Compounds formed by reaction between hydroxylamine and an aldehyde
RCOH + H2NOH → RCH:NOH + H2O
If R is an aliphatic group, the aldoxime is generally a liquid or low melting solid. If R is aromatic, the aldoxime is a crystalline solid. Aldoximes have a planar structure and can exist in two isomeric forms. In the syn-form, the OH group is on the same side of the double bond as the H. In the anti form the OH and H are on opposite sides. Typically, aliphatic aldehydes give anti aldoximes; aromatic aldehydes give syn aldoximes.
