Redhammer, G.J.; Roth, G.; Tippelt, G.; Bernroider, M.; Lottermoser, W.; Amthauer, G.; Hochleitner, Rupert
Manganoan rockbridgeite Fe4.32Mn0.62Zn 0.06(PO4)3(OH)5: Structure analysis and 57Fe Mössbauer spectroscopy.
In: Acta Crystallographica Section C: Crystal Structure Communications, Vol. 62, No. 3: i24-i28
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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 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 Fe 2+ 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.