WS2 + 4HF + 18HNO3 → H2[WO2F4] + 18NO2 + 2H2SO4 + 8H2O
Tungsten(IV) sulfide react with hydrogen fluoride and nitric acid to produce hydrogen tetrafluorodioxotungstate(VI), nitrogen dioxide, sulfuric acid and water. Sulfuric acid and hydrogen fluoride - concentrated solutions.