Xenon dioxide

Structure

has an extended (chain or network) structure in which xenon and oxygen have coordination numbers of four and two respectively. The geometry at xenon is square planar, consistent with VSEPR theory for four ligands and two lone pairs (or AX4E2 in the notation of VSEPR theory).

The XeO2 network does not share a crystal structure of SiO2 (which has tetrahedral coordination at Si), but XeO2 units are believed to intermix with SiO2 in Earth's mantle. Computational studies suggest that xenon cannot displace silicon directly, but can fill pre-existing silicon vacancies. The stability of the resulting material under standard conditions depends on its allotrope. Patterned off quartz, it likely decomposes; but materials patterned off fibrous silica may be metastable.

In addition, the existence of an XeO2 molecule was predicted by an ab initio quantum chemistry method several years earlier by Pyykkö and Tamm, but these authors did not consider an extended structure.

Properties

is a yellow-orange solid.{{cite magazine |url=https://eic.rsc.org/soundbite/xenon-dioxide/2021269.article |last=Cotton |first=Simon |title=Xenon dioxide

At -78 °C, the majority of XeO2 decomposed over a period of 72 hours, which was identified by the fading of the original yellow product to a pale yellow. Almost all yellow color indicating pure XeO2 disappeared over the span of 1 week.

:3 XeO2 → Xe + 2 XeO3

References

References

1. (2011). "Synthesis of the Missing Oxide of Xenon, XeO₂, and Its Implications for Earth's Missing Xenon". Journal of the American Chemical Society.
2. "The Chemistry of Xenon(IV)". Chemical Reviews.
3. Pyykkö, Pekka. (1 April 2000). "Calculations for XeO_n(n = 2−4): Could the Xenon Dioxide Molecule Exist?". The Journal of Physical Chemistry A.
4. Tyler Irving. (May 2011). "Xenon Dioxide May Solve One of Earth's Mysteries". L’Actualité chimique canadienne (Canadian Chemical News).