There are actually two common forms of tin oxide:
* Tin(II) oxide (SnO), also known as stannous oxide.
* Tin(IV) oxide (SnO₂), also known as stannic oxide.
The difference between the two is the oxidation state of the tin atom. Sn(II) has a +2 oxidation state, while Sn(IV) has a +4 oxidation state.
