[en] The results of the study of electrochemical behaviour of titanium, molybdenum, iron and aluminium compounds carried out by the method of cyclic voltammetry and electrolysis with controlled potential are presented. Both molybdenum complexes studied - [Mg(THF)₆][MoOCl₄(THF)₂] and [Mg₂(μ-Cl)₃(THF)₆][MoOCl₄(THF)] are reduced at -0.88 V with transfer of one electron on one molybdenum atom, moreover, Mo(5) -> Mo(4). Magnesium centers do not take part in any redox processes. Mechanism of cathode process has been ascertained by the method of numerical simulation. 18 refs., 5 figs., 4 tabs