Hydrothermal chemistry of silicates. Part XVIII. Reactions in the system CaO–B2O3–SiO2–H2O

Abstract

An investigation of the system CaO–B₂O₃–SiO₂–H₂O at 250 and 415 °C has shown the ready formation of cristobalite, quartz, five identified silicates, six identified borates, and the borosilicates danburite and datolite. In addition ten unidentified and possibly new borates and a number of phases which could not be classified chemically and which may include silicates and borosilicates, were also prepared. Co-crystallisation of mixtures was as typical of this calcic system as it was of the analogous baric one. The unclassified compounds were characterised by their X-ray powder patterns and where possible in other ways. No borosilicate zeolites have so far been identified.