Wiktionary
silicotungstic acid
n. (context organic compound English) The most commonly encountered heteropoly acid, widely used in heterogeneous catalysts.
Wikipedia
Silicotungstic acid
Silicotungstic acid (also known as tungstosilicic acid) is the most commonly encountered heteropoly acid. It is a pale yellow solid with the chemical formula H[WSiO]. It is used as a catalyst in the chemical industry.