Wikipedia
Xenonium
The xenonium ion, XeH, is an onium compound, consisting of protonated xenon. Although the existence of the xenonium cation itself has not been proven, salts of the fluoroxenonium ion, XeF, are known to exist, for instance fluoroxenonium pentafluoroplatinate (XeFPtF), more commonly known as xenon hexafluoroplatinate.