Tungstic Oxide

Name:
Tungstic Oxide
Detailed information:

Chemistry name:	tungstic acid anhydride; tungstic anhydride; tungsten trioxide; wolframic acid, anhydrous
M Formula:	WO3
Properties:
Canary-yellow, heavy powder, dark-orange when heated and regains original color on cooling. Mp 1473C, d 7.16. Insoluble in water, soluble in caustic alkalies, soluble with difficulty in acids. Noncombustible.
Derivation:
Scheelite ore is treated with hydrochloric acid and the resulting product dissolved out with ammonia. The complex ammonium tungstate can then be ignited to tungstic oxide.
Hazard:
Toxic material. TLV: 5 mg(W)/m3.
Use:
To form metal by reduction, alloys, preparation of tungstates for X-ray screens, fireproofing fabrics, yellow pigment in ceramics.