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.
