Bisulphide :: Bisulphide (n.) A sulphide having two atoms of sulphur in the molecule; a disulphide, as in iron pyrites, FeS2; -- less frequently called bisulphuret..
Bisulphite :: Bisulphite (n.) A salt of sulphurous acid in which the base replaces but half the hydrogen of the acid; an acid sulphite.