Packing on the tetrahedra of sulphur atoms about p-element atoms during the buildings on the AgGaS2, AgGaGeS4 and KGaGeS4 compounds.High-high-quality AgGaGeS4 single crystal has long been correctly developed by the two-zone Bridgman process. Positions of constituent atoms from the device cell in the AgGaGeS4 solitary crystal are already identified.