The hydroxide anion is a negatively charged species (OH-) that consists of one oxygen atom and one hydrogen atom. It is formed when bases dissociate in water.
Related terms
Hydronium ion: A positively charged species (H3O+) that forms when acids donate protons to water molecules.
Acid-base indicator: A substance that changes color depending on whether it is in an acidic or basic environment.
pH scale: A logarithmic scale used to specify the acidity or basicity (alkalinity) of an aqueous solution.