[en] On the basis of experimental and theoretical investigation of chemical equilibrium in the Insub(1-x)Gasub(x)P-HCl system the equilibrium gas phase composition and self-consistent thermodynamic characteristics of the system are calculated. It is shown that along with gallium mono- and trichloride molecules one should take into account gallium dichloride, the presence of which considerably changes the results of the calculation of gas phase equilibrium composition as well as previous notions on possible mechanism of transport and crystallization of gallium binary and ternary compounds with the elements of the 5-th group in the chloride-hydride process