The correct name of the compound CoSO3 is cobalt(II) sulfite.
In this compound, "Co" represents the metal cobalt, which is in its +2 oxidation state. The polyatomic ion "SO3" is sulfite. The naming follows the rules of coordination chemistry, where the metal is named first, followed by the ligands. In this case, cobalt is coordinated to the sulfite ion.
So, the compound CoSO3 is correctly named as cobalt(II) sulfite, adhering to the IUPAC nomenclature for coordination compounds. This systematic naming convention ensures clarity and consistency in communicating the composition and structure of chemical compounds.