Phase homology in new layered mixed Li, M (M=Mg, Cu, Cd, Pb, Bi) bismuth oxophosphates and oxoarsenates

Single crystals of two novel bismuth oxocompounds were grown from melts and the corresponding pure powders obtained from solid state reactions. Both compounds were structurally characterized using X-Ray diffraction techniques. [Bi7O7][BiO]7Cd1Li2(PO4)6 (1) is monoclinic, C2/m, a=26.9234(23), b=5.2926(5), c=12.3024(10) Å, β=106.45(5)°, R1=0.042 and ωR2=0.062. The crystal structure of 1 is related to that of [Bi7O7][BiO]7Bii0.66Li2(PO4)6 and consists of the [Bi7O7]7+ tetrahedral layers with the [(BiO)7CdLi2(PO4)6]7− interlayer blocks, where [BiO]+ denotes units attached to the layers of oxocentered tetrahedra. [Bi4O4][BiO]4Cu1Li2(AsO4)4 (2) is monoclinic, P21/c, a=8.8133(4), b=24.346(1), c=5.4056(2) Å, β=106,93(2)°, R1=0.031 and ωR2=0.035. The crystal structure of 2 is based upon layers similar to those observed in 1, but with the modified topology of the interlayer block. Both compounds can be considered as derivatives from the parent δ-Bi2O3 fluorite-like structure, where phosphorus and arsenic atoms substitute for some Bi sites. The arrangement of the [BiO]+ layers and the XO4 (X=P, As) interlayer groups is significantly modified compared to the previously known Cd compound. The comparison and review of the related structures is given. The variety of aliovalent cations able to incorporate in the interlayer as well as the strong structural resemblance with the Aurivillius series compounds establishes the new routes for the further prospective syntheses of novel but related phases with various important applications.

Two new bismuth oxophosphate compounds were isolated. They both enhance infinite [Bi2O2]2+ layers associated to (BiO)+ dimmers surrounded by interlayer blocks build on XO4 (X=P, As), LiOx and MOy connected entities. Here the insertion of lithium drastically changed the classical topology observed in related Aurivillius compounds.Figure optionsDownload as PowerPoint slideHighlights
► Two new bismuth oxophosphate were synthesized.
► Crystal structure were solved thanks to single crystal X-Ray diffraction.
► They show infinite [Bi2O2]2+ layers surrounded by XO4 (X=P, As), LiOx and MOy connected entities.
► The insertion of lithium drastically changed the classical topology observed in related Aurivillius compounds.