Syntheses, structure, and magnetic properties of several LnYbQ(3) chalcogenides, Q = S, Se

摘要

The six LnYbQ(3) compounds beta-LaYbS3, LaYbSe3, CeYbSe3, PrYbSe3, NdYbSe3, and SmYbSe3 have been synthesized from high-temperature solid-state reactions of the constituent elements at 1223 K. The compounds are isostructural to UFeS3 and crystallize in the space group Cmem of the orthorhombic system with Four formula, units in a cell. Cell constants (Angstrom) at 153 K are: beta-LaYbS3, 3.9238(8), 12.632(3), 9.514(2) LaYbSe3, 4.0616(8), 13.094(3), 9.932(2); CeYbSe3, 4.0234(5), 13.065(2), 9.885(1) PrYbSe3, 4.0152(5), 13.053(2), 9.868(1) NdYbSe3, 4.0015(6), 13.047(2) 9.859(1): SmYbSe3, 3.9780(9), 13.040(3), 9.860(2). The Structure is composed of layers of YbQ(6) (Q = S or Se) octahedra that alternate with layers of LnQ(8) bicapped trigonal prisins along the h-axis. Because there are no Q-Q bonds in the structure the formal oxidation states of Ln/Yb/Q are 3 +/3 + /2-. Magnetic Susceptibility measurements indicate that CeYbSe3 and SmYbSe3 are Curie-Weiss paramagnets over the temperature range 5-300 K. (C) 2003 Elsevier Inc. All rights reserved. [References: 34]