Tungstate

As tungstates the salts of tungstic acid are known. They are chemically related to the chromates and molybdates.

Tungstates are known in various ratios between acid and bases, the simplest form of the Ortho tungstate WO42 - is. Previously, the salts were divided according to the ratio, the salts of the acid paratungstic also Para tungstates and the pertungstic Perwolframate were called, with also other forms such as Isowolframsäure, metatungstic or polytungstic existed by name.

In addition to the sodium paratungstenate Na10W12O41 28 H2O and potassium tungstate K2WO4 that serves as a fire retardant for wood and flammable materials, also as a mordant in dyeing, find many salts as a painter paints applied, nickel tungstate NiWO4 (green ), chromium tungstate ( green), cobalt tungstate ( violet), Zinnwolframat ( indigo blue), barium tungstate BaWO4 ( tungsten white ) and iron tungstate FeWO4 ( chamois ). Furthermore, ammonium tungstate ( NH4) 10W12O41 and sodium tungstate Na2WO4 serve as a catalyst in organic synthesis. Magnesium tungstate MgWO4 and especially lead tungstate PbWO4 be used as a modern scintillator in particle physics. Concentrated solutions of sodium polytungstate (3 Na2WO4 · 9 WO3 · H2O ) are used as heavy liquid because of their high density.

Of course tungstates come in the form of the mineral scheelite (calcium tungstate CaWO4 ), wolframite (mixed crystal), Ferberite (iron tungstate ), Hübnerit ( manganese tungstate ), Sanmartinit (iron -zinc tungstate solid solution ), Stolzit (lead tungstate ), Krasnoselskit ( cobalt tungstate ) and some other before.