  Short range order and topology of Ge$_x$S$_{100-x}$ glasses over a broad
composition range (20 $\le$ x $\le$ 42 in at%) was investigated by neutron
diffraction, X-ray diffraction, and Ge K-edge extended X-ray absorption fine
structure (EXAFS) measurements. The experimental data sets were fitted
simultaneously in the framework of the reverse Monte Carlo simulation method.
It was found that both constituents (Ge and S) satisfy the Mott-rule in all
investigated glasses: Ge and S atoms have 4 and 2 neighbours, respectively. The
structure of these glasses can be described with the chemically ordered network
model: Ge-S bonds are preferred, S-S bonds are present only in S-rich glasses.
Dedicated simulations showed that Ge-Ge bonds are necessary in Ge-rich glasses.
Connections between Ge atoms (such as edge-sharing GeS$_{4/2}$ tetrahedra) in
stoichiometric and S-rich glasses were analysed. The frequency of primitive
rings was also calculated.
