Tin(II) oxide is compound made of one atom of tin and one atom of oxygen, as represented by the chemical formula SnO. It appears as either a blue-black solid or a red solid, depending on the production method.
The Roman numeral II in tin(II) oxide represents the positive-two charge of the tin ion. It is balanced by a minus-two charge from the oxygen ion. In its red form, tin(II) oxide may be used in the manufacturing of red glass. It is also used for illuminating objects with ultraviolet light. Tin(II) oxide may also be called stannous oxide or tin monoxide. It can be produced by heating tin(II) oxide hydrate.