A seleninic acid is an organoselenium compound and an oxoacid with the general formula RSeO2H, where R ≠ H. Its structure is R−Se(=O)−OH. It is a member of the family of organoselenium oxoacids, which also includes selenenic acids and selenonic acids, which are R−Se−OH and R−Se(=O)2−OH, respectively. The parent member of this family of compounds is methaneseleninic acid (CH3−Se(=O)−OH), also known as methylseleninic acid or "MSA".
Seleninic acids (particularly areneseleninic acids) are useful catalysts for hydrogen peroxide epoxidations, Baeyer–Villiger oxidations, oxidations of thioethers, etc.; peroxyseleninic acids (R−Se(=O)−OOH) are thought to be the active oxidants.[1][2][3]
Methaneseleninic acid has been characterized by X-ray crystallography.[4] The configuration about the selenium atom is pyramidal, with Se-C = 1.925(8) Å, Se-O = 1.672(7) Å, Se-OH = 1.756(7) Å, the angle OSeO = 103.0(3)°, the angle HO-Se-C = 93.5(3)°, and the angle OSeC = 101.4(3)°. The structure is isomorphous to that of methanesulfinic acid [5]
Benzeneseleninic acid (C6H5−Se(=O)−OH) had been previously characterized by X-ray methods[6] and its optical resolution reported.[7]