Undulated oxo-centered layers in PbLn3O4(VO4) (Ln= La and Nd) and relationship with Nd4O4(GeO4)

Publication date: April 2018 Source:Journal of Solid State Chemistry, Volume 260 Author(s): Marie Colmont, Olivier Mentré, Natacha Henry, Alain Pautrat, Bastien Leclercq, Frédéric Capet, Nora Djelal, Pascal Roussel Single crystals of PbLa3O4(VO4) have been synthesized using the flux growth technique and characterized by X-ray diffraction. The crystal structure of the tittle phase was solved by charge flipping and refined to R 1 = 0.024 (wR 2 = 0.031) for 2777 reflections [I>3σ(I)]. The compound is orthorhombic and crystallized in the space group Cmcm: a = 5.8686(6)Å, b = 17.898(2)Å, c = 7.9190(7)Å, V = 831.8(1)Å3, Z = 4. The structure is built on [PbLa3O4]3+ layers with zig-zag cross-sections, surrounded by isolated (VO4)3- tetrahedra. Its crystal structure shows direct relationship with the isoformular Nd4O4(GeO4) compound which crystallized in the primitive non centrosymmetric Pb2 1 m sub-group. Its stability in temperature and under air was checked as well as optical properties. In a second part, lanthanum was substituted by neodymium giving rise to a paramagnet and f→ f electronic excitations superposed to the broad absorption front below 3.05eV related to the presence of VO4 groups. Graphical abstract

Source: Journal of Solid State Chemistry - February 3, 2018 Category: Chemistry Source Type: research