Tungstate

Ammonium paratungstate is produced separating tungsten from its ore. Once the ammonium paratungstate is prepared, it is heated to its decomposition temperature, 600 °C. Left over is WO3, tungsten(VI) oxide. From there, the oxide is heated in an atmosphere of hydrogen, reducing the tungsten to elemental powder, leaving behind water vapor.

Scheelite is a calcium tungstate mineral with the chemical formula CaWO4. It is an important ore of tungsten. Well-formed crystals are sought by collectors and are occasionally fashioned into gemstones when suitably free of flaws. Scheelite has been synthesized via the Czochralski process; the material produced may be used to imitate diamond, as a scintillator, or as a solid state lasing medium.

A silvery, moderately hard metallic element that constitutes approximately 3 percent of the earth's crust and is a basic component of most animals and plants. It occurs naturally in limestone, gypsum, and fluorite, and its compounds are used to make plaster, quicklime, portland cement, and metallurgic and electronic materials. Atomic number 20; atomic weight 40. 08; melting point 842 to 848°c; boiling point 1,487°c; specific gravity 1. 55; valence 2.

Potassium Tungstate is one of numerous organo-metallic compounds sold by American Elements under the tradename AE Organo-Metallics™ for uses requiring non-aqueous solubility such as recent solar energy and water treatment applications.

Sodium tungstate, Na2WO4, a tungstate of sodium, is useful as a source of tungsten. It is prepared from tungsten ores used to manufacture tungsten by reducing it.It is often found as the dihydrate, Na2WO4•2H2O. This salt is soluble in water and is a moderately strong oxidizing agent, but finds no common use in the chemistry laboratory. Like the molybdate, the deep-coloured complex tungstate(VI,V) is formed on reducing the compound with a very mild reducing agent, such as complex organic compounds.

Zr(wo4)2, or zirconium tungstate is a metal oxide with unusual properties. The phase formed at ambient pressure by reaction of zro2 and wo3 is a metastable cubic phase, which has negative thermal expansion characteristics, namely it shrinks over a wide range of temperatures when heated. [1]

Ammonium paratungstate is a white crystalline salt of ammonium and tungsten, with the chemical formula (NH4)10(W12O41)·5H2O.Ammonium paratungstate is produced separating tungsten from its ore. Once the ammonium paratungstate is prepared, it is heated to its decomposition temperature, 600 °C. Left over is WO3, tungsten(VI) oxide. From there, the oxide is heated in an atmosphere of hydrogen, reducing the tungsten to elemental powder, leaving behind water vapor.