Assertion: hydrogen fluoride's impurity | /r/AtLocation | the form of various compounds
Facets:
Source sentences:
text: Boron, silicon, phosphorus, sulfur and chlorine present as impurities in hydrofluoric acid are in the form of various compounds which chiefly include HBF 4 , H 2 SiF 6 , HPF 6 , HSO 3 F and HCl.