[en] Using the methods of electron, IR and ESR spectroscopy both by means of preparation and potentiometric titration, interaction of tungsten (5) with dithiols (H₂R-quinoxaline-2,3-dithiol; 3,4-dimercaptotoluene) in the presence of different acidoligands (chloride- and mercaptide ions) in non-aqueous media (Solv-dimethyl formamide, pyridine, hexamethyl triaminophosphate, acetonitrile) is investigated. Composition and formation conditions of the complexes WOCl₃RH₂⁰, WOCl₃RH^-, WOCl₂RSolv^-, WOClSolvRSolv⁰, WaR₂Solv^-, WOR(RH)₂^-, WR₃^- are determined. It is established that parameters of spin-Hamiltonian of tungsten (5) complexes with thio-and selenium-containing ligands depend considerably on the charge of donor atom. Synthesis of WR₃⁰ is carried out, its properties being investigated. A diagram of tungsten (5) distribution between paramagnetic forms depending forms depending on pH is calculated