New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. VIII. Arsenowagnerite, Mg2(AsO4)F | Mineralogical Magazine | Cambridge Core (original) (raw)

Abstract

A new mineral arsenowagnerite, Mg2(AsO4)F, the arsenate analogue of wagnerite, was found in 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 closely with johillerite, tilasite, anhydrite, hematite, fluorophlogopite, cassiterite, calciojohillerite, aphthitalite and fluoborite. Arsenowagnerite occurs as equant to tabular crystals up to 1 mm across combined in interrupted crusts up to 0.1 cm × 1.5 cm × 3 cm. The mineral is transparent, light yellow, lemon-yellow, greenish-yellow or colourless and has a vitreous lustre. Arsenowagnerite is brittle, with Mohs hardness of ~5. Cleavage is distinct, the fracture is uneven. Dcalc = 3.70 g cm–3. Arsenowagnerite is optically biaxial (+), α = 1.614(2), β = 1.615(2), γ = 1.640(2) and 2Vmeas = 25(5)°. Wavenumbers of the strongest absorption bands in the IR spectrum (cm–1) are: 874, 861, 507, 491 and 470. The chemical composition (average of six electron-microprobe analyses, wt.%) is: MgO 38.72, CaO 0.23, MnO 0.32, CuO 0.60, ZnO 0.05, Fe2O3 0.11, TiO2 0.03, SiO2 0.08, P2O5 0.18, V2O5 0.03, As2O5 54.96, SO3 0.10, F 8.91 and –O=F –3.75, total 100.57. The empirical formula calculated on the basis of 5 (O + F) apfu is: (Mg1.98Cu0.02Mn0.01Ca0.01)Σ2.02(As0.99P0.01)Σ1.00O4.03F0.97. Arsenowagnerite is monoclinic, P21/c, a = 9.8638(3), b = 12.9830(3), c = 12.3284(3) Å, β = 109.291(3)°, V = 1490.15(7) Å3 and Z = 16. The strongest reflections of the powder X-ray diffraction pattern [d,Å(I)(hkl)] are: 5.80(41)(002), 5.31(35)(120), 3.916(37)($\bar 2$21), 3.339(98)(221, 023), 3.155(65)(202), 3.043(100)($\bar 1$41), 2.940(72)($\bar 2$04), 2.879(34)($\bar 3$22) and 2.787(51)(320, $\bar 1$24). The crystal structure was solved from single-crystal X-ray diffraction data, R = 0.0485. Arsenowagnerite is isostructural to wagnerite-Ma2bc. The crystal structure is built by almost regular AsO4 tetrahedra, distorted MgO4F2 octahedra and distorted MgO4F trigonal bipyramids.

Type

Article

References

Agilent Technologies (2014) CrysAlisPro Software system, version 1.171.37.34. Agilent Technologies UK Ltd, Oxford, UK.Google Scholar

Anthony, J.W., Bideaux, R.A., Bladh, K.W. and Nichols, M.C. (2000) Handbook of Mineralogy. IV. Arsenates, Phosphates, Vanadates. Mineral Data Publishing, Tucson, USA.Google Scholar

Berrocal, T., Mesa, J.L., Pizarro, J.L., Urtiaga, M.K., Arriortua, M.I. and Rojo, T. (2006) Fe2(AsO4)F: A new three-dimensional condensed fluoro-arsenate iron(II) compound with antiferromagnetic interactions. Journal of Solid State Chemistry, 179, 1659–1667.Google Scholar

Brese, N.E. and O`Keeffe, M. (1991) Bond-valence parameters for solids. Acta Crystallographica B, 47, 192–197.Google Scholar

Chopin, C., Armbruster, T., Grew, E.S., Baronnet, A., Leyx, C. and Medenbach, O. (2014) The triplite–triploidite supergroup: structural modulation in wagnerite, discreditation of magniotriplite, and the new mineral hydroxylwagnerite. European Journal of Mineralogy, 26, 553–565Google Scholar

Clark, R.C. and Reid, J.S. (1995) The analytical calculation of absorption in multifaceted crystals Acta Crystallographica A, 51, 887–897.Google Scholar

Coda, A., Giuseppetti, G., Tadini, C. and Carobbi, S.G. (1967) The crystal structure of wagnerite. Atti della Accademia Nazionale dei Lincei, Classe di Scienze Fisiche, Matematiche e Naturali, 43, 212–224.Google Scholar

Dal Negro, A., Giuseppetti, G. and Pozas, J.M.M. (1974) The crystal structure of sarkinite, Mn2AsO4(OH). Tschermaks Mineralogische und Petrographische Mitteilungen, 21, 246–260.Google Scholar

Engel, G. (1989): Die Kristallstruktur von Cd2AsO4F und ihre Beziehung zu einer Reihe von Oxidsilicaten und Oxidgermanaten der Seltenen Erden. Journal of the Less-Common Metals, 154, 367–374.Google Scholar

Lazic, B., Armbruster, T., Chopin, C., Grew, E.S., Baronnet, A. and Palatinus, L. (2014) Superspace description of wagnerite-group minerals (Mg,Fe,Mn)2(PO4)(F,OH). Acta Crystallographica, B70, 243–258.Google Scholar

Mandarino, J.A. (2007) The Gladstone-Dale compatibility of minerals and its use in selecting mineral species for further study. Canadian Mineralgist, 45, 1307–1324.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.Yu. (2014 a) 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.Google Scholar

Pekov, I.V., Zubkova, N.V., Yapaskurt, V.O., Belakovskiy, D.I., Vigasina, M.F., Sidorov, E.G. and Pushcharovsky, D.Yu. (2014 b) 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, 1527–1543.Google Scholar

Pekov, I.V., Zubkova, N.V., Yapaskurt, V.O., Belakovskiy, D.I., Vigasina, M.F., Sidorov, E.G. and Pushcharovsky, D.Yu. (2015 a) New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. III. Popovite, Cu5O2(AsO4)2. Mineralogical Magazine, 79, 133–143.Google Scholar

Pekov, I.V., Zubkova, N.V., Belakovskiy, D.I., Yapaskurt, V.O., Vigasina, M.F., Sidorov, E.G. and Pushcharovsky, D.Yu. (2015 b) New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. IV. Shchurovskyite, K2CaCu6O2(AsO4)4 and dmisokolovite, K3Cu5AlO2(AsO4)4. Mineralogical Magazine, 79, 1737–1753.Google Scholar

Pekov, I.V., Yapaskurt, V.O., Britvin, S.N., Zubkova, N.V., Vigasina, M.F. and Sidorov, E.G. (2016 a) New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. V. Katiarsite, KTiO(AsO4). Mineralogical Magazine, 80, 639–646.Google Scholar

Pekov, I.V., Zubkova, N.V., Yapaskurt, V.O., Polekhovsky, Yu.S., Vigasina, M.F., Belakovskiy, D.I., Britvin, S.N., Sidorov, E.G. and Pushcharovsky, D.Yu. (2016 b) New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. VI. Melanarsite, K3Cu7Fe3+O4(AsO4)4. Mineralogical Magazine, 80, 855–867.Google Scholar

Pekov, I.V., Yapaskurt, V.O., Belakovskiy, D.I., Vigasina, M.F., Zubkova, N.V. and Sidorov, E.G. (2017) New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. VII. Pharmazincite, KZnAsO4. Mineralogical Magazine, 81, 1001–1008.Google Scholar

Raade, G. and Rømming, C. (1986) The crystal structure of β-Mg2PO4OH, a synthetic hydroxyl analogue of wagnerite. Zeitschrift für Kristallographie, 177, 15–26.Google Scholar

Rea, J.R. and Kostiner, E. (1972) The crystal structure of manganese fluorophosphate, Mn2(PO4)F. Acta Crystallographica, B28, 2525–2529.Google Scholar

Sheldrick, G.M. (2008) A short history of SHELX. Acta Crystallographica, A64, 112–122.Google Scholar

Stock, N., Stucky, G.D. and Cheetham, A.K. (2002) Synthesis and characterization of the synthetic minerals villyaellenite and sarkinite, Mn5(AsO4)2(HAsO4)2·4H2O and Mn2(AsO4)(OH). Zeitschrift für Anorganische und Allgemeine Chemie, 628, 357–362.Google Scholar

Symonds, R.B. and Reed, M.H. (1993) Calculation of multicomponent chemical equilibria in gas-solid-liquid systems: calculation methods, thermochemical data, and applications to studies of high-temperature volcanic gases with examples from Mount St. Helens. American Journal of Science, 293, 758–864.Google Scholar

Waldrop, L. (1969) The crystal structure of triplite, (Mn,Fe)2FPO4. Zeitschrift für Kristallographie, 130, 1–14.Google Scholar