Calciumwolframat

Bezeichnung:Calciumwolframat

CAS-Nr7790-75-2

Englisch Name:Calcium tungstate

CBNumberCB6135863

SummenformelCaO4W

Molgewicht287.92

MOL-Datei7790-75-2.mol

Synonyma

Calciumwolframat

Calciumwolframat physikalisch-chemischer Eigenschaften

Schmelzpunkt	1620°C
Dichte	6.06 g/mL at 25 °C (lit.)
storage temp.	-20°C
Löslichkeit	Insoluble in H{2}O. Decomposes by hot HCl, HNO{3}
Aggregatzustand	Powder
Wichte	6.062
Farbe	white
Wasserlöslichkeit	insoluble H2O; decomposed by hot HCl, HNO3 [MER06]
Merck	14,1712
Solubility Product Constant (Ksp)	pKsp: 8.06
Expositionsgrenzwerte	ACGIH: TWA 3 mg/m3 NIOSH: TWA 5 mg/m3; STEL 10 mg/m3
CAS Datenbank	7790-75-2(CAS DataBase Reference)
EPA chemische Informationen	Calcium tungsten oxide (CaWO4) (7790-75-2)

Sicherheit

WGK Germany	3
TSCA	Yes
HS Code	28418030

Gefahreninformationscode (GHS)

Calcium tungstate Chemische Eigenschaften,Einsatz,Produktion Methoden

Chemische Eigenschaften
-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]
Verwenden
Calcium tungstate can be ued for preparing screens for x-ray observations and photographs; in luminous paints; in scintillation counters.
Verwenden
Calcium tungsten oxide is used as a luminophore.
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.
Vorbereitung Methode
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.
Allgemeine Beschreibung
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
Not classified
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 I4_1/a, and there are four formula units per unit cell.

Calcium tungstate Upstream-Materialien And Downstream Produkte

Calciumwolframat Anbieter Lieferant Produzent Hersteller Vertrieb Händler.

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