alcohols, and the word is a blend of "thio-" with "alcohol".
In organic chemistry, an organic sulfide or thioether is an organosulfur functional group with the connectivity R−S−R' as shown on right. Like many other sulfur-containing compounds, volatile sulfides have foul odors. A sulfide is similar to an ether except that it contains a sulfur atom in place of the oxygen. The grouping of oxygen and sulfur in the periodic table suggests that the chemical properties of ethers and sulfides are somewhat similar, though the extent to which this is true in practice varies depending on the application.
Sulfide (British English also sulphide) is an inorganic anion of sulfur with the chemical formula S2− or a compound containing one or more S2− ions. Solutions of sulfide salts are corrosive. Sulfide also refers to chemical compounds large families of inorganic and organic compounds, e.g. lead sulfide and dimethyl sulfide. Hydrogen sulfide (H2S) and bisulfide (SH−) are the conjugate acids of sulfide.
Sodium thiosulfate (sodium thiosulphate) is an inorganic compound with the formula Na2S2O3.xH2O. Typically it is available as the white or colorless pentahydrate, Na2S2O3·5H2O. The solid is an efflorescent (loses water readily) crystalline substance that dissolves well in water.
Polysulfides are a class of chemical compounds containing chains of sulfur atoms. There are two main classes of polysulfides: inorganic and organic. Among the inorganic polysulfides, there are ones which contain anions, which have the general formula S2−
n. These anions are the conjugate bases of the hydrogen polysulfides H2Sn. Organic polysulfides generally have the formulae R1SnR2, where R = alkyl or aryl.
In chemistry, disproportionation, sometimes called dismutation, is a redox reaction in which one compound of intermediate oxidation state converts to two compounds, one of higher and one of lower oxidation states. More generally, the term can be applied to any desymmetrizing reaction of the following type, regardless of whether it is a redox or some other type of process:
Organosulfur compounds are organic compounds that contain sulfur. They are often associated with foul odors, but many of the sweetest compounds known are organosulfur derivatives, e.g., saccharin. Nature abounds with organosulfur compounds—sulfur is vasile 6ial for life. Of the 20 common amino acids, two are organosulfur compounds, and the antibiotics penicillin and sulfa drugs both contain sulfur. While sulfur-containing antibiotics save many lives, sulfur mustard is a deadly chemical warfare agent. Fossil fuels, coal, petroleum, and natural gas, which are derived from ancient organisms, necessarily contain organosulfur compounds, the removal of which is a major focus of oil refineries.
In organic chemistry, a sulfoxide, also called a sulphoxide, is an organosulfur compound containing a sulfinyl functional group attached to two carbon atoms. It is a polar functional group. Sulfoxides are oxidized derivatives of sulfides. Examples of important sulfoxides are alliin, a precursor to the compound that gives freshly crushed garlic its aroma, and dimethyl sulfoxide (DMSO), a common solvent.
Tetrasulfur tetranitride is an inorganic compound with the formula S4N4. This gold-poppy coloured solid is the most important binary sulfur nitride, which are compounds that contain only the elements sulfur and nitrogen. It is a precursor to many S-N compounds and has attracted wide interest for its unusual structure and bonding.
Sodium sulfide is the chemical compound with the formula Na2S, or more commonly its hydrate Na2S·9H2O. Both the anhydrous and the hydrated salts are colorless solids. They are water-soluble, giving strongly alkaline solutions. When exposed to moist air, Na2S and its hydrates emit hydrogen sulfide, an extremely toxic, flammable and corrosive gas which smells like rotten eggs.
Phosphorus sulfides comprise a family of inorganic compounds containing only phosphorus and sulfur. These compounds have the formula P4Sx with x ≤ 10. Two are of commercial significance, phosphorus pentasulfide (P4S10), which is made on a kiloton scale for the production of other organosulfur compounds, and phosphorus sesquisulfide (P4S3), used in the production of "strike anywhere matches".
Sodium hydrosulfide is the chemical compound with the formula NaSH. This compound is the product of the half-neutralization of hydrogen sulfide with sodium hydroxide (NaOH). NaSH and sodium sulfide are used industrially, often for similar purposes. Solid NaSH is colorless. The solid has an odor of H2S owing to hydrolysis by atmospheric moisture. In contrast with sodium sulfide, which is insoluble in organic solvents, NaSH, being a 1:1 electrolyte, is more soluble.
Sulfur tetrafluoride is the chemical compound with the formula SF4. It is a colorless corrosive gas that releases dangerous HF upon exposure to water or moisture. Despite these unwelcome characteristics, this compound is a useful reagent for the preparation of organofluorine compounds, some of which are important in the pharmaceutical and specialty chemical industries.
Selenium hexasulfide is a chemical compound with formula Se2S6. Its molecular structure consists of a ring of two selenium and six sulfur atoms, analogous to the S8 allotrope of sulfur (cyclooctasulfur) and other selenium sulfides with formula SenS8−n.
Copper(I) bromide is the chemical compound with the formula CuBr. This diamagnetic solid adopts a polymeric structure akin to that for zinc sulfide. The compound is widely used in the synthesis of organic compounds and as a lasing medium in copper bromide lasers.
A polysulfane is a chemical compound of formula H2Sn, where n > 1. Polysulfanes consist of unbranched chains of sulfur atoms terminated with hydrogen atoms. Compounds containing 2 – 8 concatenated sulfur atoms have been isolated, longer chain compounds have been detected, but only in solution. H2S2 is colourless, higher members are yellow with the colour increasing with the sulfur content. Even a trace of alkali will cause chemical decomposition, and containers need to be treated with acid to remove any traces of alkali. In the chemical literature the term polysulfanes is sometimes used for compounds containing −(S)n−, e.g. organic polysulfanes R1−(S)n−R2.
1,3,5-Trithiane is the chemical compound with the formula (CH2S)3. This heterocycle is the cyclic trimer of the otherwise unstable species thioformaldehyde. It consists of a six-membered ring with alternating methylene bridges and thioether groups. It is prepared by treatment of formaldehyde with hydrogen sulfide.
Ethane-1,1-dithiol is an organosulfur compound with formula CH3CH(SH)2. It is a colourless smelly liquid that is added to or found in some foods. The compound is an example of a geminal dithiol.
