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Properties - Sodium Silicate
December 19, 2001
The term sodium silicate refers to any one of several compounds containing sodium oxide, Na2O, and silica, Si2O, or a mixture of sodium silicates. Sodium orthosilicate is Na4SiO4 (or 2Na2O·SiO2); sodium metasilicate is Na2SiO3 (or Na2O·SiO2); sodium disilicate is Na2Si2O5 (or Na2O·2SiO2); sodium tetrasilicate is Na2Si4O9 (or Na2O·4SiO2). All these compounds are transparent, glassy or crystalline solids that have high melting points (above 800°C) and are water soluble. They are produced chiefly by fusing sand and sodium carbonate in various proportions. The product is commonly known as water glass. The greatest single use of sodium silicates is as a raw material for making silica gel.
Synonyms: water glass, soluble glass, silicate of soda, sodium orthosilicate,
sodium silicate glass
Molecular formula: Na4O4Si
CAS No: 2344-09-8
EC No: 239-981-7
Appearance: colourless liquid
Boiling point: ca 102°C for a 40% aqueous solution
Specific gravity: 1.3 for a ca. 40% solution
Stable. Incompatible with acids, most metals, many organic materials.
Harmful by ingestion. Corrosive - may cause burns through skin or eye contact. Very destructive of mucous membranes.
Non-hazardous for air, sea and road freight.
Safety glasses, gloves.