Thermal expansion of In₂O₃

The thermal expansion of In₂O₃ powder was determined over the temperature range 30–968°C using X-ray techniques. The values of Δa/a_O, as determined by the least-squares method, are given by Δa/a_O = (7.20±0.06) x 10⁻⁶ T+ (1.15±0.08)±10⁻⁹ T². The values of the cell constant at various temperatures were determined by extrapolation techniques using the extrapolation function ½(cos²θ/sinθ + cos²θ/θ). The accurate value of the cell constant at room temperature is a_O = 10.1194±0.0005 Å, at 30°C. From the sharpness of the high-temperature photographs, it is concluded that no dissociation of In₂O₃ powders takes place on heating in vacuum up to 968°C.