The pentafluoroxenate(IV) anion, XeF5-: the first example of a pentagonal planar AX5 species

C6F5XeF, a versatile starting material in xenon–carbon chemistry

“…This exchange which is known e.g. from the [XeF 5 ] À anion [11] can be suppressed by adding small quantities of a soluble fluoride like [NMe 4 ] F and has a significant effect on the shape of the o-F signal (Figs. 1 and 2).…”

Phenyliodine(V) fluorides

“…Such pentagonal molecular geometries are rare, but not without precedent. Two relevant example are XeF 5 À [16] and IF 5 2À [17]. Even more relevant are the chemically similar anions XeOF 5 À [18,19] and IOF 5 2À [20] that have the same pentagonal-pyramidal structure.…”

Mean amplitudes of vibration of molecules and ions with interhalogen bonds and related species

“…, which have also been observed in the case of the isoelectronic XeF 5 À anion [84], suggests relatively weak bonds, undoubtedly related to an important congestion effect on the molecular plane, in which the fluorine atoms are practically in contact [81,84]. -The impact of a geometrical effect can also be seen by the comparison of trans-F 5 IO 2 2À and trans-F 4 IO 2 À , in which the increment of the mean amplitude values in the first case, can be mainly attributed to the congestion effect in the equatorial IF 5 plane.…”

“…The first example of a chemical species adopting the unusual pentagonal-planar geometry was the XeF 5 À anion, characterized in 1991 [81], and some years later the isoelectronic IF 5 2À was also reported [82] and its mean amplitudes of vibration calculated [83]. The results of these calculations are shown in Table 14.…”