A method of computing chemical equilibrium abundances through successive reaction adjustment in its Cruise version is adapted to treat ion and molecular abundances in gaseous system composed of Hydrogen and Helium with minor additives of second row elements. Equilibrium abundances with allowance for ionization have been studied in model atmospheres of cool substellar objects with solar elemental abundances with temperature of photosphere ca. 500—1500 K. Temperature and density dependencies as well as evolutionary trends are considered for abundances of individual species.