Bismuth flux synthesis and structure of the iridium-rich phosphides RE7Ir17P12 (RE = Y, Gd, Tb, Dy, Ho) with La7Pd17P12 type structure

The iridium-rich phosphides RE7Ir17P12 (RE = Y, Gd, Tb, Dy, Ho) with La7Pd17P12 type structure, space group C2/m were synthesized from the elements in bismuth fluxes. The five structures were refined on the basis of X-ray single crystal diffractometer data. These phosphides have six crystallographically independent phosphorus sites which all have coordination number 9 in tricapped trigonal prismatic metal coordination. These prisms are condensed via common rectangular faces within one layer and via the triangular faces perpendicular to the layers. The second striking structural motif is the broad ranges of Ir–Ir distances within the complex iridium substructure. The RE7Ir17P12 phosphides belong to the large series of metal-rich compounds with a metal:non-metal ratio of 2:1.

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► Synthesis of new metal-rich phosphides RE7Ir17P12.
► Flux-assisted synthesis.
► Structures with trigonal prismatic subunits.