Tin(II) oxide

Blue-black SnO can be produced by heating the tin(II) oxide hydrate, (x Metastable, red SnO can be prepared by gentle heating of the precipitate produced by the action of aqueous ammonia on a tin(II) salt. :SnC2O4·2H2O → SnO + CO2 + CO + 2 H2O Tin(II) oxide burns in air with a dim green flame to form SnO2. SnO is a reducing agent and is thought to reduce copper(I) to metallic clusters in the manufacture of so-called "copper ruby glass". ==Structure==

Black, α-SnO adopts the tetragonal PbO layer structure containing four coordinate square pyramidal tin atoms. This form is found in nature as the rare mineral romarchite. The asymmetry is usually simply ascribed to a sterically active lone pair; however, electron density calculations show that the asymmetry is caused by an antibonding interaction of the Sn(5s) and the O(2p) orbitals. The electronic structure and chemistry of the lone pair determines most of the properties of the material. Non-stoichiometry has been observed in SnO. The electronic band gap has been measured between 2.5eV and 3eV. ==Uses==

The dominant use of stannous oxide is as a precursor in manufacturing of other, typically divalent, tin compounds or salts. Stannous oxide may also be employed as a reducing agent and in the creation of ruby glass. It has a minor use as an esterification catalyst. Cerium(III) oxide in ceramic form, together with Tin(II) oxide (SnO) is used for illumination with UV light. Stannous oxide is also used in electroplating as a source of Sn2+ ions in solid state reactions to produce complex oxides, or in reactions with weak acids to manufacture stannous compounds. ==References==