Hexafluoride

An important hexafluoride is hexafluorosilicic acid (H2SiF6), which is a byproduct of the mining of phosphate rock.

In the nuclear industry, uranium hexafluoride (UF6) is an important intermediate in the purification of this element.

Four hexafluorides (S, Se, Te, and W) are gases at room temperature (25 °C) and a pressure of 1 atm, two are liquids (Re, Mo), and the others are volatile solids.

The molecular geometry of binary hexafluorides is generally octahedral, although some derivatives are distorted from Oh symmetry.

For the main group hexafluorides, distortion is pronounced for the 14-electron noble gas derivatives.

According to quantum chemical calculations, ReF6 and RuF6 should have tetragonally distorted structures (where the two bonds along one axis are longer or shorter than the other four), but this has not been verified experimentally.

In contrast, metal hexafluorides are corrosive, readily hydrolyzed, and may react violently with water.

The metal hexafluorides have a high electron affinity, which makes them strong oxidizing agents.

Tungsten hexafluoride is used in the production of semiconductors through the process of chemical vapor deposition.

[12] The ionicity of the Rn–F bond may also result in a strongly fluorine-bridged structure in the solid, so that radon fluorides may not be volatile.