Formation of complex structural units and structure of some chalco-halide glasses

Raman spectra, thermal expansion and glass transition temperature of (1−x)(CsGaS1.5Cl)−x(0.15Ga2S3 · 0.85GeS2) glasses and evolution of Raman spectra of CsGaS1.5Cl glasses with complete substitution of S by Se and partial substitution of Ga by Al (or In) and of Cl by Br (or I) were studied. The structure of these glasses was discussed considering the ability of A(III) metals to form complex tetrahedral structural units [A(III)B(VI or VII)4]1−, which can be connected by sharing either the common corner of tetrahedra (glasses of (1−x)(CsGaS1.5Cl)−x(0.15Ga2S3 · 0.85GeS2) systems at x>0.1 and CsInS1.5Cl glass) or the common edge of tetrahedra (CsGaS1.5Cl, CsAlS1.5Cl, CsGaSe1.5Cl, CsGaS1.5Br, CsGaS1.5I glasses).