Bi2O3-CuO-P2O5 system: Two novel compounds built from the intergrowths oxocentered polycationic 1D-ribbons

Single crystals of two novel bismuth copper oxyphosphates were grown from a unique melt They have been structurally characterized by means of single crystal X-Ray Diffraction (XRD). Bi29.4Cu9.29O32(PO4)(16)Cu-2.63 (1) is orthorhombic, space group Pca2(1), a=33.0549(2)angstrom, b=11.6991(4)angstrom and c=5.2902(2)angstrom, R-1=0.059 and wR(2)=0.061. Bi37.2Cu18.8O44(PO4)(24)Cu-5 (2) is orthorhombic, space group Pna2(1), a=11.6010(3)angstrom, b=47.4384(5) angstrom and c=5267(2)angstrom, R-1=0.0940 and wR(2)=0.0981. Both compounds are formed of similar 1D building units (Bus) organized into two different 3D regular intergrowths mediated by phosphate groups. Here, the so-called 1D-BUs are infinite ribbons formed by edge-sharing O(Bi,M)(4) tetrahedra with n=4 and n=3 tetrahedra-wide units. Both compounds were analyzed from the viewpoint of their relationship with the parent delta-Bi2O3 fluorite-like structure, where phosphorus atoms substitutes for some Bi sites. A non-exhaustive review of the related structural types is given. We have checked by second harmonic generacy (SHG) microscopy that the two non-centrosymmetric structures (despite polar subunits) lead to SHG before the samples are irreversibly damaged. (C) 2013 Elsevier Inc. All rights reserved.