V 5515 (OTTO) Vanadium(IV) oxide sulphate, hydrate ≥99.9% Cas 123334-20-3 - used as a catalyst for the oxidative aromatization of cyclohexenone. V 5515 (OTTO) Vanadium(IV) oxide sulphate, hydrate ≥99.9% Cas 123334-20-3 - used as a component in some food supplements.