Syntheses and characterization of Ln4Yb11Se22 (Ln = Ce, Sm, Gd)

New interlanthanide selenides Ln4Yb11Se22 (Ln = Ce, Sm, Gd) were synthesized from reactions of their constituent elements at 1123 K. These ordered compounds are isostructural with Ce4Lu11S22, crystallizing with two formula units in the monoclinic space group C2/m. The structure consists of a network of six- and seven-coordinate Yb atoms penetrated by Ln2Se13 infinite chains. Gd4Yb11Se22 has an antiferromagnetic transition at TN = 2.29 K. Gd4Yb11Se22 is a semiconductor with a resistivity of 103 Ω cm at 298 K.