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A new barium uranyl oxide hydrate mineral, protasite

Published online by Cambridge University Press:  05 July 2018

M. K. Pagoaga ,
D. E. Appleman  and
J. M. Stewart
M. K. Pagoaga
Affiliation:
Chemistry Department, University of Maryland, College Park, Maryland 20742, USA
D. E. Appleman
Affiliation:
Museum of Natural History, Smithsonian Institution, Washington, DC 20560, USA
J. M. Stewart
Affiliation:
Chemistry Department, University of Maryland, College Park, Maryland 20742, USA
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Abstract

Protasite, a new barium-containing member of the uranyl oxide hydrate group, occurs as bright orange pseudo-hexagonal platelets associated with uraninite and uranophane on unidentified rock matrix from Shinkolobwe mine, Zaïre. Protasite is monoclinic, Pn with a 12.295(2), b 7.221(1), c 6.9558(8) Å, β 90.40(2)°, and V 617.50(11) Å3. The tabular pseudo-hexagonal crystals are flattened on {010}, 0.1 mm to 0.5 mm wide and up to 0.1 mm thick. They are biaxial negative, 2 V = 60–65°, β and γ 1.79–1.83, and X = b. Sector twinning is common. Microprobe analysis shows BaO 15.0, UO3 78.0, H2O(diff.) 7.0%. The structural formula is Ba[(UO2)3O3(OH)2]. 3H2O, Z = 2, and density(calc.) = 5.827(3) g cm−3. Complete crystal-structure analysis shows protasite to be the simplest model structure of the uranyl oxide hydrate group.

Keywords

protasitenew mineraluranyl oxideShinkolobwe mineZaïre
Type
Mineralogy
Information
Mineralogical Magazine , Volume 50 , Issue 355 , March 1986 , pp. 125 - 128
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1986

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References

Appleman, D.E., and Evans, H.T., Jr. (1973) Indexing and Least-Squares Refinement of Powder Diffraction Data. Geological Survey Computer Contribution, USGSGD- 73-003, US Geological Survey, Washington DC, 62 pp.Google Scholar
Brown, I.D., and Wu, K.K. (1976) Empirical Parameters for Calculating Cation-Oxygen Bond Valences. Ada Crystallogr. B32, 1957.CrossRefGoogle Scholar
Christ, C.L., and Clark, J.R. (1960) Crystal Chemical Studies of Some Uranyl Oxide Hydrates. Am. Mineral. 45, 1026.Google Scholar
Colby, J.W. (modified by L. W. Finger) (1975) Magic IV—A Computer Program for Quantitative Electron Microprobe Analysis.Allentown, PA: Bell Telephone Laboratories, Inc.Google Scholar
Evans, H.T., Jr. (1963) Uranyl Ion Coordination. Science, 141, 154.CrossRefGoogle Scholar
Ibers, J.A., and Hamilton, W.C. eds. (1974) International Tables for X-ray Crystallography, 4. Birmingham, England: Kynoch Press.Google Scholar
Jarosewich, E., Nelen, J.A., and Norberg, J.A. (1980) Reference Samples for Electron Microprobe Analysis. Geostandards Newsletter. 4, 43.CrossRefGoogle Scholar
Loopstra, B.O. (1964) Neutron Diffraction Investigation of U3O8. Acta Crystallogr. 17, 651.CrossRefGoogle Scholar
Loopstra, B.O. (1970) The structure of beta-U3O8. Ibid. B26, 656.Google Scholar
Mandarino, J.A. (1979) The Gladstone-Dale Relationship. Part III: Some General Applications. Can. Mineral. 17, 71.Google Scholar
Pagoaga, M.K. (1983) The Crystal Chemistry of the Uranyl Oxide Hydrate Minerals.Chemistry Department, University of Maryland, College Park, Maryland, 167 pp.Google Scholar
Piret-Meunier, J., and Piret, P. (1982) Nouvelle determination de la structure cristalline de la becquerelite. Bull. Minéral. 105, 606.CrossRefGoogle Scholar
Protas, J. (1959) Contribution á l'étude des oxides d'uranium hydrates. Bull. Soc.fr. Minéral. Cristallogr. 82, 239.CrossRefGoogle Scholar
Rogova, V.P., Belova, L.N., Kiziyarov, G.N. and Kuznetsova, N.N. (1974) Bauranoite and Metacalciouranoite, New Minerals of the Hydrous Uranium Oxides Group. Intern. Geol. Rev.(English translation) 16, 214.Google Scholar
Stewart, J.M. et al.(1976) The X-ray System ofCrystallographic Programs. TR-446, Computer Science Center, Univ. of Maryland, College Park, Maryland, 232 pp.Google Scholar
Stewart, J.M. et al.(1983) The XTAL83 System of Crystallographic Programs: USER's MANUALTR-1364, Computer Science Center, Univ. of Maryland, College Park, Maryland, 244 pp.Google Scholar