<P> In 1892, Rudolf Von Wagner distinguished soda, potash, double (soda and potash), and fixing (i.e., stabilizing) as types of water glass . The fixing type was "a mixture of silica well saturated with potash water glass and a sodium silicate" used to stabilize inorganic water color pigments on cement work for outdoor signs and murals . </P> <P> Sodium silicates are colorless glassy or crystalline solids, or white powders . Except for the most silicon - rich ones, they are readily soluble in water, producing alkaline solutions . </P> <P> Sodium silicates are stable in neutral and alkaline solutions . In acidic solutions, the silicate ions react with hydrogen ions to form silicic acids, which tend to decompose into hydrated silicon dioxide gel . Heated to drive off the water, the result is a hard translucent substance called silica gel, widely used as a desiccant . </P> <P> Solutions of sodium silicates can be produced by treating a mixture of silica (usually as quartz sand), caustic soda, and water, with hot steam in a reactor . The overall reaction is </P>

What is the chemical formula of water glass