Editing Selenium (section)

===Organoselenium compounds===
{{Main|Organoselenium chemistry}}
Selenium, especially in the II oxidation state, forms a variety of organic derivatives. They are structurally analogous to the corresponding [[organosulfur compounds]]. Especially common are selenides (R<sub>2</sub>Se, analogues of [[thioether]]s), diselenides (R<sub>2</sub>Se<sub>2</sub>, analogues of [[disulfide]]s), and [[selenol]]s (RSeH, analogues of [[thiol]]s). Representatives of selenides, diselenides, and selenols include respectively [[selenomethionine]], [[diphenyldiselenide]], and [[benzeneselenol]]. The [[sulfoxide]] in sulfur chemistry is represented in selenium chemistry by the selenoxides (formula RSe(O)R), which are intermediates in organic synthesis, as illustrated by the [[selenoxide elimination]] reaction. Consistent with trends indicated by the [[double bond rule]], selenoketones, R(C=Se)R, and selenaldehydes, R(C=Se)H, are rarely observed.<ref>{{cite journal |last1=Erker |first1=G. |last2=Hock |last3=Krüger |last4=Werner |last5=Klärner |last6=Artschwager-Perl |title=Synthesis and Cycloadditions of Monomeric Selenobenzophenone |journal=Angewandte Chemie International Edition in English |volume=29 |issue=9 |pages=1067–1068 |year=1990 |doi=10.1002/anie.199010671 |first2=R. |first3=C. |first4=S. |first5=F.G. |first6=U.}}</ref>