Structure D 2000 Luminescent Lanthanide Selenites and Tellurites Decorated by MoO 4 Tetrahedra or MoO6 Octahedra: Nd2MoSe2O10, Gd2MoSe3O12, La2MoTe3O12, and Nd2MoTe3O12. -Solid state reactions of Ln2O3 (Ln: Nd, Gd, La), MoO3, and SeO2 or TeO2 (evacuated quartz tube, 700-750°C, 6-7 d) lead to the four new quaternary title phases with four different types of structures. The structure of Nd2MoSe2O10 (triclinic, space group P1, Z = 2) features a three-dimensional architecture characterized by an intergrowth of Nd-Se-O and Nd-Mo-O layers. The structure of Gd2MoSe3O12 (triclinic, P1, Z = 2) consists a three-dimensional network of gadolinium selenite with cavities occupied by MoO6 octahedra. La2MoTe3O12 (orthorhombic, Pnma, Z = 4) exhibits a three-dimensional [La2(Te3O8) 2+ ] network with tunnels occupied by MoO4 tetrahedra. Nd 2 MoTe 3 O 12 (orthorhombic, Pnma, Z = 4) contains layers built by the Nd 3+ ions interconnected by tellurite and ditellurite groups, with the MoO4 tetrahedra as the interlayer pendant groups. Room temperature and low temperature luminescent studies indicate that the two Nd compounds exhibit strong luminescence in the near-IR region. -(SHEN, Y.-L.; JIANG, H.-L.; XU, J.; MAO*, J.-G.; CHEAH, K. W.; Inorg. Chem. 44 (2005) 25, 9314-9321; State Key Lab. Struct. Chem., Fujian Inst. Res. Struct. Matter, Chin. Acad. Sci., Fuzhou 350002, Peop. Rep. China; Eng.) -Schramke 09-008