Worlds of David Darling
Encyclopedia of Science
Home > Encyclopedia of Science

hydrogen ion

A hydrogen ion is a hydrogen atom that has lost or gained an electron, and in consequence has a charge. The positive hydrogen ion (H+), having lost its only electron, consists of just a proton.

Chemically free hydrogen ions are rarely formed and dissociation to H+ occurs only when the resultant ion can be complexed. Thus hydrogen chloride (HCl) gas is undissociated but gives [H(H2O)n]+Cl- and [NH4]+Cl- with water or ammonia.

Related category