Silicates

Silicates are compounds which may be regarded as derived from silicic acids by replacement of the hydrogen by metals. Owing to the complicated nature of most of the silicates, however, they are more usually written as compounds of silica and other oxides, the real nature of the compound being unknown. They are almost all insoluble, the alkaline silicates being the only exceptions. Sodium silicate (NaSiO₃) is known as soluble glass, and its solution is employed for rendering wood, etc., fireproof. Many rocks consists almost entirely of silicates, as do most of the minerals which form the earth's crust. Glass also consists entirely of silicates; thus flint-glass consists of alkaline and lead silicates, other glass of silicates of calcium, sodium, potassium, etc, [GLASS, SILICA.]