The High‐Temperature Modification of GdNiIn 2 ‐ An Intergrowth Structure of MgCuAl 2 ‐Related Slabs

The high‐temperature modification of GdNiIn 2 was prepared by arc‐melting of the elements and subsequent annealing of the sample at 1270 K. Crystals of HT‐GdNiIn 2 were grown with a special annealing program. HT‐GdNiIn 2 was investigated by X‐ray diffraction on powders and single crystals. This indide crystallizes in a new structure type, space group Cmcm , a = 433.4(3), b = 1803(1), c = 2983(2) pm, wR2 = 0.1142, 2306 F 2 values, and 90 variable parameters. All nickel atoms in the HT‐GdNiIn 2 structure have a distorted trigonal prismatic coordination by gadolinium and indium atoms. From a geometrical point of view, the structure of HT‐GdNiIn 2 may be described as an intergrowth of distorted LT‐GdNiIn 2 slabs with MgCuAl 2 structure. The Ni‐In and In‐In contacts have the shortest interatomic distances within the HT‐GdNiIn 2 structure. The nickel and indium atoms form a three‐dimensional [NiIn 2 ] polyanion in which the gadolinium atoms fill distorted pentagonal channels. An initial approximation formula may be written as Gd 3+ [NiIn 2 ] 3‐ therefore.