An octafluoride is a compound or ion with the formula or, 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 with q between 1 and 4 inclusive.
No electrically neutral octafluorides are currently known to exist, although osmium octafluoride,, is theoretically possible. An early report of the synthesis of was much later shown to be a mistaken identification of .[1]
In contrast, many anionic octafluorides are known, such as the octafluorozirconate(IV), octafluorotantalate(V), octafluoroniobate(V), octafluoromolybdate(VI), octafluorotungstate(VI), octafluororhenate(VII), octafluoroiodate(VII), octafluoroiridate(VII),[2] and octafluoroxenate(VI) anions.