Formation and Decomposition of Potassium Potassides Complexed Crown Ethers in Tetrahydrofuran Solution

This review systematizes the essential data on alkalide solutions called also alkali metal solutions or blue solutions, i.e. solutions of the salts containing alkali metal anions (M-). It focuses particularly on the formation and decomposition of potassium potassides as well as on the equilibrium and non-equilibrium reactions occurring with the participation of solvated electrons (e-), potassium anions (K-) and potassium cations complexed crown ethers (K+Ln, where n = 1 or 2). An explanation is proposed of the puzzling constancy of [e-] while [K-] decreases in apparent contradiction of the law of mass action in the reaction with an oxidant or during the self-decomposition of the solution.