Synthesis, structures and magnetic properties of the Eu-based quaternary tellurides EuGdCuTe 3 and EuLuCuTe 3

Novel heterometallic quaternary tellurides EuGdCuTe 3 and EuLuCuTe 3 are reported for the first time. Both compounds were obtained from the elements as single crystals using the flux-assisted synthetic approach. The crystal structure of EuGdCuTe 3 was solved in orthorhombic space group Pnma with the structural type Eu 2 CuS 3 , while the crystal structure of EuLuCuTe 3 belongs to orthorhombic space group Cmcm with the structural type KZrCuS 3 . The 3D crystal structure of EuGdCuTe 3 is constructed from EuTe 7 capped trigonal prisms, GdTe 6 distorted octahedra as well as CuTe 4 tetrahedra. The octahedra form 2D layers, further strengthened by 1D polymeric chains (CuTe 4 ) n . These layers are separated by 1D dimeric ribbons, formed by EuTe 7 capped trigonal prisms and 1D free channels. The 3D crystal structure of EuLuCuTe 3 is constructed from EuTe 6 trigonal prisms, LuTe 6 distorted octahedra and CuTe 4 tetrahedra. The latter two polyhedra also form 2D layers, which are separated by alternating 1D polymeric chains (EuTe 6 ) n and 1D free channels. Both tellurides were found to be paramagnetic with the transition to a ferrimagnetic state at about 8 K for EuGdCuTe 3 and to a ferromagnetic state at about 3 K for EuLuCuTe 3 .