Sodium stannite

Sodium stannate

Names
IUPAC name Sodium hexahydoxostannate(IV)
Other names disodium hexahydroxyltin Sodium stannate(IV) sodium stannate–3–water sodium tin(IV) oxide hydrate
Identifiers
CAS Number	12027-70-2
ECHA InfoCard	100.031.554
Properties
Chemical formula	H6Na2O6Sn
Molar mass	266.73 g/mol
Appearance	Colorless or white solid
Density	4.68 g/cm3
Boiling point	N/A
Hazards
Safety data sheet	[1]
GHS hazard statements	H300 + H310 + H330 + H410
NFPA 704	0 2 0
Flash point	57 °C (135 °F; 330 K)
Autoignition temperature	N/A
Lethal dose or concentration (LD, LC):
LD50 (median dose)	2132 mg/kg [Mouse]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Sodium stannate, formally sodium hexahydoxostannate(IV), is the inorganic compound with the formula Na₂[Sn(OH)₆]. 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 SnO₃²⁻, in which case this compound is sometimes named as sodium stannate–3–water and represented as Na₂SnO₃·3H₂O, a hydrate with three waters of crystallisation. The anhydrous form of sodium stannate, Na₂SnO₃, is recognised as a distinct compound with its own CAS Registry Number,12058-66-1 , and a distinct materials 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 [SnCl₆]²⁻. The Sn—O bond distances average 2.071 Å.