| Identification | More | [Name]
Calcium tungstate | [CAS]
7790-75-2 | [Synonyms]
ACID CALCIUM PHOSPHATE, MONOHYDRATE
CALCIUM ACID PHOSPHATE MONOHYDRATE
CALCIUM BIPHOSPHATE
CALCIUM BIPHOSPHATE, MONOHYDRATE
CALCIUM BIS(DIHYDROGENPHOSPHATE) MONOHYDRATE
Calcium dihydrogenphoshate
CALCIUM DIHYDROGEN PHOSPHATE
CALCIUM DIHYDROGENPHOSPHATE MONOHYDRATE
CALCIUM PHOSPHATE, MONOBASIC
CALCIUM PHOSPHATE MONOBASIC MONOHYDRATE
CALCIUM PHOSPHATE MONOHYDRATE, MONOBASIC
CALCIUM TETRAHYDROGEN DIPHOSPHATE MONHYDRATE
CALCIUM TETRAHYDROGEN DIPHOSPHATE MONOHYDRATE
calcium tetraoxotungstate
CALCIUM TUNGSTATE
CALCIUM TUNGSTATE(VI)
CALCIUM TUNGSTEN OXIDE
calcium wolframate
MONOCALCIUM PHOSPHATE
PRIM-CALCIUM PHOSPHATE MONOHYDRATE | [EINECS(EC#)]
232-219-4 | [Molecular Formula]
CaO4W | [MDL Number]
MFCD00149602 | [Molecular Weight]
287.92 | [MOL File]
7790-75-2.mol |
| Chemical Properties | Back Directory | [Melting point ]
1620°C | [density ]
6.06 g/mL at 25 °C(lit.)
| [storage temp. ]
-20°C | [solubility ]
Insoluble in H{2}O. Decomposes by hot HCl, HNO{3} | [form ]
powder
| [color ]
white | [Specific Gravity]
6.062 | [Water Solubility ]
insoluble H2O; decomposed by hot HCl, HNO3 [MER06] | [Merck ]
14,1712 | [Solubility Product Constant (Ksp)]
pKsp: 8.06 | [Exposure limits]
ACGIH: TWA 3 mg/m3
NIOSH: TWA 5 mg/m3; STEL 10 mg/m3 | [CAS DataBase Reference]
7790-75-2(CAS DataBase Reference) | [EPA Substance Registry System]
7790-75-2(EPA Substance) |
| Hazard Information | Back Directory | [Chemical Properties]
-325 mesh, 10μm or less 99.9% pure; occurs in nature as mineral scheelite; white tetr powder(s), a=0.524 nm, c=1.138 nm; can be prepared by heating tungstic acid and CaO or CaCO3; used in tumor treatment and in luminous paint [KIR83] [STR93] [MER06] | [Uses]
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. | [Application]
Calcium tungstate is well known as the phosphor that emits light in λ: 310–700 nm under the excitation light in λ: 220–300 nm. The peak wavelength is positioned at 440 nm, causing it to give off a blue color. | [Production Methods]
A single crystal is grown from melt by the Czochralski method. Rare earth ions are easy to incorporate into the crystal during growth. Fluorescent films are deposited on a glass substrate through vacuum evaporation using a W filament heated at 2000℃ for about 3 min, followed by thermal annealing in oxygen at 550℃ for 2 h. The film becomes crystalline through this thermal annealing.
| [General Description]
Calcium tungstate (CaWO4) is an optical material, which can be used as a laser host material for a variety of electronic applications. It has a scheelite structure with luminescence, and thermo-luminescence properties. | [Flammability and Explosibility]
Notclassified | [Structure and conformation]
The space lattice of CaWO4 belongs to the tetragonal system, and its Scheelite structure has lattice constants of a=0.524 nm and c=1.138 nm. The space group is I41/a, and there are four formula units per unit cell. |
| Raw materials And Preparation Products | Back Directory | [Raw materials]
Calcium hydroxide-->Calcium oxide-->Sodium tungstate dihydrate-->Alkali Metals, plasma standard solution, Specpure, Ba,Be,Ca,Cs,K,Li,Mg,Na,Rb,Sr, 100μg/ml-->Tungsten trioxide |
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