In3Ir3B, In3Rh3B and In5Ir9B4, the first indium platinum metal borides

The first indium platinum metal borides have been synthesized and structurally characterized by single crystal X-ray diffraction data. In₃Ir₃B and In₃Rh₃B are isotypic. They crystallize with the hexagonal space group and Z=1. The lattice constants are , for In₃Ir₃B and , for In₃Rh₃B. The structure which is derived from the Fe₂P type is characterized by columns of boron centered triangular platinum metal prisms inserted in a three-dimensional indium matrix. The indium atoms are on split positions. In₅Ir₉B₄ (hexagonal, space group , , , Z=1) crystallizes with a structure derived from the CeCo₃B₂ type. The structure can be interpreted as a layer as well as a channel structure. In part the indium atoms are arranged at the vertices of a honeycomb net (Schlaefli symbol 6³) separating slabs consisting of double layers of triangular Ir₆B prisms, and in part they form a linear chain in a hexagonal channel formed by iridium prisms and indium atoms of the honeycomb lattice.