The system Cu₃AsS₄–Cu₃SbS₄and investigations on normal tetrahedral structures

Abstract

X-ray diffraction / Powder diffraction structure analysis / Single crystal structure analysis / Thiometallate / Tetrahedral structures / Wurtzite structure type / Sphalerite structure type Abstract. In order to develop a novel model to predict if a so called normal tetrahedral compound crystallizes in a wurtzite-or sphalerite superstructure type, the system Cu 3 AsS 4 --Cu 3 SbS 4 was reinvestigated. A solid solution series was prepared and the mixed crystals were characterized by powder X-ray techniques. [MS 4 ] were calculated for the investigated compounds. In addition, the corresponding data were calculated for further solids from literature data. The volumes of the tetrahedra are used to separate compounds with a sphalerite type anion arrangement from compounds with hexagonal packed anions. A closer inspection of the tetrahedra volumes reveals a greater variation for one given material in the case of wurtzite type superstructures than for sphalerite type superstructures. A critical difference in the tetrahedra volumes is derived from these data.

Research Update: Cu–S based synthetic minerals as efficient thermoelectric materials at medium temperatures

“…1, the crystal structures of the former three are commonly composed of the CuS 4 and (Sb/Sn)S 4 tetrahedral units. [81][82][83] For the SbS 4 configuration, all valence electrons of Sb form covalent bonds with neighboring S atoms, leaving no lone-pair electrons. In Cu 4 SnS 4 , which contains CuS 3 , CuS 4 , and SnS 4 units, the Cu atoms in some sulfur tetrahedra vibrate with a large ADP along the orthorhombic b-axis (Figs.…”

Mixed crystals in the system Cu2MnGexSn1−xS4: Phase analytical investigations and inspection of tetrahedra volumes

“…Therefore we started systematic investigations on tetrahedral compounds of different types [18]. The results underlined the expectations insofar as the tetrahedra distortions in wurtzite superstructure variants were more pronounced than the ones in sphalerite superstructure variants.…”

“…In [18] we presented a concept how to obtain a quantitative measure of this thesis and gave examples.…”

“…The homologous compound Cu 3 PS 4 does not form mixed crystals with Cu 3 SbS 4 and its DV i value (10.3) is much bigger as compared to the As-and Sb-containing solids. [18] Many quaternary tetrahedral compounds crystallize in two polymorphic modifications. The wurtzite modification usually is the high-temperature phase.…”

Synthesis and Characterization of Ag2MnSnS4, a New Diamond‐like Semiconductor

“…This ratio decreases at higher temperatures and therefore describes why wurtzite‐type modifications tend to be more stable at higher temperatures. Further articles have been published which discuss the volumes of tetrahedral compounds and their influence on the structure type …”