Bi3+/M2+ oxyphosphate: a continuous series of polycationic species from the 1D single chain to the 2D planes. Part 2: Crystal structure of three original structural types showing a combination of new ribbonlike polycations.
With the assistance of structural models deduced from the high-resolution electron microscope (HREM) investigation presented in Part 1 of this work, three new structural types were pointed out in Bi2O3-MO-P2O5 ternary systems. Their crystal structures are built on the arrangement of 2D polycationic ribbons formed of edge-sharing O(Bi,M)4 tetrahedra and isolated by PO4 groups. Prior to this study, materials with ribbons up to n = 3 tetrahedra wide have been discovered. The original structures presented here display longer n = 4-6 cases, which suggests a possible continuous series of polycationic entities that range from the single chain (one tetrahedron wide) to the infinite [Bi2O2]2+ Aurivillius layer. The ribbons with n > 3 show strong structural modifications that are able to bring a good ribbon-phosphate cohesion. In addition to these fascinating structural results, this work fully confirms the validity of the decoding established from HREM images of a single crystallite in inhomogeneous mixtures.
Colmont
Marie
M
UCCS, équipe de Chimie du Solide, UMR CNRS 8181, ENSC Lille-UST Lille, BP 90108, 59652 Villeneuve d'Ascq Cedex, France.
Huvé
Marielle
M
Mentré
Olivier
O