Paratungstate

In chemistry, paratungstate refers to the anion with the formula [W₁₂O₄₂]^12- and salts derived from this anion. The term also refers to protonated derivatives of this anion, including [H₂W₁₂O₄₂]^10-. Ammonium paratungstate (or APT), (NH₄)₁₀[H₂W₁₂O₄₂] is a key intermediate in the purification of tungsten from its ores.{{Ullmann|title=Tungsten, Tungsten Alloys, and Tungsten Compounds|first1 =Erick|last1=Lassner|first2=Wolf-Dieter|last2=Schubert|first3=Eberhard|last3=Lüderitz|first4=Hans Uwe|last4=Wolf||year=|2005|doi=10.1002/14356007.a27_229}}

File:EntryWithCollCode15237.png

The salt (NH₄)₁₀(W₁₂O₄₂)·4H₂O has been characterized by X-ray crystallography.{{cite journal|doi=10.1524/zkri.1972.136.1-2.23|title=Die Kristallstruktur des Ammoniumparawolframat-tetrahydrats (NH₄)₁₀[H₂W₁₂O₄₂]·4H₂O|journal=Zeitschrift für Kristallographie|volume=136|issue=1–2|pages=23–47|year=1972|last1=d'Amour|first1=Hedwig|last2=Allmann|first2=Rudolf|bibcode=1972ZK....136...23D}}

The unprotonated anion [W₁₂O₄₂]^12- has C_2h symmetry.