CuxAg1-xGaS2 large-scale blocks were obtained by two-temperature synth
esis method with the following crystallization of the melt. It was est
ablished, that crystal lattice parameters are clanged according with V
egard's law, and microhardness have an extremum on the base DTA measur
ements state diagram of AgGaS2-CuGaS2 system was built up. The composi
tion dependence of band gap has nonlinear behaviour.