Jakub Plášil

Sejkoraite-(Y), a new member of the zippeite group containing trivalent cations from Jáchymov (St. Joachimsthal), Czech Republic: Description and crystal structure refinement

Abstract Sejkoraite-(Y), the triclinic (Y1.98Dy0.24)Σ2.22H+ 0.34[(UO2)8O88O7OH(SO4)4](OH)(H2O)26, is a new member of the zippeite group from the Červená vein, Jáchymov (Street Joachimsthal) ore district, Western Bohemia, Czech Republic. It grows on altered surface of relics of primary minerals: uraninite, chalcopyrite, and tennantite, and is associated with pseudojohannite, rabejacite, uranopilite, zippeite, and gypsum. Sejkoraite-(Y) forms crystalline aggregates consisting of yellow-orange to orange crystals, rarely up to 1 mm in diameter. The crystals have a strong vitreous luster and a pale yellow-to-yellow streak. The crystals are very brittle with perfect {100} cleavage and uneven fracture. The Mohs hardness is about 2. The mineral is not fluorescent either in short- or long-wavelength UV radiation. Sejkoraite-(Y) is yellow, with no visible pleochroism, biaxial negative with α′ = 1.62(2), β′ = 1.662(3), γ′ = 1.73(1), 2Vcalc = 79°. The empirical chemical formula (mean of 8 electron microprobe point analyses) was calculated on the basis of 12 (S + U) atoms: (Y1.49Dy0.17Gd0.11Er0.07Yb0.05Sm0.02)Σ1.90H+ 0.54 [(UO2)8.19O7OH(SO4)3.81](H2O)26.00. Sejkoraite-(Y) is triclinic, space group P1̄, a = 14.0743(6), b = 17.4174(7), c = 17.7062(8) Å, α = 75.933(4), β = 128.001(5), γ = 74.419(4)°, V = 2777.00(19) Å3, Z = 2, Dcalc = 4.04 g/cm3. The seven strongest reflections in the X-ray powder diffraction pattern are [dobs in Å (I) (hkl)]: 9.28 (100) (100), 4.64 (39) (200), 3.631 (6) (1̄42), 3.451 (13) (1̄44), 3.385 (10) (2̅4̅2), 3.292 (9) (044), 3.904(7) (300), 2.984 (10) (1̄4̅2). The crystal structure of sejkoraite-(Y) has been solved by the charge flipping method from single-crystal X-ray diffraction data and refined to Robs = 0.060 with GOFobs = 2.38, based on 6511 observed reflections. The crystal structure consists of uranyl sulfate sheets of zippeite anion topology, which alternate with an interlayer containing Y3+(H2O)n polyhedra and uncoordinated H2O groups. Two yttrium atoms are linked to the sheet directly via uranyl oxygen atom, and the remaining one is bonded by hydrogen bonds only. In the Raman and infrared spectrum of sejkoraite-(Y) there are dominating stretching vibrations of SO4 tetrahedra (-1200-1100 cm-1), UO22+ stretching vibrations (-900-800 cm-1), and O-H stretching (-3500-3200 cm-1) and H-O-H bending modes (-1640 cm-1). The new mineral is named to honor Jiří Sejkora, a Czech mineralogist of the National Museum in Prague.

Raman spectroscopic study of a hydroxy-arsenate mineral containing bismuth-atelestite Bi2O(OH)(AsO4)

The Raman spectrum of atelestite Bi2O(OH)(AsO4), a hydroxy-arsenate mineral containing bismuth, has been studied in terms of spectra-structure relations. The studied spectrum is compared with the Raman spectrum of atelestite downloaded from the RRUFF database. The sharp intense band at 834 cm(-1) is assigned to the ν1 AsO4(3-) (A1) symmetric stretching mode and the three bands at 767, 782 and 802 cm(-1) to the ν3 AsO4(3-) antisymmetric stretching modes. The bands at 310, 324, 353, 370, 395, 450, 480 and 623 cm(-1) are assigned to the corresponding ν4 and ν2 bending modes and BiOBi (vibration of bridging oxygen) and BiO (vibration of non-bridging oxygen) stretching vibrations. Lattice modes are observed at 172, 199 and 218 cm(-1). A broad low intensity band at 3095 cm(-1) is attributed to the hydrogen bonded OH units in the atelestite structure. A weak band at 1082 cm(-1) is assigned to δ(BiOH) vibration.

Meisserite, Na5(UO2)(SO4)3(SO3OH)(H2O), a new uranyl sulfate mineral from the Blue Lizard mine, San Juan County, Utah, USA

Abstract Meisserite (IMA2013-039), Na5(UO2)(SO4)3(SO3OH)(H2O), is a new uranyl sulfate mineral from the Blue Lizard mine, San Juan County, Utah (USA). It is named in honour of the prominent Swiss mineralogist Nicolas Meisser. The new mineral was found in a sandstone matrix and is associated with chalcanthite, copiapite, ferrinatrite, gypsum, johannite and another new Na-bearing uranyl sulfate, belakovskiite (IMA2013-075). Meisserite is a secondary mineral formed by the post-mining weathering of uraninite. The mineral is triclinic, P1̄, a = 5.32317(10), b = 11.5105(2), c = 13.5562(10) Å, α = 102.864(7)º, β = 97.414(7)º, γ = 91.461(6)º, V = 801.74(6) Å3, and Z = 2. Crystals are prisms elongated on [100], up to 0.3 mm long, exhibiting the forms {010} and {001}. Meisserite is pale green to yellowish green, translucent to transparent and has a very pale yellow streak. It is brittle, with fair cleavage on {100} and {001}, and uneven fracture. The Mohs hardness is estimated at 2. Meisserite is somewhat hygroscopic and easily soluble in water. The calculated density based on the empirical formula is 3.208 g/cm3. Meisserite exhibits bright yellow green fluorescence under both long- and shortwave UV radiation. The mineral is optically biaxial (-), with α = 1.514(1), β = 1.546(1), γ = 1.557(1) (measured in white light). The measured 2V is 60(2)º and the calculated 2V is 60º. Dispersion is r > v, perceptible, and the optical orientation is X≈a, Z≈c*. The mineral is pleochroic, with X (colourless) < Y (pale yellow) ≈ Z (pale greenish yellow). The empirical formula of meisserite (based on 19 O a.p.f.u.) is Na5.05(U0.94O2)(SO4)3[SO2.69(OH)1.31](H2O). The Raman spectrum is dominated by the symmetric stretching vibrations of UO22+, SO42- and also weaker O-H stretching vibrations. The eight strongest powder X-ray diffraction lines are [dobs in Å (hkl) Irel]: 13.15 (001) 81, 6.33 (01̄2) 62, 5.64 (02̅1, 020) 52, 5.24 (100, 012, 1̄01) 100, 4.67 (101) 68, 3.849 (1̄2̅1, 102, 022) 48, 3.614 (03̄2, 1̄1̄3) 41, and 3.293 (1̄13, 004) 43. The crystal structure of meisserite (R1 = 0.018 for 3306 reflections with Iobs > 3σl) is topologically unique among known structures of uranyl minerals and inorganic compounds. It contains uranyl pentagonal bipyramids linked by SO4 groups to form chains. Na+ cations bond to O atoms in the chains and to an SO3OH group and an H2O group between the chains, thereby forming a heteropolyhedral framework.

Adolfpateraite, K(UO2)(SO4)(OH)(H2O), a new uranyl sulphate mineral from Jáchymov, Czech Republic

Abstract Adolfpateraite, monoclinic K(UO2)(SO4)(OH)(H2O), is a new supergene mineral from the Svornost mine, Jáchymov ore district, Czech Republic. It forms sulfur yellow to greenish yellow crystalline aggregates, up to 2 mm in diameter. Crystals are transparent to translucent with a vitreous luster, without observable cleavage. The streak is pale yellow. The Mohs hardness is ~2. The mineral shows a green fluorescence in long-wave ultraviolet radiation. Adolfpateraite is pleochroic, with α = colorless and γ = yellow (β could not been examined). It is biaxial, with α = 1.597(2), γ = 1.659(2) (β could not been measured), birefringence 0.062. The empirical chemical formula (mean of 4 electron microprobe point analyses) was calculated based on 8 O apfu and is K0.94(UO2)1.00(SO4)1.02(OH)0.90(H2O)1.00 (water content calculated). The simplified formula is K(UO2)(SO4)(OH)(H2O), requiring K2O 10.70, UO3 64.97, SO3 18.19, H2O 6.14, total 100.00 wt%. Adolfpateraite is monoclinic, space group P21/c, a = 8.0462(1), b = 7.9256(1), c = 11.3206(2) Å, β = 107.726(2)°, V = 687.65(2) Å3, Z = 4, and Dcalc = 4.24 g/cm3. The five strongest reflections in the X-ray powder diffraction pattern are [dobs in Å (I) (hkl)]: 7.658 (76) (100), 5.386 (100) (002), 5.218 (85) (1̅02), 3.718 (46) (021), 3.700 (37) ( 2̅02). The crystal structure has been refined from single-crystal X-ray diffraction data to R1 = 0.0166 with GOF = 1.30, based on 1915 observed reflections [Iobs > 3σ(I)]. The crystal structure consists of chains of uranyl polyhedra extended along [010], with OH- located on the shared vertex between the bipyramids. The sulfate tetrahedra decorate the outer side of the chain with bridging bidentate linkages between the uranyl pentagonal bipyramids. H2O groups are located on the edges of the chains on the non-linking vertex of each uranyl pentagonal bipyramid. K+ atoms are located between the chains providing additional linkage of these together with H-bonds. The fundamental vibrational modes of uranyl ion, sulfate tetrahedra, and H2O groups were tentatively assigned in the infrared and Raman spectra. The new mineral is named to honor Adolf Patera (1819-1894), Czech chemist, mineralogist, and metallurgist.

A vibrational spectroscopic study of hydrated Fe3+ hydroxyl-sulfates; polymorphic minerals butlerite and parabutlerite

Raman and infrared spectra of two polymorphous minerals with the chemical formula Fe3+(SO4)(OH)·2H2O, monoclinic butlerite and orthorhombic parabutlerite, are studied and the spectra assigned. Observed bands are attributed to the (SO4)2- stretching and bending vibrations, hydrogen bonded water molecules, stretching and bending vibrations of hydroxyl ions, water librational modes, Fe-O and Fe-OH stretching vibrations, Fe-OH bending vibrations and lattice vibrations. The O-H⋯O hydrogen bond lengths in the structures of both minerals are calculated from the wavenumbers of the stretching vibrations. One symmetrically distinct (SO4)2- unit in the structure of butlerite and two symmetrically distinct (SO4)2- units in the structure of parabutlerite are inferred from the Raman and infrared spectra. This conclusion agrees with the published crystal structures of both mineral phases.

Arsenic-rich acid mine water with extreme arsenic concentration: mineralogy, geochemistry, microbiology, and environmental implications.

Extremely arsenic-rich acid mine waters have developed by weathering of native arsenic in a sulfide-poor environment on the 10th level of the Svornost mine in Jáchymov (Czech Republic). Arsenic rapidly oxidizes to arsenolite (As2O3), and there are droplets of liquid on the arsenolite crust with high As concentration (80,000-130,000 mg·L(-1)), pH close to 0, and density of 1.65 g·cm(-1). According to the X-ray absorption spectroscopy on the frozen droplets, most of the arsenic is As(III) and iron is fully oxidized to Fe(III). The EXAFS spectra on the As K edge can be interpreted in terms of arsenic polymerization in the aqueous solution. The secondary mineral that precipitates in the droplets is kaatialaite [Fe(3+)(H2AsO4)3·5H2O]. Other unusual minerals associated with the arsenic lens are běhounekite [U(4+)(SO4)2·4H2O], štěpite [U(4+)(AsO3OH)2·4H2O], vysokýite [U(4+)[AsO2(OH)2]4·4H2O], and an unnamed phase (H3O)(+)2(UO2)2(AsO4)2·nH2O. The extremely low cell densities and low microbial biomass have led to insufficient amounts of DNA for downstream polymerase chain reaction amplification and clone library construction. We were able to isolate microorganisms on oligotrophic media with pH ∼ 1.5 supplemented with up to 30 mM As(III). These microorganisms were adapted to highly oligotrophic conditions which disabled long-term culturing under laboratory conditions. The extreme conditions make this environment unfavorable for intensive microbial colonization, but our first results show that certain microorganisms can adapt even to these harsh conditions.

Mathesiusite, K5(UO2)4(SO4)4(VO5)(H2O)4, a new uranyl vanadate-sulfate from Jáchymov, Czech Republic

Abstract Mathesiusite, K5(UO2)4(SO4)4(VO5)(H2O)4, a new uranyl vanadate-sulfate mineral from Jáchymov, Western Bohemia, Czech Republic, occurs on fractures of gangue associated with adolfpateraite, schoepite, čejkaite, zippeite, gypsum, and a new unnamed K-UO2-SO4 mineral. It is a secondary mineral formed during post-mining processes. Mathesiusite is tetragonal, space group P4/n, with the unit-cell dimensions a = 14.9704(10), c = 6.8170(5) Å, V = 1527.78(18) Å3, and Z = 2. Acicular aggregates of mathesiusite consist of prismatic crystals up to ~200 μm long and several micrometers thick. It is yellowish green with a greenish white streak and vitreous luster. The Mohs hardness is ~2. Mathesiusite is brittle with an uneven fracture and perfect cleavage on {110} and weaker on {001}. The calculated density based on the empirical formula is 4.02 g/cm3. Mathesiusite is colorless in fragments, uniaxial (-), with ω = 1.634(3) and ε = 1.597(3). Electron microprobe analyses (average of 7) provided: K2O 12.42, SO3 18.04, V2O5 4.30, UO3 61.46, H2O 3.90 (structure), total 100.12 (all in wt%). The empirical formula (based on 33 O atoms pfu) is: K4.87(U0.99O2)4(S1.04O4)4(V0.87O5)(H2O)4. The eight strongest powder X-ray diffraction lines are [dobs in Å (hkl) Irel]: 10.64 (110) 76, 7.486 (200) 9, 6.856 (001) 100, 6.237 (101) 85, 4.742 (310) 37, 3.749 (400) 27, 3.296 (401) 9, and 2.9409 (510) 17. The crystal structure of mathesiusite was solved from single-crystal X-ray diffraction data and refined to R1 = 0.0520 for 795 reflections with I > 3σ(I). It contains topologically unique heteropolyhedral sheets based on [(UO2)4(SO4)4(VO5)]5- clusters. These clusters arise from linkages between corner-sharing quartets of uranyl pentagonal bipyramids, which define a square-shaped void at the center that is occupied by V5+ cations. Each pair of uranyl pentagonal bipyramids shares two vertices of SO4 tetrahedra. Each SO4 shares a third vertex with another cluster to form the sheets. The K+ cations are located between the sheets, together with a single H2O group. The corrugated sheets are stacked perpendicular to c. These heteropolyhedral sheets are similar to those in the structures of synthetic uranyl chromates. Raman spectral data are presented confirming the presence of UO22+, SO4, and molecular H2O.

Raman spectroscopic study of the hydroxy-phosphate mineral plumbogummite PbAl3(PO4)2(OH,H2O)6

Plumbogummite PbAl(3)(PO(4))(2)(OH,H(2)O)(6) is a mineral of environmental significance and is a member of the alunite-jarosite supergroup. The molecular structure of the mineral has been investigated by Raman spectroscopy. The spectra of different plumbogummite specimens differ although there are many common features. The Raman spectra prove the spectral profile consisting of overlapping bands and shoulders. Raman bands and shoulders observed at 971, 980, 1002 and 1023 cm(-1) (China sample) and 913, 981, 996 and 1026 cm(-1) (Czech sample) are assigned to the ν(1) symmetric stretching modes of the (PO(4))(3-), at 1002 and 1023 cm(-1) (China) and 996 and 1026 cm(-1) to the ν(1) symmetric stretching vibrations of the (O(3)POH)(2-) units, and those at 1057, 1106 and 1182 (China) and at 1102, 1104 and 1179 cm(-1) (Czech) to the ν(3) (PO(4))(3-) and ν(3) (PO(3)) antisymmetric stretching vibrations. Raman bands and shoulders at 634, 613 and 579 cm(-1) (China) and 611 and 596 cm(-1) (Czech) are attributed to the ν(4) (δ) (PO(4))(3-) bending vibrations and those at 507, 494 and 464 cm(-1) (China) and 505 and 464 cm(-1) (Czech) to the ν(2) (δ) (PO(4))(3-) bending vibrations. The Raman spectrum of the OH stretching region is complex. Raman bands and shoulders are identified at 2824, 3121, 3249, 3372, 3479 and 3602 cm(-1) for plumbogummite from China, and at 3077, 3227, 3362, 3480, 3518 and 3601 cm(-1) for the Czech Republic sample. These bands are assigned to the ν OH stretching modes of water molecules and hydrogen ions. Approximate O-H⋯O hydrogen bond lengths inferred from the Raman spectra vary in the range >3.2-2.62Å (China) and >3.2-2.67Å (Czech). The minority presence of some carbonate ions in the plumbogummite (China sample) is connected with distinctive intensity increasing of the Raman band at 1106 cm(-1), in which may participate the ν(1) (CO(3))(2-) symmetric stretching vibration overlapped with phosphate stretching vibrations.

Manganoblödite, Na2Mn(SO4)2·4H2O, and cobaltoblödite, Na2Co(SO4)2·4H2O: two new members of the blödite group from the Blue Lizard mine, San Juan County, Utah, USA

Abstract Two new minerals - manganoblödite (IMA2012-029), ideally Na2Mn(SO4)2·4H2O, and cobaltoblödite (IMA2012-059), ideally Na2Co(SO4)2·4H2O, the Mn-dominant and Co-dominant analogues of blödite, respectively, were found at the Blue Lizard mine, San Juan County, Utah, USA. They are closely associated with blödite (Mn-Co-Ni-bearing), chalcanthite, gypsum, sideronatrite, johannite, quartz and feldspar. Both new minerals occur as aggregates of anhedral grains up to 60 μm (manganoblödite) and 200 μm (cobaltoblödite) forming thin crusts covering areas up to 2 × 2 cm on the surface of other sulfates. Both new species often occur as intimate intergrowths with each other and also with Mn-Co-Ni-bearing blödite. Manganoblödite and cobaltoblödite are transparent, colourless in single grains and reddish-pink in aggregates and crusts, with a white streak and vitreous lustre. Their Mohs‘ hardness is ~2½. They are brittle, have uneven fracture and no obvious parting or cleavage. The measured and calculated densities are Dmeas = 2.25(2) g cm−3 and Dcalc = 2.338 g cm−3 for manganoblödite and Dmeas = 2.29(2) g cm−3 and Dcalc = 2.347 g cm−3 for cobaltoblödite. Optically both species are biaxial negative. The mean refractive indices are α = 1.493(2), β = 1.498(2) and γ = 1.501(2) for manganoblödite and α = 1.498(2), β = 1.503(2) and γ = 1.505(2) for cobaltoblödite. The chemical composition of manganoblödite (wt.%, electron-microprobe data) is: Na2O 16.94, MgO 3.29, MnO 8.80, CoO 2.96, NiO 1.34, SO3 45.39, H2O (calc.) 20.14, total 98.86. The empirical formula, calculated on the basis of 12 O a.p.f.u., is: Na1.96(Mn0.44Mg0.29Co0.14Ni0.06)Σ0.93S2.03O8·4H2O. The chemical composition of cobaltoblödite (wt.%, electron-microprobe data) is: Na2O 17.00, MgO 3.42, MnO 3.38, CoO 7.52, NiO 2.53, SO3 45.41, H2O (calc.) 20.20, total 99.46. The empirical formula, calculated on the basis of 12 O a.p.f.u., is: Na1.96(Co0.36Mg0.30Mn0.17Ni0.12)Σ 0.95S2.02O8·4H2O. Both minerals are monoclinic, space group P21/a, with a = 11.137(2), b = 8.279(1), c = 5.5381(9) Å, β = 100.42(1)°, V = 502.20(14) Å3 and Z = 2 (manganoblödite); and a = 11.147(1), b = 8.268(1), C = 5.5396(7) Å, β = 100.517(11)°, V = 501.97(10) Å3 and Z = 2 (cobaltoblödite). The strongest diffractions from X-ray powder pattern [listed as (d,Å(I)(hkl)] are for manganoblödite: 4.556(70)(210, 011); 4.266(45)(2̅01); 3.791(26)(2̅11); 3.338(21)(310); 3.291(100)(220, 021), 3.256(67)(211,1̅21), 2.968(22)(2̅21), 2.647(24)(4̅01); for cobaltoblödite: 4.551(80)(210, 011); 4.269(50)(2̅01); 3.795(18)(2̅11); 3.339(43)(310); 3.29(100)(220, 021), 3.258(58)(211, 1̅21), 2.644(21)( 4̅01), 2.296(22)( 1̅22). The crystal structures of both minerals were refined by single-crystal X-ray diffraction to R1 = 0.0459 (manganoblödite) and R1 = 0.0339 (cobaltoblödite).

Crystal structure of pseudojohannite, with a revised formula Cu3(OH)2[(UO2)4O4(SO4)2](H2O)12

Abstract The crystal structure of pseudojohannite from White Canyon, Utah, was solved by charge-flipping from single-crystal X-ray diffraction data and refined to an Robs = 0.0347, based on 2664 observed reflections. Pseudojohannite from White Canyon is triclinic, P1̄, with a = 8.6744(4), b = 8.8692(4), c = 10.0090(5) Å, α = 72.105(4)°, β = 70.544(4)°, γ = 76.035(4)°, and V = 682.61(5) Å3, with Z = 1 and chemical formula Cu3(OH)2[(UO2)4O4(SO4)2](H2O)12. The crystal structure of pseudojohannite is built up from sheets of zippeite topology that do not contain any OH groups; these sheets are identical to those found in zippeites containing Mg2+, Co2+, and Zn2+. The two Cu2+ sites in pseudojohannite are [5]- and [6]-coordinated by H2O molecules and OH groups. The crystal structure of the pseudojohannite holotype specimen from Jáchymov was refined using Rietveld refinement of high-resolution powder diffraction data. Results indicate that the crystal structures of pseudojohannite from White Canyon and Jáchymov are identical.