Molecular ion

In the International Union of Pure and Applied Chemistry (IUPAC) mass spectrometry convention, a molecular ion is formed by removing or adding one or more Electrons to a molecule without fragmentation of its molecular structure.^[ref] For example, removing one Electron from intact water gives ${\mathrm{H}}_2{\mathrm{O}}^{\bullet +}$: two hydrogen and one oxygen chemical atom, total electric charge $+e$, and an unpaired Electron, hence a radical cation. Atom inventory, net electric charge, and electronic state are separate pieces of information. Hydronium, ${\mathrm{H}}_3{\mathrm{O}}^{+}$, has a different inventory; it is a polyatomic ion, rather than the molecular ion obtained by electron removal from water.