Octafluoride

An octafluoride is a compound or ion with the formula [M_mR_nF₈]^q− or [M_mR_nF₈]^q+, where n, m and q are independent variables and R any substituent and M is a central element (often a metal). All of the examples listed below are [MF₈]^q− with q between 1 and 4 inclusive.

Neutral octafluorides

No electrically neutral octafluorides are currently known to exist, although osmium octafluoride, OsF₈, is theoretically possible. An early report of the synthesis of OsF₈ was much later shown to be a mistaken identification of OsF₆.[1]

Anionic octafluorides

In contrast, many anionic octafluorides are known, such as the octafluorozirconate(IV) ([ZrF₈]^4−), octafluorotantalate(V) ([TaF₈]^3−), octafluoroniobate(V) ([NbF₈]^3−),[1] octafluoromolybdate(VI) ([MoF₈]^2−),[1] octafluorotungstate(VI) ([WF₈]^2−),[1] octafluororhenate(VII) ([ReF₈]^−),[1] octafluoroiodate(VII) ([IF₈]^−), octafluoroiridate(VII) ([IrF₈]^−),[2] and octafluoroxenate(VI) ([XeF₈]^2−) anions.

References

1. Riedel, S.; Kaupp, M. (30 Jul 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.
2. Jianyan Lin, Ziyuan Zhao, Chunyu Liu, Jing Zhang, Xin Du, Guochun Yang, and Yanming Ma (March 13, 2019). "IrF8 Molecular Crystal under High Pressure". J. Am. Chem. Soc. 141 (13): 5409–5414. doi:10.1021/jacs.9b00069. PMID 30864432. S2CID 76664353.