Rhenium heptafluoride

Rhenium heptafluoride is the compound with the formula ReF₇. It is a yellow low melting solid, and is the only thermally stable metal heptafluoride. It has a distorted pentagonal bipyramidal structure similar to IF₇, which was confirmed by neutron diffraction at 1.5K. The structure is non-rigid as evidenced by electron diffraction studies.

It can be prepared from the elements at 400 °C:

With fluoride donors such as CsF, the ReF₈⁻ anion is formed, which has a square antiprismatic structure. With antimony pentafluoride, SbF₅, a fluoride acceptor, the ReF₆⁺ cation is formed.