Lyonium ion
# Lyonium ion

In chemistry, a lyonium ion is the cation derived by the protonation of a solvent molecule. For example, a hydronium ion is formed by the protonation of water, and $CH_3OH+2$ is the cation formed by the protonation of methanol.

Its counterpart is a lyate ion, the anion formed by the deprotonation of a solvent molecule.

Lyonium and lyate ions, resulting from molecular autoionization, contribute to the molar conductivity of protolytic solvents.

## Examples

| Lyate ion | Lyate ion | Original solvent | Original solvent | Lyonium ion | Lyonium ion |
| - | - | - | - | - | - |
| name | formula | name | formula | name | formula |
| Fluoride | $F^−$ | Hydrogen fluoride | HF | Fluoronium | $H_2F^+$ |
| Hydroxide | $HO^−$ | Water | $H_2O$ | Hydronium | $H_3O^+$ |
| Azanide | NH−2 | Ammonia | $NH_3$ | Ammonium | NH+4 |
| Methanide | CH−3 | Methane | $CH_4$ | Methanium | CH+5 |
| Methoxide | $CH_3O^−$ | Methanol | $CH_4O$ | Methyloxonium | $CH_5O^+$ |
