Study of the polymerisation of some antimonates by the dry process and the aqueous process

This work is an attempt to classify the different antimonic acid and alkaline antimonate species. A number of these were already known and their structures studied, but the temperature regions in which they could exist were generally unknown and certain characteristic properties needed to be defined. Other species, already described by some authors, were actually mixtures; it was possible to prepare them in the pure state by changing the conditions of preparation (as in the case of pyrochlore NaSbO3 and cubic KSbO3, 0.7 H2O). Finally, others had been prepared but their structure was still undefined (as with Sb2O5, 1/2 H2O) or they were not known to be crystallised (KSbO3, 2.2 H2O). New species such as amorphous sodium and silver antimonates and amorphous antimonic acid were also isolated. In addition, the study of the behavior of these antimonates in acid solution showed that whatever the nature of the antimonate, it is converted, partially of completely into a pyrochlore species of which the proportion can be predicted as a function of the acidity of the medium, and the composition as a function of the nature of the cation. (author)