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