Selenium
Organoselenium compounds

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 Se, analogues of thioethers), diselenides (R Se, analogues of disulfides), and selenols (RSeH, analogues of thiols). 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.
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