Anionion

Anionion is a term that has appeared in speculative chemistry and fictional contexts to describe a class of negatively charged ionic species. In real-world chemistry there is no recognized entity known as an anionion, and the word is not part of standard nomenclature. When used, it is typically introduced as a hypothetical or engineered ion to explore concepts in charge, stability, and ion–solvent interactions.

In theoretical or narrative uses, anionion is imagined as an anion with unusually high charge density or extensive delocalization across a polyatomic framework. Such a species might be envisioned as existing only under specialized conditions, such as highly coordinating solvents, extreme pressures, or strong counterion environments. Discussions may touch on its potential effects on lattice energies, hydration shells, and electrostatic screening, as well as the challenges of stabilizing multiple negative charges without rapid decay or aggregation.

Because the term is not standard, descriptions of anionion vary by author and context. It is most often employed as a thought experiment to probe how traditional models of ionic behavior hold up when faced with atypical charge distributions, or as a fictional device to imagine advanced materials or chemical architectures.

See also: Anion, Cation, Polyatomic ion, Ionic bond, Electrostatics.