XeF4XeF6

XeF4XeF6 is a crystalline adduct formed from xenon tetrafluoride (XeF4) and xenon hexafluoride (XeF6) in approximately a 1:1 ratio. In this co-crystal, discrete XeF4 and XeF6 units coexist within a single lattice, with the overall compound remaining neutral. The bonding between the two units is not covalent; instead, the solid is stabilized by intermolecular fluorine–fluorine contacts and halogen-bonding interactions between the fluoride ligands of the two xenon fluorides.

The adduct is typically prepared by slow co-crystallization of XeF4 and XeF6 under strictly inert and moisture-free conditions, often from fluorinated solvents or melts. X-ray crystallography has been used to characterize the structure, showing an ordered arrangement of XeF4 and XeF6 units in the crystal lattice and revealing short F···F contacts that link the molecules into a solid network. The compound serves as a clear example of how noble-gas fluorides can form stable solid-state adducts through noncovalent interactions.

Stability and handling are largely determined by the solid-state environment. The XeF4XeF6 adduct is sensitive to moisture and heat; exposure to water or proton sources leads to hydrolysis of the fluorides, producing xenon-oxide/hydrogen fluoride–type decomposition products. As a result, the compound is studied primarily for fundamental insights into halogen bonding, fluoride transfer, and the coordination chemistry of xenon fluorides rather than for practical applications.

See also: xenon difluoride (XeF2), xenon tetrafluoride (XeF4), xenon hexafluoride (XeF6), noble gas compounds.