| Abstract: | Investigation on the System SrO? SiO2? H2O On addition sodium silicate solutions to solutions of Sr(OH)2, at room temperature strontium hydrogensilicates are precipitated which are always amorphous and contain silicate anions of various condensation degrees. At about 100°C at first also amorphous products are formed containing lower- and higher-molecular silicate anions. On standing of these precipitates at about 80°C under the mother liquor, however, cristallization occurs under complete degradation of the higher-molecular anions to monomeric resp. dimeric silicate anions. In dependence on the Na2O: SiO2 ratio of the sodium silicate solutions and on the Sr(OH)2 concentrations the following crystalline compounds are formed: 1.25 SrO · 1 SiO2 · 2 H2O, 3 SrO · 2 SiO2 · 3 H2O and 3 SrO · 2 SiO2 · 4 H2O, with monomeric silicate anions; 2 SrO · 2 SiO2 · 1.5 H2O; 2 SrO · 2 SiO2 · 2 H2O, and 2 SrO · 2 SiO2 · 3 H2O, with dimeric anions. |
