Spinodal decomposition ranges of wurtzite and zinc blende (ZnBxO1-x)-O-VI (B-VI = S, Se, Te) alloys from 0 degrees C to 1000 degrees C are represented. The strain energy was estimated in the framework of the valence force field model. All considered alloys have the very extensive decomposition zones in spite of the coherency strain energy. Spinodal decomposition in wurtzite alloys should occur in planes with an orientation that depends on the lattice parameters, stiffness coefficients and composition. Zinc blende alloys posses the larger zones and decomposition should take place only in the {100} oriented planes. Spinodal decomposition ranges are 0.02 < x < 0.993, 0.026 < x < 0.994 and 0.045 < x < 0.987 for wurtzite ZnSxO1-x, ZnSexO1-x and ZnTexO1-x, respectively, at RT. (C) 2013 Elsevier B.V. All rights reserved.