Structural models of (GeS2)(1-x)(P2S5)(x) glasses were developed and used to explain bulk properties of the glasses, including density, glass transition temperature, and refractive index. The models were developed based on combined data from solid-state NMR measurements of spectra and magnetic dipole distributions, neutron diffraction, and Raman spectroscopy. The fundamental structural groups of these glasses consist of GeS4/2 tetrahedra, and both S=PS3/2 and PS3/2 phosphorus units, the latter necessitating also the presence of sulfur-sulfur bonding. Furthermore, the phosphorus sites are present in both network sites and molecular clusters.