In chemistry, a disulfide usually refers to the structural unit composed of a linked pair of sulfur atoms. The disulfide anion is S22−. The term disulfide can also refer to a chemical compound that contains a disulfide center, such as diphenyl disulfide, C6H5S-SC6H5. Sulfur is usually assigned to the reduced oxidation number −2, described as S2− and called sulfide. It has the electron configuration of a noble gas (argon). In disulfides, sulfur is only reduced to a state wit… (More on Disulfide)