Several techniques have been used to study the structure of the Keggin-type polyoxometalate salt ammonium metatungstate(AMT)—(NH4)6[H2W12O40]*nH2O, a potential fuel cell catalyst. The dehydrated salt is comprised of a mixture of crystallites of different unit cells in a centered eutactic cubic configuration, with an average unit cell of a≅12.295. Varied orientations of the Keggin ions in the cubic arrangement create the differences, and orientational variation within each unit cell size represents an energy well.

Tungsten has a rich history dating back to its discovery during the 18th century. Peter Woulfe was the first to recognize a new element in the naturally occurring mineral wolframite. Tungsten was originally known as wolfram, explaining the choice of "W" for its elemental symbol. Swedish chemist Carl Wilhelm Scheele contributed to its discovery as well with his studies on the mineral scheelite.

In 1841, a chemist named Robert Oxland gave the first procedures for preparing tungsten trioxide and sodium tungstate.He was granted patents for his work soon after, and is considered to be the founder of systematic tungsten chemistry.

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Using a coupling process of neutralization–nanofiltration–crystallization, pure  is producted . The effects of chemical neutralization of ammonium paratungstate (APT) by nitric acid, operating pressure, the concentration of AMT and the volume of washing water on the coupling process were systematically discussed. It was found that the better conditions of AMT