Вольфрамат натрия (VI)
Вольфрамат натрия (VI) атрибут
| Температура плавления: |
3410 °C(lit.) |
| Температура кипения: |
5660 °C(lit.) |
| плотность: |
2.3 g/mL at 25 °C(lit.) |
| давление пара: |
0Pa at 25℃ |
| растворимость: |
H2O: растворим |
| форма: |
проволока |
| пка: |
3.5[at 20 ℃] |
| цвет: |
white rhombohedral crystals, crystalline |
| Растворимость в воде: |
г/100 г H2O: 71,5 (0°C), 73,0 (20°C), 97,2 (100°C) [LAN05] |
| Мерк: |
13,8772 |
| LogP: |
0 |
| Справочник по базе данных CAS: |
13472-45-2(CAS DataBase Reference) |
| Рейтинг продуктов питания EWG: |
1 |
| FDA UNII: |
64LRH4405G |
| Система регистрации веществ EPA: |
Sodium tungsten oxide (Na2WO4) (13472-45-2) |
Вольфрамат натрия (VI) химические свойства, назначение, производство
Химические свойства
Sodium tungstate is a sodium salt of orthotungstate. It is a colorless crystals or white crystalline powder. Soluble in water; insoluble in alcohol and acids. noncombustible. Sodium tungstate has three crystalline forms, δ, γ and β. The transition temperature from δ to γ is about 570℃, and from γ to β is about 585℃. In hydrogen is heated to 700 ℃ also does not change, to 1100 ℃ will become metal tungsten.
Использование
Intermediate in preparation of tungsten compounds, (e.g., phosphotungstate), reagent, fire-proofing fabrics and cellulose, alkaloid precipitant.
Определение
ChEBI: Sodium tungstate is an inorganic sodium salt having tungstate as the counterion. Combines with hydrogen peroxide for the oxidation of secondary amines to nitrones. It has a role as a reagent. It contains a tungstate.
Подготовка
Sodium tungstate is obtained by digestion of tungsten ores, the economically important representatives of which are tungstates, in base. Illustrative is the extraction of sodium tungstate from wolframite:
Fe/MnWO4 + 2 NaOH + 2 H2O → Na2WO4?2H2O + Fe/Mn(OH)2
Sodium tungstate can also be produced by treating tungsten carbide with a mixture of sodium nitrate and sodium hydroxide in a fusion process which overcomes the high exothermicity of the reaction involved.
Профиль безопасности
Poison by ingestion, intravenous, intramuscular, and subcutaneous routes. Experimental reproductive effects. Mutation data reported. When heated to decomposition it emits toxic fumes of Na2O. See also TUNGSTEN COMPOUNDS.
Вольфрамат натрия (VI) препаратная продукция и сырье
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