Sodium Selenite. Disodium Selenite . Monosodium Selenite . Selenous Acid Disodium Salt . Selenous Acid, Disodium Salt . Sodium Biselenite . Sodium Selenite Pentahydrate . Biselenite, Sodium . Pentahydrate, Sodium Selenite . Selenite Pentahydrate, Sodium . Selenite, Disodium . Selenite, Monosodium . Selenite, Sodium . The disodium salt of selenious acid. It is used therapeutically to supply the trace element selenium and is prepared by the reaction of SELENIUM DIOXIDE with SODIUM HYDROXIDE. . 0.58