The variation of the atomic density ϱ with the average coordination number Z for glasses belonging to the Ge_xIn₆Se_94—x and Ge_xIn₁₂Se_88—x families of the Ge–In–Se system is investigated. The ϱ— Z dependence displays broad maxima at Z values of 2.42 and 2.58 for families with 6 and 12 at% In, respectively. These maxima are ascribed to changes from a floppy to a rigid type network and from a two-dimensional layered structure to a three-dimensional network, respectively. The minima exhibited in the ϱ— Z dependence at Z = 2.63 for the In₆ family and at Z = 2.71 for the In₁₂ family, corresponding to the tie-line compositions, are attributed to chemical ordering effects.