Xenon hexafluoroplatinate

Xenon hexafluoroplatinate is the description of the product obtained from the combination of platinum hexafluoride and xenon in an experiment that proved the chemical reactivity of the noble gases. Neil Bartlett at the University of British Columbia formulated the product as "Xe+[PtF6]&minus;", although subsequent work suggests that Bartlett's product was probably a mixture and did not in fact contain this specific salt.

Preparation
"Xenon hexafluoroplatinate" is prepared from xenon 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]&minus;. 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. Further work indicates that Bartlett's product probably contained [XeF+][PtF6]&minus;, [XeF+][Pt2F11]&minus;, [Xe2F3+][PtF6&minus;]. The title "compound" is a salt, consisting of an octahedral anionic fluoride complex of platinum and various xenon cations.

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.

History
In 1962, Neil Bartlett discovered that a mixture of platinum hexafluoride gas and oxygen formed a red solid. The red solid turned out to be dioxygenyl hexafluoroplatinate, O2+[PtF6]-. Bartlett later surmised 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", whereupon he established that xenon indeed reacts with PtF6. Although, as discussed above, the product was probably highly impure, Bartlett's work was the first proof that compounds could be prepared from a noble gas. His discovery illustrates that the finding of new chemical methods often lead initially to impure products. Since Bartlett's observation, many well-defined compounds of xenon have been reported including XeF2, XeF4, and XeF6.