Bismuth flux synthesis and structure of the iridium-rich phosphides RE7Ir 17P 12 ( RE = Y, Gd, Tb, Dy, Ho) with La 7Pd 17P 12 type structure

Abstract

The iridium-rich phosphides RE 7Ir 17P 12 ( RE = Y, Gd, Tb, Dy, Ho) with La 7Pd 17P 12 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 RE 7Ir 17P 12 phosphides belong to the large series of metal-rich compounds with a metal:non-metal ratio of 2:1.