Octafluoride

An octafluoride is a compound or ion with the formula RnMxF8y− or RnMxF8y+, where n, x, and y are independent variables and R any substituent.
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.
Anionic octafluorides.
In contrast, many anionic octafluorides are known, such as the octafluorozirconate (ZrF84−), octafluorotantalate (TaF83−), octafluoromolybdate (MoF82−), octafluorotungstate (WF82−), octafluororhenate (ReF8−), octafluoroiodate (IF8−), and octafluoroxenate (XeF82−) anions.