Calcium Tungstate

Name:
Calcium Tungstate
Detailed information:
Note: Synthetic crystals are available for use as scintillation counters and possible application in lasers.

Chemistry name:	calcium orthotungstate; calcium wolframate normal
M Formula:	CaWO4
Properties:
White crystals. D 6.062. Soluble in ammonium chloride; insoluble in water; decomposed by hot acids.
Derivation:
(1) Interaction of calcium chloride and sodium tungstate. (2) Occurs in nature as scheelite, in Nevada, California, Arizona, Utah, Colorado, New Zealand, Europe.
Method of purification:
A slurry of powdered scheelite is treated with soda ash to form the soluble sodium tungstate. Insoluble impurities are filtered off, and calcium tungstate is precipitated with lime.
Use:
Luminous paints, fluorescent lamps, photography, medicine (radiopaque agent).