Sodium stannate
Sodium stannate, formally sodium hexahydroxostannate(IV), is the inorganic compound with the formula Na[Sn(OH)]. This colourless salt forms upon dissolving metallic tin or tin(IV) oxide in sodium hydroxide, and is used as a stabiliser for hydrogen peroxide. In older literature, stannates are sometimes represented as having the simple oxyanion SnO, in which case this compound is sometimes named as sodium stannate–3–water and represented as NaSnO·3HO, a hydrate with three waters of crystallisation. The anhydrous form of sodium stannate, NaSnO, is recognised as a distinct compound with its own CAS Registry Number, and a distinct material safety data sheet . Alkali metal stannate compounds are prepared by dissolving elemental tin in a suitable metal hydroxide, in the case of sodium stannate by the reaction: A similar reaction occurs when tin dioxide is dissolved in base: The anhydrous form can also be prepared from tin dioxide by roasting with sodium carbonate in a mixed carbon monoxide / carbon dioxide environment: The anion is a coordination complex that is octahedral in shape, similar to most stannates, such as the hexachlorostannate anion . The Sn—O bond distances average 2.071 Å.