Well-defined colloidal tin(IV) oxide particles

Spherical and rod-like SnO₂ particles of narrow size distribution have been obtained by aging at 100°C acidified tin(IV) chloride solutions in the presence of urea or formamide. It was shown that spherical particles, the x-ray diffraction of which was characteristic of cassiterite, consisted of a large number of much smaller subunits. The rod-like particles had the same structure, but of higher degree of crystallinity. Infrared spectra of these powders were evaluated in terms of the theory of the average dielectric constant (TADC), in order to gain additional information on the particle morphology and the state of aggregation.