Hydronium

In chemistry, a hydronium ion is the cation H₃O+, a type of oxonium ion produced by protonation of water. This cation is often used to represent the nature of the proton in aqueous solution, where the proton is highly solvated (bound to a solvent). The reality is far more complicated, and a proton is bound to several molecules of water, such that other descriptions such as H₅O₂+, H₇O₃+ and H₉O₄+ are increasingly accurate descriptions of the environment of a proton in water. The ion H₃O+ has been detected in the gas phase.