Phases of the Cu-Te-Sb and the Cu-Te-S phase systems.

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    The following is an example of typical studies of Cu-Te-Sb-S Phase systems. If this seems interesting, you are welcome to contact me via email or other wise.

    Experimental studies of the phase systems Cu-Te-Sb and Cu-Te-S at temperatures between 350 and 1000 C have shown the existence of a previously undescribed Cu rich phase. The phase is stable at temperatures between 400 and 900 C. The crystal structure of this phase, Cu9.1TeSb3 was determined from X-ray diffractometer data.

    Tellerium is 12-coordinated by Cu (with 3/4 occupancy) at the distance of 2.614 å. The Cu polyhedron is an icosahedron with four of its ten ideal 3 axes situated in the direction of cubic 3 axes and three of its ideal twofold axes. The copper polyhedron around Sb is a distorted cubooctahedron.
    The crystal structure of Cu9.1TeSb3 is a stuffed derivative of the Cr3Si-structure. The central Te atoms correspond to Si, the Sb icosahedra to those of Cr. The atomic coordinations and the chemical formula of Cu9.1TeSb 3 show that it has character of intermetallic compound.

    For copper coordination the formation of (Cu0.5)12Te clusters appears more important than the accomodation of Cu-Sb distances: The coppper coordination is not a dual (pentagonal dodecahedron) to the enveloping icosahedron.

    The figures show the structure of the described phase and the shape of the mentioned icosahedron.

    Molecular Structure Icosahedron

    DTU KI