Synthesis of Ce_2Rh_3Ge_5 Crystals from a Bismuth Flux

摘要

The germanide Ce_2Rh_3Ge_5 was synthesized from the elements in a bismuth flux, and the structure was refined from single-crystal X-ray diffractometer data: U_2Co_3Si_5 type, Ibam, a = 1010.1(2), b = 1210.4(2), c = 599.1(1) pm, wR = 0.0596, 760 structure factors, 31 variables. The rhodium and germanium atoms build up a three-dimensional [Rh_3Ge_5] network (242-269pm Rh-Ge; 300pm Rh-Rh; 266 pm Ge-Ge) in which the cerium atoms fill cavities. Each cerium atom has coordination number 17 by ten germanium (302-331 pm) and seven rhodium (320-355pm) neighbors. The crystal-chemical relation of the Ce_2Rh_3Ge_5 (≡CeRh_(1.5)Ge_(2.5)) structure with that of CeRh_2Ge_2 (ThCr_2Si_2 type) is discussed.