Strontium Silicate occurs naturally associated with barium and calcium as the silicoaluminate brewsterite, H4[Ba,Sr,Ca]Al2Si6O18.3H2O. A metasilicate, in colourless, transparent, fibrous crystals, of density 3.652, has been formed by fusing a mixture of silica with strontium chloride and strontium carbonate. By rapid cooling, a practically isotropic glass of density 3.540 is obtained, but this can be transformed into the microcrystalline variety by careful heating. The heat of formation of strontium metasilicate from strontium oxide and silica is 21.3 Cal. Its melting-point is 1580°±4° C. There is also an ortho-silicate melting above 1750° C.
By the action of sodium metasilicate on a strontium salt a hydrated metasilicate, SrSiO3.H2O, is formed. Strontium hydroxide solution reacts with silicic acid or powdered quartz to produce a number of acid salts. |