As illustrated by [Pb₂(OH)]³⁺, metal hydroxides are often written in a simplified format. It can even act as a 3-electron-pair donor, as in the tetramer [PtMe₃(OH)]₄.

When bound to a strongly electron-withdrawing metal centre, hydroxide ligands tend to ionise into oxide ligands. For example, the bichromate ion [HCrO₄]^- dissociates according to
:[O₃CrO-H]^- [CrO₄]^2- + H⁺with