polianion

Polyanion is a term used in chemistry to describe an anion containing more than one atom. This distinguishes polyanions from monoatomic anions, which consist of only a single atom. Polyanions are formed when a neutral molecule or atom gains two or more electrons, resulting in a net negative charge. The specific atoms involved and their arrangement determine the properties and stability of the polyanion. Common examples include sulfate (SO4^2-), phosphate (PO4^3-), and carbonate (CO3^2-). These ions are prevalent in many natural and synthetic compounds, playing crucial roles in biological systems, mineral formation, and industrial processes.

The structure of polyanions can vary significantly. Some are simple, with a central atom bonded to several surrounding atoms, like the tetrahedral structure of sulfate and phosphate. Others can be more complex, involving chains or rings of atoms. The charge of a polyanion is determined by the number of electrons gained and the formal charges of the constituent atoms. Understanding the structure and charge of polyanions is essential for predicting their reactivity, solubility, and interactions with other chemical species. They are often stabilized by electrostatic interactions with surrounding cations.