Tags: Chemical Compound, Chemical Substance.
Sodium selenite is a salt a colourless solid and the most common water-soluble selenium compound. It has the formulas Na2SeO3 and Na2SeO3(H2O)5 (CAS#26970-82-1). Respectively these are the anhydrous salt and its pentahydrate. This hydrated salt is the more common one. The hydrated and anhydrous salts behave identically for most purposes although their molar masses differ.
