Meaning of hydroxonium ion in English:

hydroxonium ion

Pronunciation /ˌhʌɪdrɒkˈsəʊnɪəm/


  • The ion H₃O⁺, consisting of a protonated water molecule and present in all aqueous acids.

    ‘Further down this page, we shall calculate the concentration of hydroxonium ions present in pure water.’
    • ‘The trajectories of movement of the hydroxyl and hydroxonium ions are cycloids.’
    • ‘One assumes that it is the hydroxonium ions but is this necessarily the case?’
    • ‘When acetic acid dissociates in water it loses hydrogen to form the hydroxonium ion, H 3 O +, and the acetate ion.’
    • ‘The complex ion is deprotonated, causing the solution to be acidic from the formation of hydroxonium ions H 3 O +.’


1920s hydroxonium from hydro-(relating to hydrogen) + oxy- + the suffix -onium (from ammonium).