Description
BaSiO3 is orthorhombic with unit-cell dimensions of
a = 5.6182(5)?, b = 12.445(1), c = 4.5816 ?. It is dimorphic
with α-BaSiO3 stable below about 990°C but forms
β-BaSiO3 above 1000°C. A 1:1 mol ratio of BaO–SiO2
fired at 850°C and 1050°C serves to form the two
dimorphs.
The enthalpy of solution of BaSiO3 in (3.15 mol/dm3
HF + 8.13 mol/dm
3 HCl) has been measured. From the
results, the standard molar enthalpy of formation of
BaSiO3 (s) was calculated. The value obtained was
-1606.4±2.6 kJ/mol.
Chemical Properties
Colorless powder. Insoluble in water; soluble in acids.
Uses
Barium silicate films that are suitable for use as transmission media in integrated optical circuits. It is shown that the films, which can be produced with a wide range of refractive indices by suitable selection of the ratio of the target constituents, exhibit low optical attenuation. Hence it is used for integrated optical circuits. It is used in ceramics.
Preparation
Bariumsilicate can be prepared by calcining the oxide
with silica, SiO2, at an elevated temperature:
BaO + SiO2 + hea?BaSiO3
