[en] Ternary (Ge₂X₃)_x(As₂X₃)_1-x glasses with X = S or Se are of interest because they span a mean coordination number r in the 2.40 < r < 2.8 range that is characteristic of stressed-rigid glasses. We have examined X S glasses in Raman scattering and T-modulated differential scanning calorimetry measurements over the 0 < x < 1.0 range. Glass transition temperatures, T_g(x), increase monotonically in the 0 < x < 0.8 range and decrease thereafter (0.8 < x < 1) to display a global maximum near x = 0.8. Raman scattering provides evidence of sharp modes of As₄S₄ and As₄S₃ monomers, with scattering strength of these modes showing a global maximum near x = 0.3 and 0.5 respectively. The results suggest that at low x (0 < x < 1/2), addition of Ge₂S₃ to the As₂S₃ base glass results in insertion of Ge(S_1/2)₄ tetrahedra in the As(S_1/2)₃-based backbone as compensating As-rich monomers segregate from the backbone to deliver the requisite S. At higher x (0.4 < x < 0.8), the Ge₂S₃ additive continues to enter the glass in a majority (As₂S₃)(GeS₂) backbone and several minority nanophases including an ethane-like Ge₂(S_1/2)₆ and a distorted rock-salt-like GeS. In the 0.8 < x < 1 range, the nanophases grow qualitatively at the expense of the backbone as T_g values decrease and the end-member composition (x = 1) is realized. Heterogeneity of glasses near x = 1/2 or mean coordination, r 2.60 derives intrinsically from the presence of several minority nanophases and a majority backbone showing that stressed-rigid networks usually phase separate on a nanoscale