The xenonium ion, XeH<sup>+</sup>, is an onium compound, consisting of protonated xenon. Although the existence of the xenonium salts has not been proven, the isolated XeH<sup>+</sup> ion is known. Salts of the fluoroxenonium ion, XeF<sup>+</sup>, are known to exist, for instance fluoroxenonium pentafluoroplatinate (XeFPtF<sub>5</sub>), more commonly known as xenon hexafluoroplatinate.