Disulfide 65948 205345876 2008-04-13T15:54:26Z SilvonenBot 6351353 robot Adding: [[it:Disolfuro]] In [[chemistry]], a '''disulfide''' usually refers to the structural unit composed of a linked pair of sulfur atoms. The disulfide [[anion]] is S<sub>2</sub><sup>2−</sup>. The term '''disulfide''' can also refer to a [[chemical compound]] that contains a [[disulfide bond|disulfide center]], such as [[diphenyl disulfide]], C<sub>6</sub>H<sub>5</sub>S-SC<sub>6</sub>H<sub>5</sub>. Sulfur is usually assigned to the [[reduction (chemistry)|reduced]] [[oxidation number]] −2, described as S<sup>2−</sup> and called [[sulfide]]. It has the electron configuration of a [[noble gas]] ([[argon]]). In disulfides, sulfur is only reduced to a state with oxidation number −1. Its configuration then resembles that of [[chlorine]] and, like it, has the tendency to form a covalent bond with another S<sup>−</sup> ion to form a disulfide (S<sub>2</sub>)<sup>2−</sup> group. [[Oxygen]] can also do this; e.g. in [[peroxide]]s such as H<sub>2</sub>O<sub>2</sub>. In many cases, each of the two sulfur atoms in a disulfide group is covalently bonded to a carbon atom in an [[organic compound]], forming a [[disulfide bond]], sometimes called a ''disulfide linkage'' or a ''disulfide bridge''. The tendency is a bit more elaborate in the case of sulfur, which can form [[polysulfide]]s. ==Some examples== *[[Iron]] disulfide (FeS<sub>2</sub>), known as the [[mineral]] [[pyrite]]. *[[Disulfur dichloride]] (S<sub>2</sub>Cl<sub>2</sub>), a distillable liquid. *The amino acid [[cystine]] *The [[vitamin]] [[lipoic acid]] *[[Diphenyl disulfide]] (Ph<sub>2</sub>S<sub>2</sub>). <center> {|align="center" class="wikitable" |<center>[[Image:Pyrite-unit-cell-3D-balls.png|100px]]</center>||<center>[[Image:Disulfur-dichloride-3D-balls.png|100px]]</center>||<center>[[Image:Cystine-3D-balls.png|100px]]</center>||<center>[[Image:Lipoic-acid-3D-balls.png|150px]]</center>||<center>[[Image:Diphenyl-disulfide-3D-balls.png|150px]]</center> |- |<center>FeS<sub>2</sub> [[unit cell]]</center>||<center>S<sub>2</sub>Cl<sub>2</sub></center>||<center>cystine</center>||<center>lipoic acid</center>||<center>Ph<sub>2</sub>S<sub>2</sub></center> |} </center> ==Misnomers== Disulfide is also used to refer to compounds that contain two sulfide (S<sup>2−</sup>) centers. The compound [[carbon disulfide]], CS<sub>2</sub> is described with the structural formula i.e. S=C=S. This molecule is not a disulfide in the sense that it lacks a S-S bond. Similarly, [[molybdenum disulfide]], MoS<sub>2</sub>, is not a disulfide in the sense again that its sulfur atoms are not linked. <center> {|align="center" class="wikitable" |<center>[[Image:Carbon-disulfide-3D-balls.png|200px]]</center>||<center>[[Image:Molybdenite-3D-balls.png|200px]]</center> |- |<center>CS<sub>2</sub></center>||<center>MoS<sub>2</sub></center> |} </center> ==See also== * [[Disulfide bond]] * [[Diphenyl disulfide]] ==References== [[Category:Anions]] [[de:Disulfide]] [[it:Disolfuro]] [[ja:ジスルフィド]] [[fi:Disulfidi]]