Synthesis and Structure of RhMg3 and Ir3Mg13

Viktor Hlukhyy, Ute Ch. Rodewald, Rolf-Dieter Hoffmann, Rainer Pöttgen
2004 Zeitschrift für Naturforschung. B, A journal of chemical sciences  
The binary transition metal magnesium compounds RhMg3 and Ir3Mg13 have been synthesized from the elements in sealed niobium tubes and investigated on the basis of X-ray powder and single crystal data: Cu3P type, P63cm, a = 790.5(4), c = 825.6(3) pm, wR2 = 0.0244, 344 F2 values, 27 variable parameters for RhMg3, and R3̅c, a = 1607.0(2), c = 844.88(9) pm, wR2 = 0.0535, 656 F2 values, 29 variable parameters for Ir3Mg13. The rhodium atoms in RhMg3 have coordination number 11. These polyhedra show
more » ... se polyhedra show an AB AB stacking sequence like in the hexagonal close-packed structure. The crystal chemical relation of the Cu3P type structure of RhMg3 with the aristotype Na3As (IrAl3) is discussed on the basis of a group-subgroup scheme. Ir3Mg13 crystallizes with a new complex structure type with coordination numbers of 11, 14, 15, 14, and 12 for the Ir, Mg1, Mg2, Mg3, and Mg4 atoms, respectively
doi:10.1515/znb-2004-0301 fatcat:gzw5mimv6vdujmaoqbr2bkb64y