FORMATION OF NA0.9MO6O17 IN A SOLID-PHASE PROCESS - TRANSFORMATIONS OF A HYDRATED SODIUM MOLYBDENUM BRONZE, NA0.23(H2O)0.78MOO3, WITH HEAT-TREATMENTS IN A NITROGEN ATMOSPHERE

The transformations of hydrated sodium molybdenum bronze, Na0.23(H2O)0.78MoO3, with heat treatments in a nitrogen atmosphere are as follows: Na0.23(H2O)0.78MoO3 (AD) at 330 K Na0.23(H2O)0.5MoO3 (VD) at 457 K Na0.23MoO3 (with VD structure) at 583 k Na0.9Mo6O17 + a small amount of other materials at 800 and 900 K melt. This indicates a new and variable formation process of alkali metal molybdenum bronzes. In this process, Na0.9Mo6O17 was formed in the solid phase without the formation of any intermediate products. Its formation temperature was about 600 K, which was less than those of the usual preparation methods by about 200 K.