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8157632 
Journal Article 
REDUCTION OF WO3 BY PHOSPHORUS 
Mathis, H; Glaum, R; Gruehn, R 
1991 
Yes 
Acta Chemica Scandinavica
ISSN: 0904-213X
EISSN: 1902-3103 
MUNKSGAARD INT PUBL LTD 
COPENHAGEN 
45 
8 
781-784 
English 
WOS:A1991GF05700003 
The reduction of WO3 by elemental phosphorus at 800°C leads to the formation of several products. Depending on the molar ratio n(P):n(WO3) in the course of this investigation, WP, WP2, WPO5 and, for the first time, tungstcn(IV) diphosphate, WP2O7, were prepared. By chemical vapour transport reactions (transport agent iodine; 200 mg per ampoule; 1050 950 °C), the phosphides and phosphates of tungsten can be purified and crystallized. Heterogeneous and homogeneous equilibria, responsible for the vapour-phase transport of the tungsten compounds, will be discussed.