Vanadium(III) sulfate
# Vanadium(III) sulfate

Vanadium(III) sulfate is the inorganic compound with the formula $V_2(SO_4)_3.$ It is a pale yellow solid that is stable to air, in contrast to most vanadium(III) compounds. It slowly dissolves in water to give the green aquo complex $[V(H_2O)_6]^{3+}.$

The compound is prepared by treating $V_2O_5$ in sulfuric acid with elemental sulfur:

    $V_2O_5$ + S + 3 $H_2SO_4$ → $V_2(SO_4)_3$ + $SO_2$ + 3 $H_2O$

This transformation is a rare example of a reduction by elemental sulfur.

When heated in vacuum at or slightly below 410 °C, it decomposes into vanadyl sulfate $(VOSO_4)$ and $SO_2.$ Vanadium(III) sulfate is stable in dry air but upon exposure to moist air for several weeks forms a green hydrate form.

Vanadium(III) sulfate is a reducing agent.

