Abstract Topological analysis of atomic nets in the crystal structures of 284 anhydrous inorganic salts M_y(TO₄)_z (T = Si, Ge, P, As, S, Se, Cl, Br, I) containing isolated orthogroups TO₄ was performed by means of the program package TOPOS 3.2. The topological relations were found among the M_y(TO₄)_z salts and 1164 topological types of the binary compounds A_yX_z at the two levels: grey isomorphism and partial isotypism. Using the method of coordination sequences nearly a half (47.5%) of the ortho structures in the quasi-binary representation M_y[T]_z were found to match 27 frequent topological types of the binary compounds (NaCl, NiAs, FeB, α-Al₂O₃, etc.). The model of cation arrays was shown to sometimes disagree with the model of atomic nets while comparing; the reasons of such disagreements were discussed.