title: Structure determination of phi-Bi8Pb5O17 by electron and powder X-ray diffraction
abstract: The triclinic crystal structure of phi-Bi8Pb5O17, a ionic fast conductor material, has been determined by the synergy of both electron and powder X-ray crystallography. The heavy atom positions were found by direct methods on electron diffraction data and the structure was completed by iterative use of a priori information in direct methods and difference Fourier maps on both types of data. Structure refinement was performed by the Rietveld method on powder X-ray data. The results suggest that phi-Bi8Pb5O17 is an ordered phase, with Bi and Pb atoms occupying different sites of the lattice, at variance with the other structural phases known for similar composition in the Bi-Pb-O phase diagram, which are solid solutions characterised by a wide compositional range.
authors.affiliation: CNR Istituto LAMEL, Area della Ricerca di Bologna, Italy.
authors.initials: M
authors.lastname: Gemmi
authors.initials: L
authors.lastname: Righi
authors.initials: G
authors.lastname: Calestani
authors.initials: A
authors.lastname: Migliori
authors.initials: A
authors.lastname: Speghini
authors.initials: M
authors.lastname: Santarosa
authors.initials: M
authors.lastname: Bettinelli