Single crystals of BaLn2Te4 (Ln = Gd-Tm, Y) form as black needles from the stoichiometric reaction BaTe + 2Ln + 3Te at 1000°C. BaSm2Te4 forms as a by-product in the reaction BaTe + Sm+Zn + Te at 850°C with the aid of a BaBr2/KBr flux. The compounds crystallize with four formula units in the space group D2h16-Pnma (No. 62) in the CaFe2O4 (calcium ferrite) structure type. Unit cell constants range from a = 13.6883(10) Å, b = 4.5148(3) Å, and c = 16.3427(12) Å in the Sm compound to a = 13.5677(10) Å, b = 4.4058(3) A, and c = 15.9989(12) Å for Tm (t= -120°C). Ln atoms are coordinated by six Te atoms in an octahedral arrangement. These octahedra share corners and edges to form a three-dimensional channel structure. Ba atoms occupy the bicapped trigonal-prismatic sites within these channels. Magnetic susceptibility data for two representative compounds (Ln = Er and Tb) show paramagnetic behavior in the region 5-300 K. © 2000 Elsevier Science S.A. All rights reserved.