A solvated electron is a free electron in a solution, in which it behaves like an anion.[1] An electron's being solvated in a solution means it is bound by the solution.[2] The notation for a solvated electron in formulas of chemical reactions is "e−". Often, discussions of solvated electrons focus on their solutions in ammonia, which are stable for days, but solvated electrons also occur in water and many other solvents – in fact, in any solvent that mediates outer-sphere electron transfer. The solvated electron is responsible for a great deal of radiation chemistry.