New Ternary La2Sb-Type Compounds, ScRESb (RE = La, Ce, Pr, Nd, Sm, Tb), and the Oxygen Stuffed Variant Sc4Yb4Sb4O

作者：Nuss Juergen^*; Jansen Martin

来源：Zeitschrift fur Anorganische und Allgemeine Chemie, 2014, 640(5): 713-718.

DOI：10.1002/zaac.201300666

• Rare-earth metals
• Antimonides
• Scandium
• Magnetic properties
• Structure elucidation

Scandium rare-earth metal antimonides, ScRESb (RE = La, Ce, Pr, Nd, Sm, Tb) were synthesized from scandium metal and binary RESb at 1770 K in tantalum ampoules. According to X-ray analyses of the crystal structures, they adopt the tetragonal ScCeSi-type of structure (space group I4/mmm, Pearson code tI12), a variant of La2Sb, with a fully ordered atom distribution. Especially in ScSmSb and ScTbSb, the scandium atoms are distorted from an ideal 4(4) net in a way to form Sc nets of squares and rhombi in order to adjust to the lattice shrinkage in the ab plane, caused by the lanthanide contraction. Finally the structure changes from La2Sb to Sc2Sb-type (anti-PbFCl-type), when terbium is replaced by dysprosium. The respective compound with ytterbium was only found when stoichiometric amounts of oxygen were present, resulting in Sc4Yb4Sb4O, a La2Sb-type variant stuffed with oxygen. A structure field map, based on specific geometric parameters, easily allows for distinguishing between oxygen stuffed and oxygen-free compounds. Magnetic susceptibility measurements of ScCeSb, ScPrSb, and ScNdSb indicate Curie-Weiss behavior with ferromagnetic exchange coupling underlying. The magnetic moments correspond to the expected values for RE3+.

• 出版日期2014-4