Processes of Reductive Decomposition of APT above 400°C; Transformation of APT ® KTB ® ß-W in the Presence of Κ

Ammonium-tungsten-oxide bronzes (ATB) are formed in the course of thermal decomposition of ammonium paratungstate (APT).The formation of a hexagonal ATB between 400 and 600°C was known.It has now been found, by continuous measurement of the NH 3 evolved, and by X-ray analysis, that a tetragonal ATB can also be detected in a reductive decomposition, as well as the known HTB (hydrogen-TB).The subsequent appearance of the three oxide bronzes and a specific ATB-KTB transformation in the presence of potassium is shown.