CRYSTAL STRUCTURE OF AgGa2Se3Cl(Br) COMPOUNDS

For the first time, crystal structures of new quaternary compounds were studied by powder method. They crystallize in tetragonal system, Sp.Gr. I-4, structural type CuIn2Te3Cl, with cell parameters: AgGa2Se3Cl (a = 5.9789(3) Å, c 10.8592(7) Å), AgGa2Se3Br 5.9767(3) 10.8558(7) Å). From analysis structure it was found that researched belong to semiconductors general formula AІВІІІ2XVI3YVII (AІ – Cu, Ag; ВІІІ Ga, In; XVI S, Se; YVII  Cl, Br, I). Chalcohalide АІСІІІ2XVI3YVIІ refers cation-defective a ratio cations anions 3:4. Their compositions can be represented Kn-uuAn, where K cations,  vacancies, A anions, u letter word unoccupied. these VEC 4,571. If we consider vacancy as an atom zero valence, get for АІСІІІ2XVI3YVIІ 4. This tetrahedrals when are surrounded four nearest anions. is confirmed AgGa2Se3Cl(Br). The semiconductor properties expected from and other group