New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. III. Popovite, Cu5O2(AsO4)2 | Mineralogical Magazine | Cambridge Core (original) (raw)

Abstract

The new mineral popovite, Cu5O2(AsO4)2, was found in the sublimates of the Arsenatnaya fumarole at the Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia. It is associated with ericlaxmanite, kozyrevskite, urusovite, lammerite, lammerite-β, johillerite, bradaczekite, tenorite, hematite, aphthitalite, anhydrite, langbeinite, calciolangbeinite, As-bearing orthoclase, etc. Popovite occurs as prismatic or tabular crystals and as grains up to 0.2 mm in size forming clusters up to 1.5 mm in size and as crusts on basalt scoria or on aphthitalite incrustations. Popovite is transparent with a vitreous to greasy lustre. Its colour is olive green to dark olive-green, but fine-grained varieties are light yellow-green. The mineral is brittle, with Mohs' hardness ∼3½. Cleavage was not observed and the fracture is uneven. Dcalc is 5.30 g cm–3. Popovite is optically biaxial (+), α = 1.84(1), β ≈ 1.86, γ = 1.96(1), 2Vmeas = 50(20)°. The Raman spectrum is given. Chemical data (wt.%, electron-microprobe) are CuO 63.28, ZnO 0.56, V2O50.12, As2O5 35.80, SO3 0.27, total 100.03. The empirical formula, based on 10 O a.p.f.u., is (Cu4.99Zn0.04)Σ5.03(As1.95S0.02V0.01)Σ1.98O10. Popovite is triclinic, P1̄, a = 5.1450(3), b = 6.2557(3), c = 6.2766(4) Å, α = 100.064(5), β = 96.351(5), γ = 95.100(5)°, V = 196.47(1) Å3 and Z = 1. The strongest reflections in the powder X-ray diffraction pattern [d, Å (I)(hkl)] are 3.715(36)(110, 101), 3.465(43)(11̄1), 2.968(90)(01̄2), 2.927(100)(111), 2.782(31)(1̄02), 2.768(67)(1̄20), 2.513(55)(1̄2̄1) and 2.462(67)(2̄01). Popovite has a novel structure type. Its crystal structure, solved from single-crystal X-ray diffraction data (R = 0.0459), is based on (010) layers forming an interrupted framework. The layer consists of Cu(1)O6 octahedra with very strong Jahn-Teller distortion and Cu(2)O5 and Cu(3)O5 polyhedra. The linkage between the layers is reinforced by isolated AsO4 tetrahedra. Popovite is named in honour of the Russian mineralogists Vladimir Anatol'evich Popov (b. 1941) and Valentina Ivanovna Popova (b. 1941), a husband and wife research team working in the Institute of Mineralogy of the Urals Branch of the Russian Academy of Sciences, Miass, Russia.

Type

Research Article

Copyright

Copyright © The Mineralogical Society of Great Britain and Ireland 2015

References

Birnie, R.W. and Hughes, J.M. (1979) Stoiberite, Cu5V2O10, a new copper vanadate from Izalco volcano, El Salvador, Central America. American Mineralogist 64, 941-944.Google Scholar

Brese, N.E. and O‘Keeffe, M. (1991) Bond-valence parameters for solids. Acta Crystallographica, B47, 192-197.CrossRefGoogle Scholar

Brunel-Lauegt, M. and Guitel, J.C. (1977) Structure cristalline de Cu5O2(PO4)2 . Acta Crystallographica, B33, 3465-3468.CrossRefGoogle Scholar

Krivovichev, S.V. (2009) Structural Crystallography of Inorganic Oxysalts. Oxford University Press, New York.CrossRefGoogle Scholar

Krivovichev, S.V., Shuvalov, R.R., Semenova, T.F. and Filatov, S.K. (1999a) Crystal chemistry of inorganic compounds based on chains of oxocentered tetrahedra. III. The crystal structure of georgbokiite. Zeitschrift für Kristallographie 214, 135-138.Google Scholar

Krivovichev, S.V., Starova, G.L. and Filatov, S.K. (1999b) ‘Face-to-face’ relationships between oxocentred tetrahedra and cation-centred tetrahedral oxyanions in crystal structures of minerals and inorganic compounds. Mineralogical Magazine 63, 263-266.CrossRefGoogle Scholar

Krivovichev, S.V., Filatov, S.K., Burns, P.C. and Vergasova, L.P. (2007) The crystal structure of parageorgbokiite. The Canadian Mineralogist 45, 929-934.CrossRefGoogle Scholar

Pekov, I.V., Zubkova, N.V., Yapaskurt, V.O., Belakovskiy, D.I., Vigasina, M.F., Sidorov, E.G. and Pushcharovsky, D.Y. (2013) Popovite, IMA 2013-060. CNMNC Newsletter No. 17, October 2013, page 3003; Mineralogical Magazine 77, 2997-3005.Google Scholar

Pekov, I.V., Zubkova, N.V., Yapaskurt, V.O., Belakovskiy, D.I., Lykova, I.S., Vigasina, M.F., Sidorov, E.G. and Pushcharovsky, D.Y.. (2014a) New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. I. Yurmarinite, Na7(Fe3+,Mg,Cu)4(AsO4)6. Mineralogical Magazine 78, 905-917.CrossRefGoogle Scholar

Pekov, I.V., Zubkova, N.V., Yapaskurt, V.O., Belakovskiy, D.I., Vigasina, M.F., Sidorov, E.G. and Pushcharovsky, D.Y.. (2014b) New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. II. Ericlaxmanite and kozyrevskite, two natural modifications of Cu4O(AsO4)2 . Mineralogical Magazine 78, 1553-1569.CrossRefGoogle Scholar

Popova, V.I., Popov, V.A., Rudashevskiy, N.S., Glavatskikh, S.F., Polyakov, V.O. and Bushmakin, A.F. (1987) Nabokoite, Cu7TeO4(SO4)5·KCl, and atlasovite, Cu6Fe3+Bi3+O4(SO4)5·KCl, new minerals from volcanic exhalations. Zapiski Vsesoyuznogo Mineralogicheskogo Obshchestva 115, 358-367.Google Scholar

Shannon, R.D. and Calvo, C. (1973) Crystal structure of Cu5V2O10. Acta Crystal lographica, B29, 1338-1345.CrossRefGoogle Scholar

STOE & Cie (2002). WinXPow Software. STOE & Cie GmbH, Darmstadt, Germany.Google Scholar