Plumboferrite; new mineralogical data and atomic arrangement

Abstract

Other| October 01, 1995 Plumboferrite: New mineralogical data and atomic arrangement Dan Holtstam; Dan Holtstam Uppsala University, Institute of Earth Sciences, Uppsala, Sweden Search for other works by this author on: GSW Google Scholar Rolf Norrestam; Rolf Norrestam Search for other works by this author on: GSW Google Scholar Arne Sjodin Arne Sjodin Search for other works by this author on: GSW Google Scholar Author and Article Information Dan Holtstam Uppsala University, Institute of Earth Sciences, Uppsala, Sweden Rolf Norrestam Arne Sjodin Publisher: Mineralogical Society of America First Online: 02 Mar 2017 Online ISSN: 1945-3027 Print ISSN: 0003-004X Copyright © 1995 by the Mineralogical Society of America American Mineralogist (1995) 80 (9-10): 1065–1072. https://doi.org/10.2138/am-1995-9-1024 Article history First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Dan Holtstam, Rolf Norrestam, Arne Sjodin; Plumboferrite: New mineralogical data and atomic arrangement. American Mineralogist 1995;; 80 (9-10): 1065–1072. doi: https://doi.org/10.2138/am-1995-9-1024 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyAmerican Mineralogist Search Advanced Search Abstract Plumboferrite from the type locality at Jakobsberg, Filipstad, Sweden, has been reexamined. It occurs in assemblages confined to bands in metamorphic carbonate rock and is associated with hematite, magnesioferrite-jacobsite-magnetite solid solutions, lindqvistite, calcite, andradite, phlogopite, hedyphane, svabite, hematophanite, native copper, and cuprite. Six samples investigated fall in a narrow composition range: PbO 33.9–34.6, Sb2O5 0.0–0.3, Fe2O3 62.4–63.9, MnO 0.6–1.8, TiO2 0.1–0.5, SiO2 0.0–0.2, Al2O3 0.0–0.1, MgO 0.1–0.4 (weight percent). The mineral is moderately anisotropic and optically uniaxial (−). Reflectance values obtained in air are 25.6–24.2% (470 nm), 24.5–23.5% (546 nm), 23.7–22.8 (589 nm), and 22.6–22.1% (650 nm). VHN100 = 882 and Dcalc = 6.12(1) g/cm3.Single-crystal X-ray studies show that plumboferrite is hexagonal, essentially P63/mmc, with the cell dimensions a = 5.931(1), c = 23.551(2) Å, and V = 717.4(2) Å3 (refined from powder data). Overexposed precession X-ray photographs indicate the presence of a supercell with a′=3a=10.27 Å and c′ = 3c = 70.7 Å (hexagonal setting). The structure of plumboferrite has been refined from the 394 most significant (I > 5σI) X-ray reflections with (sin θ)/λ ≤ 0.81 Å−1 to R = 3.9%. It has a defect magnetoplumbite-type structure that can be described in terms of two basic structural units, the R and the S (spinel) blocks. The stacking sequence of such blocks along c is RSR′S′, where ideally R = (Pb2Fe5O11−δ) and S = (Fe6O8) for plumboferrite. The formula (with Z = 2 for the subcell) for the investigated material approaches Pb2Me0.33Fe10.67O18.33, with Me = Mn2+, Mg, rather than PbFe4O7, which is still prevalent in the literature. The departure from stoichiometry (19 O atoms per formula unit) reflects partially occupied 03 positions in the R blocks. The weak superlattice reflections observed (not included in the present refinements) probably result from the ordering of split Pb positions, O vacancies, or both. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.