Sodium tungstate

Sodium tungstate Basic information
Product Name:Sodium tungstate
Synonyms:AMMONIUM TUNGSTATE (PARA);AMMONIUM WOLFRAMATE;SODIUM O-TUNGSTATE;SODIUM PARA-TUNGSTATE;W HC 40;TUNGSTEN AA SINGLE ELEMENT STANDARD;TUNGSTEN, AAS STANDARD SOLUTION;TUNGSTEN AA STANDARD
CAS:13472-45-2
MF:Na2WO4
MW:293.82
EINECS:236-743-4
Product Categories:Inorganics
Mol File:13472-45-2.mol
Sodium tungstate Structure
Sodium tungstate Chemical Properties
Melting point 3410 °C(lit.)
Boiling point 5660 °C(lit.)
density 2.3 g/mL at 25 °C(lit.)
vapor pressure 0Pa at 25℃
solubility H2O: soluble
form wire
pka3.5[at 20 ℃]
Water Solubility g/100g H2O: 71.5 (0°C), 73.0 (20°C), 97.2 (100°C) [LAN05]
Merck 13,8772
LogP0
CAS DataBase Reference13472-45-2(CAS DataBase Reference)
EPA Substance Registry SystemSodium tungsten oxide (Na2WO4) (13472-45-2)
Safety Information
Hazard Codes Xi
Risk Statements 36/38
Safety Statements 6-26-36
RIDADR UN 3089 4.1/PG 2
WGK Germany 3
RTECS YO7175000
HazardClass 6.1(b)
PackingGroup III
Hazardous Substances Data13472-45-2(Hazardous Substances Data)
MSDS Information
ProviderLanguage
SigmaAldrich English
ACROS English
ALFA English
Sodium tungstate Usage And Synthesis
Chemical PropertiesSodium 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.
UsesIntermediate in preparation of tungsten compounds, (e.g., phosphotungstate), reagent, fire-proofing fabrics and cellulose, alkaloid precipitant.
DefinitionChEBI: 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.
PreparationSodium 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.
Flammability and ExplosibilityNotclassified
Safety ProfilePoison 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.
BISMUTH TUNGSTATE copper(ii) tungstate hydrate LEAD MOLYBDATE BARIUM TUNGSTATE CADMIUM TUNGSTATE Calcium tungstate ALUMINUM TUNGSTATE MAGNESIUM TUNGSTATE Sodium tungstate dihydrate SODIUM METATUNGSTATE Ammonium paratungstate Tungstic acid SODIUM PHOSPHOTUNGSTATE Tungsten SODIUM TUNGSTATE AMMONIUM WOLFRAMATE PENTAHYDRATE

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