Molecular Formula | CaO4W |
Molar Mass | 287.92 |
Density | 6.06 g/mL at 25 °C (lit.) |
Melting Point | 1620°C |
Water Solubility | insoluble H2O; decomposed by hot HCl, HNO3 [MER06] |
Solubility | Insoluble in H{2}O. Decomposes by hot HCl, HNO{3} |
Appearance | Powder |
Specific Gravity | 6.062 |
Color | white |
Exposure Limit | ACGIH: TWA 3 mg/m3NIOSH: TWA 5 mg/m3; STEL 10 mg/m3 |
Solubility Product Constant(Ksp) | pKsp: 8.06 |
Merck | 14,1712 |
Storage Condition | -20°C |
MDL | MFCD00010913 |
Physical and Chemical Properties | Character white powder. melting point 1580 ℃ relative density 5.98g/cm3 solubility insoluble in water. |
Use | Used for fluorescent coating, photography, optical screen tube, medicine, X-ray photo and fluorescent lamp |
WGK Germany | 3 |
TSCA | Yes |
HS Code | 28418030 |
EPA chemical substance information | information provided by: ofmpeb.epa.gov (external link) |
solubility in water (g/100ml) | grams dissolved per 100ml of water: 2.387 × 10-3/20 ℃ |
toxicity | exposure to tungsten compounds can cause irritation and inflammation of the upper and deep Airways. Has a stimulating effect on the skin. Operators should wear anti-virus masks, dust suits, gloves and glasses. At all stages of the preparation and use of tungsten and its compounds, the leakage of dust is prevented. |
Use | used in fluorescent coatings, photographic light screen tubes, medicine, X-ray photo and fluorescent lamp, etc. mainly used in the production of ammonium paratungstate, tungsten trioxide, tungsten iron, alloy steel, hard alloy, tungsten material, tungsten wire and tungsten alloy and other tungsten products. Used as a raw material of Tungsten series chemical products. |
production method | calcium oxide or calcium hydroxide is reacted with tungsten oxide or tungsten hydroxide in an alkali metal hydroxide or carbonate solution to produce calcium tungstate. Sodium tungstate is mixed with sodium sulfide and dissolved in water, then an aqueous zinc chloride solution is added, filtered, and the filtrate is treated with pure calcium chloride to obtain calcium tungstate. |