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A solvated electron is a free electron in (solvated in) a solution, and is the smallest possible anion. Solvated electrons occur widely although they are often not observed directly. The deep color of solutions of alkali metals in ammonia arises from the presence of solvated electrons: blue when dilute and copper-colored when more concentrated (> 3 molar). Classically, discussions of solvated electrons focus on their solutions in ammonia, which are stable for days, but solvated electrons occur in water and other solvents, in fact, any solvent that mediates outer-sphere electron transfer. The solvated electron is responsible for a great deal of radiation chemistry. ==Properties== Focusing on ammonia solutions, all of the alkali metals, as well as Ca, Sr, Ba, Eu, and Yb (also Mg using an electrolytic process〔C. Combellas, F. Kanoufi, A. Thiebault, ''J. Electroanalytical Chem'' 499(1), 144-151 (2001) 〕), dissolve to give the characteristic blue solutions. Other amines, such as methylamine and ethylamine, are also suitable solvents. A lithium ammonia solution at −60 °C is saturated at about 16 mol% metal (16 MPM in the local jargon). When the concentration is increased in this range electrical conductivity increases from 10−2 to 104 ohm−1cm−1 (larger than liquid mercury). At around 8 MPM, a "transition to the metallic state" (TMS) takes place (also called a "metal to nonmetal transition" (MNMT)). At 4 MPM a liquid-liquid phase separation takes place: the less dense gold-color phase becomes immiscible from a more dense blue phase. Above 8 MPM the solution is bronze/gold-colored. In the same concentration range the overall density decreases by 30%. Dilute solutions are paramagnetic and at around 0.5 MPM all electrons are paired up and the solution becomes diamagnetic. Several models exist to describe the spin-paired species: as an ion trimer, or as an ion-triple—a cluster of two single-electron solvated-electron species in association with a cation, or as a cluster of two solvated electrons and two solvated cations. Solvated electrons produced by dissolution of reducing metals in ammonia and amines are the anions of salts called electrides. Such salts can be isolated by the addition of macrocyclic ligands such as crown ether and cryptands. These ligands bind strongly the cations and prevent their re-reduction by the electron. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Solvated electron」の詳細全文を読む スポンサード リンク
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