SrAu0.5Pt0.5 and CaAu0.5Pt0.5, analogues to the respective Ba compound, but featuring purely intermetallic behaviour

Both, SrAu0.5Pt0.5 and CaAu0.5Pt0.5, have been synthesized by reaction of corresponding mixtures of the pure elements at 1223 K in an argon atmosphere, and characterized by single-crystal X-ray analysis as well as by magnetic susceptibility and electric resistivity measurements. The new compounds crystallize in the CrB type of structure and thus are isostructural to BaAu0.5Pt0.5 (SrAu0.5Pt0.5: Cmcm; a = 4.262(1) Å; b = 11.435(3) Å; c = 4.632(1) Å; Z = 4; CaAu0.5Pt0.5: Cmcm; a = 3.9858(4) Å; b = 10.920(1) Å; c = 4.5249(5) Å; Z = 4). SrAu0.5Pt0.5 as well as CaAu0.5Pt0.5 are poor metallic conductors with ρ300K = 0.95 mΩ.cm and ρ300K = 3.93 mΩ.cm, respectively, and featuring diamagnetic behaviour.According to ESCA measurements SrAu0.5Pt0.5 and CaAu0.5Pt0.5 both can be formulated as having intermetallic character, showing a negligible electron transfer from alkaline earth metals to the noble metals.

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