LaTe(1.9): a tenfold superstructure of the ZrSSi type

Single crystals of LaTe(1.9) (lanthanum telluride) have been obtained by chemical transport reactions with iodine as transport agent. LaTe(1.9) adopts the CeSe(1.9) structure type and crystallizes in the space group P4(2)/n with lattice parameters a = 10.1072 (3) Å and c = 18.2874 (6) Å. The crystal structure comprises an alternating stacking of puckered [LaTe] slabs and planar [Te] layers along [001]. The planar [Te] layer is dominated by dumbbell-shaped Te(2) (2−) anions along an isolated Te(2−) anion and a vacancy. The Te(2) (2−) anions form an eight-membered ring enclosing the vacancy in the centre.