New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. XVIII. Khrenovite, Na3Fe3+2(AsO4)3, the member with the highest sodium in the alluaudite supergroup

Abstract The new alluaudite-group mineral khrenovite with the ideal, end-member formula Na3Fe3+2(AsO4)3 was found in the Arsenatnaya fumarole, Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia. It is associated with aphthitalite-group sulfates, badalovite, calciojohillerite, nickenichite, johillerite, tilasite, svabite, achyrophanite, ozerovaite, pansnerite, arsenatrotitanite, anhydrite, sanidine, hematite, cassiterite, rutile and pseudobrookite. Khrenovite occurs as coarse prismatic crystals up to 0.2 × 0.3 × 0.8 mm and their clusters up to 1 mm across. It is transparent, honey-coloured, red-, orange- or yellow-brown, with vitreous lustre. Khrenovite is brittle, cleavage was not observed. Dcalc is 4.257 g cm–3. Khrenovite is optically biaxial (+), α = 1.825(7), β = 1.834(7), γ = 1.845(7) and 2Vmeas. = 80(10)°. The chemical composition (wt.%, electron-microprobe) is: Na2O 11.47, K2O 1.23, CaO 0.18, MgO 0.01, MnO 4.10, CuO 4.27, ZnO 1.99, Al2O3 0.17, Fe2O3 21.12, SiO2 0.08, P2O5 0.01, V2O5 0.10, As2O5 56.03, SO3 0.02, total 100.78. The empirical formula calculated on the basis of 12 O apfu is (Na2.26K0.16Ca0.02Mn0.35Cu0.33Zn0.15Al0.02Fe3+1.62)Σ4.91(As2.98Si0.01V0.01)Σ3.00O12. Khrenovite is monoclinic, C2/c, a = 12.2394(7), b = 12.7967(5), c = 6.6589(4) Å, β = 112.953(7)°, V = 960.37(10) Å3 and Z = 4. The crystal structure was solved from single-crystal X-ray diffraction data with R1 = 0.0287. Khrenovite is isostructural with other alluaudite-group minerals. Its structural formula simplified to the species-defining constituents is A(1)NaA(2)’NaM(1)NaM(2)Fe3+2(TAsO4)3. The mineral is named in honour of the Russian volcanologist and geologist Anatoly Petrovich Khrenov (1946–2016).

[1]  M. Vigasina,et al.  New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. XVII. Paraberzeliite, NaCaCaMg2(AsO4)3, an alluaudite-group member dimorphous with berzeliite , 2022, Mineralogical Magazine.

[2]  M. Vigasina,et al.  New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. XV. Calciojohillerite, NaCaMgMg2(AsO4)3, a member of the alluaudite group , 2021, Mineralogical Magazine.

[3]  M. Vigasina,et al.  New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. XIV. Badalovite, NaNaMg(MgFe3+)(AsO4)3, a member of the alluaudite group , 2020, Mineralogical Magazine.

[4]  N. Zubkova,et al.  Unusual silicate mineralization in fumarolic sublimates of the Tolbachik volcano, Kamchatka, Russia – Part 1: Neso-, cyclo-, ino- and phyllosilicates , 2020 .

[5]  F. Hatert.  A new nomenclature scheme for the alluaudite supergroup , 2019 .

[6]  M. Vigasina,et al.  New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. XII. Zubkovaite, Ca3Cu3(AsO4)4 , 2019, Mineralogical Magazine.

[7]  S. Britvin,et al.  New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. XI. Anatolyite, Na6(Ca,Na)(Mg,Fe3+)3Al(AsO4)6 , 2019, Mineralogical Magazine.

[8]  N. Zubkova,et al.  Fumarolic arsenates − a special type of arsenic mineralization , 2018, European Journal of Mineralogy.

[9]  N. Chukanov,et al.  New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. VIII. Arsenowagnerite, Mg2(AsO4)F , 2018, Mineralogical Magazine.

[10]  M. Krzhizhanovskaya,et al.  Software for processing the X-ray powder diffraction data obtained from the curved image plate detector of Rigaku RAXIS Rapid II diffractometer , 2017 .

[11]  M. Vigasina,et al.  New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. VI. Melanarsite, K3Cu7Fe3+O4(AsO4)4 , 2016, Mineralogical Magazine.

[12]  F. Hawthorne,et al.  Comprehensive derivation of bond-valence parameters for ion pairs involving oxygen , 2015, Acta crystallographica Section B, Structural science, crystal engineering and materials.

[13]  G. Sheldrick.  Crystal structure refinement with SHELXL , 2015, Acta crystallographica. Section C, Structural chemistry.

[14]  Najoua Ouerfelli,et al.  L'arséniate Na3Fe2(AsO4)3: étude structurale de la forme basse température et simulation des propriétés de conduction des cations alcalins , 2008 .

[15]  P. Keller,et al.  First experimental evidence of alluaudite-like phosphates with high Li-content the (Na1-xLix)MnFe2(PO4)3 series (x = 0 to 1) , 2000 .

[16]  A. Rulmont,et al.  Alluaudite-Like Structure of the Arsenate Na3In2(AsO4)3 , 1997 .

[17]  Jinhua Ye,et al.  Hydrothermal Synthesis and Structures of Na3In2(PO4)3and Na3In2(AsO4)3: Synthetic Modifications of the Mineral Alluaudite , 1997 .

[18]  G. Collin,et al.  Crystal structure, non-stoichiometry and conductivity of II-Na3M2(AsO4)3 (M=Al, Ga, Cr, Fe) , 1988 .

[19]  K. Nakamoto.  Infrared and Raman Spectra of Inorganic and Coordination Compounds , 1978 .