The work is devoted to the theoretical and experimental study of the electrochemical characteristics of the closo-decaborate anion. The regions of electrochemical transformations of the [B10H10](2-) anion for non-aqueous solvents of different structures (acetonitrile, dichloromethane, and tetrahydrofuran) have been studied by the method of cyclic voltammetry. It has been shown that, under the conditions of anodic oxidation, a dimerization product, the [B20H18](2-) anion, is formed. For the synthesis of octadecahydroeicosaborate anion, electrochemical synthesis has been used for the first time.