Tetramethylammonium pentafluoroxenate
IUPAC name
Tetramethylammonium pentafluoridoxenonate(−)
3D model (JSmol)
  • InChI=1S/C4H12N.F5Xe/c1-5(2,3)4;1-6(2,3,4)5/h1-4H3;/q+1;-1
  • C[N+](C)(C)C.F[Xe-](F)(F)(F)F
Molar mass 300.4308 g/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Tetramethylammonium pentafluoroxenate is the chemical compound with the formula N(CH3)4XeF5. The XeF
ion it contains was the first example of a pentagonal planar molecular geometry AX5E2 species.[1] It was prepared by the reaction of N(CH3)4F with xenon tetrafluoride, N(CH3)4F being chosen because it can be prepared in anhydrous form and is readily soluble in organic solvents.[1] The anion is planar, with the fluorine atoms in a slightly distorted pentagonal coordination (Xe–F bond lengths 197.9–203.4 pm, and F–X–F bond angles 71.5°–72.3°).[1] Other salts have been prepared with sodium, cesium and rubidium, and vibrational spectra show that these contain the same planar ion.[1] The isolated anion has the point group of D5h.[1]

Ball-and-stick model of the pentafluoroxenate ion
Structural formula of the pentafluoroxenate ion


  1. ^ a b c d e Christe, K. O.; Curtis, E. C.; Dixon, D. A.; Mercier, H. P.; Sanders, J. C. P.; Schrobilgen, G. J. (1991). "The pentafluoroxenate(IV) anion, XeF
    : the first example of a pentagonal planar AX5 species". Journal of the American Chemical Society. 113 (9): 3351–3361. doi:10.1021/ja00009a021.