title: Manganoan rockbridgeite Fe4.32Mn0.62Zn0.06(PO4)3(OH)5: structure analysis and 57Fe Mössbauer spectroscopy.
abstract: The structure of the basic iron phosphate rockbridgeite [iron manganese zinc tris(phosphate) pentahydroxide] was reinvestigated with special emphasis on the cation distribution deduced from new X-ray and 57Fe Mössbauer data. Rockbridgeite is orthorhombic, space group Cmcm, and shows three different Fe sites, one with 2/m symmetry, another with m symmetry and the third in a general position. One phosphate group has the P atom on a site with m symmetry, while the other has the P atom at a site with mm symmetry. Two Fe sites are fully occupied by ferric iron, while Mn3+ and Fe2+ are situated at a third, principally Fe, site. Structural data, bond-valence sums and polyhedral distortion parameters suggest a new interpretation of the rockbridgeite 57Fe Mössbauer spectrum.
authors.affiliation: Department of Materials Science, Division of Mineralogy, University of Salzburg, Hellbrunnerstrasse 34, A-5020 Salzburg, Austria. guenther.redhammer@aon.at
authors.forename: Günther J
authors.initials: GJ
authors.lastname: Redhammer
authors.forename: Georg
authors.initials: G
authors.lastname: Roth
authors.forename: Gerold
authors.initials: G
authors.lastname: Tippelt
authors.forename: Manfred
authors.initials: M
authors.lastname: Bernroider
authors.forename: Werner
authors.initials: W
authors.lastname: Lottermoser
authors.forename: Georg
authors.initials: G
authors.lastname: Amthauer
authors.forename: Rupert
authors.initials: R
authors.lastname: Hochleitner