Bismuth Flux Growth of CeRh₆Ge₄ and CeRh₂Ge₂ Single Crystals

Abstract

Single crystals of the germanides CeRh6Ge4 and CeRh2Ge2 were synthesized from the elements in bismuth fluxes. Polycrystalline samples are available by arc-melting. The structures were refined on the basis of single-crystal X-ray diffractometer data. CeRh 6 Ge 4 : LiCo 6 P 4 type, P 6 m 2 , a=715.4(2), c=385:5(1) pm, wR2=0.0554, 273 F 2 values, 19 variables; CeRh 2 Ge 2 : ThCr 2 Si 2 type, I4/mmm, a=415.69(6), c=1048:5(2) pm, wR2=0.0391, 131 F 2 values, 9 variables. The rhodium and germanium atoms build three-dimensional, covalently bonded [Rh 6 Ge 4 ] and [Rh 2 Ge 2 ] networks with Rh-Ge distances ranging from 246 to 255 pm. The cerium atoms are located in larger cavities within these networks: Ce@Ge 6 Rh 12 in CeRh 6 Ge 4 and Ce@Ge 8 Rh 8 in CeRh 2 Ge 2 . Temperature-dependent magnetic susceptibility data of CeRh6Ge4 show Curie-Weiss behavior above 70 K with an experimental magnetic moment of 2:35(1) μ B per Ce atom. Low-field measurements are indicative of magnetic ordering below 2:5 K.