Nomenclature
CAS number: 7790-75-2
CaO
4W; mol wt 287.92.
Ca 13.92%, O 22.23%, W 63.85%.
CaWO
4.
Description and references
Occurs in nature as the mineral scheelite. The article of commerce is usually made by pptn: Boericke,
Boericke, US 2390687 (1945); prepn
by heating a stoichiometric mixture of CaO or CaCO3 and
tungstic acid: Kroger, Nature 159, 674 (1947); prepn of single crystals: Uitert, Soden, J. Appl. Phys. 31, 328 (1960).
Properties
Tetragonal crystals. d 6.06. Practically insol in water. Dec by
hot HCl or HNO3.Use
Very small crystals have been used for injection
into malignant tumors, etc., thus affording by transillumination a
means of x-ray treatment; for preparing screens for x-ray observations
and photographs; in luminous paints; in scintillation counters.