Tellurium Hexafluoride, TeF₆

Tellurium Hexafluoride, TeF₆, appears to be more stable than tellurium tetrafluoride. It has been obtained by the action of fluorine on tellurium at -78° C. The resulting colourless crystalline solid vaporises on allowing the temperature to rise. The solidified substance melts at -36° C. and boils at -35.5° C., the critical temperature being 83° C. The vapour density is 119.5, agreeing with the formula TeF₆. The gas has an unpleasant odour, recalling ozone and tellurium hydride. Water only slowly decomposes the gas, which does not attack glass.

TeF₆ + 4H₂O = H₂TeO₄ + 6HF.