Solvated electron: Difference between revisions

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Revision as of 02:45, 26 January 2016

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Focusing on ammonia solutions, all of the alkali metals, as well as [[calcium|Ca]], [[strontium|Sr]], [[barium|Ba]], [[europium|Eu]], and [[ytterbium|Yb]] (also [[magnesium|Mg]] using an electrolytic process<ref>C. Combellas, F. Kanoufi, A. Thiebault, ''J. Electroanalytical Chem'' 499(1), 144-151 (2001) {{DOI|10.1016/S0022-0728(00)00504-0}}</ref>), dissolve to give the characteristic blue solutions. Other amines, such as [[methylamine]] and [[ethylamine]], are also suitable solvents.<ref>{{Greenwood&Earnshaw2nd}}</ref>

A lithium ammonia solution at −60&nbsp;°C is saturated at about 16&nbsp;mol% metal (16&nbsp;MPM in the local jargon). When the concentration is increased in this range [[electrical conductivity]] increases from 10⁻² to 10⁴&nbsp;[[ohm]]⁻¹[[Centimetre|cm]]⁻¹ (larger than liquid [[mercury (element)|mercury]]). At around 8&nbsp;MPM, a "transition to the metallic state" (TMS) takes place (also called a "metal to nonmetal transition" (MNMT)). At 4&nbsp;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&nbsp;MPM all electrons are [[Electron pair|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.