The Texture and Heat Treatment of Hydrated Tin (IV) Oxides
Various preparations of hydrated tin (IV) oxides are reported. These are classed as α- or β- stannic acids according to their stability in concentrated hydrochloric acid. Precipitation in the cold gives α- stannic acid, whilst preparations at high temperature result in β- stannic acid; the former being of smaller particles than those of the latter.
The surface texture of these preparations have been characterised from their nitrogen adsorption isotherms. They have been subjected to thermogravimetric analysis (TG), differential thermal analysis (DTA) and X-ray diffraction. There is no formation of stoichiometric hydrates in the oxide system but water is adsorbed on the particles which can be identified as small crystallites of cassiterites (SnO2).
KeywordsAdsorption Isotherm Differential Thermal Analysis Ammonium Chloride Concentrate Hydrochloric Acid Nitrogen Adsorption Isotherm
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