Crystal Structure and Properties of Some Filled and Unfilled Skutterudites: GdFe4P12, SmFe4P12, NdFe4As12, Eu0.54Co4Sb12, Fe0.5Ni0.5P3, CoP3, and NiP3 |
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Authors: | Wolfgang Jeitschko Aloys J Foecker Dirk Paschke Martin V Dewalsky Ch B H Evers Bernd Künnen Arne Lang Gunter Kotzyba Ute Ch Rodewald Manfred H Mller |
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Abstract: | The new cubic compound Fe0.5Ni0.5P3 (a = 775.29(5) pm) as well as the known compounds CoP3 and NiP3 were synthesized from the elemental components using tin as a flux. Their skutterudite (CoAs3) type structures were refined from single‐crystal X‐ray data. The new compound GdFe4P12 was prepared by reaction of an alloy Gd1/3Fe2/3 with phosphorus in a tin flux. Its cubic “filled” skutterudite (LaFe4P12 type) structure was refined from single‐crystal X‐ray data: a = 779.49(4) pm, R = 0.019 for 304 structure factors and 11 variable parameters. SmFe4P12 shows Van Vleck paramagnetism while GdFe4P12 is a soft ferromagnet with a Curie temperature of TC = 22(5) K. Both are metallic conductors. The new isotypic polyarsenide NdFe4As12 (a = 830.9(1) pm) was obtained by reacting NdAs2 with iron and arsenic in the presence of a NaCl/KCl flux. The new isotypic polyantimonide Eu0.54(1)Co4Sb12 (a = 909.41(8) pm) was prepared by reaction of EuSb2 with cobalt and antimony. Its structure was refined from single‐crystal X‐ray data to a residual of 0.024 (137 F values, 12 variables). A comparison of the Fe–P and P–P bond lengths in the compounds AFe4P12, where the A atoms (A = Ce, Eu, Gd, Th) have differing valencies, suggests that the Fermi level cuts through Fe–P bonding and P–P antibonding bands. |
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Keywords: | Skutterudites Crystal structure Electrical conductivity Magnetic properties Band structure |
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