Xenon hexafluoroplatinate

Additional recommended knowledge

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Preparation

"Xenon hexafluoroplatinate" is prepared from Xe and platinum hexafluoride (PtF₆) as gaseous solutions in SF₆. The reactants were combined at 77K and slowly warmed, presumably to allow for a controlled reaction.

Structure

The structure of "xenon hexafluoroplatinate" is likely not Xe⁺[PtF₆]⁻. The main problem with this formulation is "Xe⁺", which would be a radical and would dimerize or abstract an F atom to give XeF⁺. Thus, Bartlett discovered that Xe undergoes chemical reactions, but the nature of his initial mustard yellow product is complex.^[1] Further work indicates that Bartlett's product probably contained [XeF⁺][PtF₆]⁻, [XeF⁺][Pt₂F₁₁]⁻, [Xe₂F₃⁺][PtF₆⁻].^[2] The title "compound" is a salt, consisting of an octahedral anionic fluoride complex of platinum and various xenon cations.^[3]

It has been proposed that the platinum fluoride forms a negatively charged polymeric network with xenon or xenon fluoride cations held in its instices. A preparation of "XePtF₆" in HF solution results in a solid which has been characterized as a [PtF₅^-]_n polymeric network associated with XeF⁺. This result is evidence for such a polymeric structure of xenon hexafluoroplatinate.^[1]

History

Main article: Noble gas compound

In 1962, Neil Bartlett discovered that a mixture of platinum hexafluoride gas and oxygen formed a red solid.^[4][5] The red solid turned out to be dioxygenyl hexafluoroplatinate, O₂⁺[PtF₆]^-. Bartlett later surmized that the ionization energies for O₂ molecule and Xe were similar. He then asked his colleagues to give him some xenon "so that he could try out some reactions",^{[citation needed]} whereupon he established that xenon indeed reacts with PtF₆. Although, as discussed above, the product was probably highly impure, Bartlett's discovery was the first proof that compounds could be prepared from a noble gas. His discovery illustrates that the discovery of new chemical methods often lead Initially to impure products. Since Bartlett's discovery, many well-defined compounds of xenon have been reported including XeF₂, XeF₄, and XeF₆.

References