Chromium hexafluoride explained

Chromium hexafluoride or chromium(VI) fluoride (CrF₆) is a hypothetical chemical compound between chromium and fluorine with the chemical formula CrF₆. It was previously thought to be an unstable yellow solid decomposing at −100 °C,^[1] but this has been shown to be a misidentification of chromium pentafluoride, CrF₅.^[2]

Unsuccessful attempts at synthesis

CrF₆ used to be thought to be produced by exhaustive fluorination of chromium metal at 400 °C and 20 MPa of pressure, and immediate freezing out of the reaction chamber to prevent decomposition:

Cr + 3 F₂ → CrF₆

However, it has been shown that chromium pentafluoride (CrF₅) is formed instead:

2 Cr + 5 F₂ → 2 CrF₅

and that CrF₆ has yet to be synthesized.

Notes and References

1. 10.1021/ic00026a002. Is chromium hexafluoride octahedral? Experiment still suggests "yes!". 1991. Hope. Eric G.. Levason. William.. Ogden. J. Steven. Inorganic Chemistry. 30. 26. 4873.
2. Riedel . Sebastian . Kaupp . Martin . 2009 . The highest oxidation states of the transition metal elements . Coordination Chemistry Reviews . 253 . 5–6 . 10.1016/j.ccr.2008.07.014 . 606–624.