Chromium hexafluoride

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.

References

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

Binary hexafluorides

Known binary hexafluorides

Chalcogen binary hexafluorides	SF₆ SeF₆ TeF₆ PoF₆
Noble gas binary hexafluorides	XeF₆
Transition metal binary hexafluorides	MoF₆ TcF₆ RuF₆ RhF₆ WF₆ ReF₆ OsF₆ IrF₆ PtF₆
Actinide binary hexafluorides	UF₆ NpF₆ PuF₆

Predicted binary hexafluorides

Noble gas binary hexafluorides	KrF₆ RnF ₆
Transition metal binary hexafluorides	CrF₆ PdF₆ AuF₆
Actinide binary hexafluorides	AmF₆ CmF₆ EsF₆