Heterovalent substitution of group IV and V diamagnetic ions in the ferromagnetic spinel CuCr2S4

Heterovalent substitution of As5+, Sb5+, V5+, and Sn4+ diamagnetic ions in CuCr2S4 was studied. The results show that, similar to other 3d10 diamagnetic ions, the As5+ ions occupy only tetrahedral interstices in the close packing of sulfur ions, while the Sb5+ and Sn4+ 4d10 ions, as well as the Sc3+, Ti4+, and V5+ 3d0 ions occupy only octahedral sites. A new compound of composition Cu3AsCr8S16 was synthesized and characterized. It crystallizes in an orthorhombic (sp. gr.Pmm2) spinel-derived structure containing ordered Cu and As ions in tetrahedral sites(a = 13.942 ± 0.004 A,b = 6.878 ± 0.002 A,c = 19.692 ± 0.006 A, Z = 4, V = 1888.43 ± 0.92 A). The CuCr1.5Sb0.5S4 spinel phase is found to crystallize in sp. gr.Fd3m (a = 10.009 ± 0.002 A,u = 0.3815 ± 0.0004 A) with partial ordering on octahedral sites.