Tin(II) oxide, also known as stannous oxide, is a chemical compound. Its chemical formula is SnO. It has tin in an oxidation state of +2. It also has oxide ions in it.
It is normally a blue-black solid. It can be red but the red form is more unstable. It burns in air with a green flame to make tin(IV) oxide. It is a reducing agent. It is rarer than tin(IV) oxide. It dissolves in acids to make a colorless solution.
It can be made by reacting sulfuric acid with tin and reacting the tin(II) sulfate made with sodium hydroxide to make the tin(II) oxide hydrate. This is heated to get the tin(II) oxide.
It is used in touchscreens. It is used to make a glass with gold in it called ruby glass.