Zwei metallreiche Phosphide – Die Kristallstrukturen von Mg 8 Ir 23 P 8 und Mg 13 Pt 26 P 10

Two Metal‐rich Phosphides – The Crystal Structures of Mg 8 Ir 23 P 8 and Mg 13 Pt 26 P 10 Mg 8 Ir 23 P 8 ( a = 8.586(4), b = 16.998(7), c = 3.959(2) Å) and Mg 13 Pt 26 P 10 ( a = 8.834(2), b = 21.154(4), c = 4.074(1) Å) crystallize in new structure types ( Pbam , Z = 1), which were determined by single crystal methods. In the Ir compound four of seven crystallographically different Ir atoms build up cuboctahedra centered by other Ir atoms. The cuboctahedra are connected with each other via common faces to strands along [001] and they are linked with Ir 5 square pyramids centered by P atoms to a three‐dimensional network, in which some of the Ir atoms are part of both polyhedra. The Mg atoms are situated in the holes of the network coordinated by 14 nearest neighbours. The structure of Mg 13 Pt 26 P 10 is quite similar and contains cuboctahedra too, but they are formed by both kinds of metal atoms building two different polyhedra. The first type is centered by Pt atoms, whereas the centers of the other one are occupied by Mg atoms and P 2 dumb‐bells with a statistical distribution. The cuboctahedra are linked with each other via common faces along [001] and edges along [100] and they are connected with Pt 5 square pyramids centered by P atoms in a similar fashion like in Mg 8 Ir 23 P 8 .