Large-block crystals of AgxCu1-xGaS2 solid solutions were prepared by
a two-temperature procedure followed by directional solidification. Th
e composition variation of lattice parameters was found to obey Vegard
's law. The AgGaS2-CuCaS2 phase diagram was mapped out on the basis of
DTA data. The system is characterized by a narrow temperature range o
f crystallization and can be qualified as the first-type system in Roo
zeboom's classification.