Translations:Vitamin D/10/en

Chemically, the various forms of vitamin D are secosteroids, that is, steroids in which one of the bonds in the steroid rings is broken. The structural difference between vitamin D₂ and vitamin D₃ is in the side chain, which contains a double bond, between carbons 22 and 23, and a methyl group on carbon 24 in vitamin D₂. Many vitamin D analogues have been synthesized.