Dokuchaevite, Cu8O2(VO4)3Cl3, a new mineral with remarkably diverse Cu2+ mixed-ligand coordination environments

2019 ◽  
Vol 83 (5) ◽  
pp. 749-755 ◽  
Author(s):  
Oleg I. Siidra ◽  
Evgeny V. Nazarchuk ◽  
Anatoly N. Zaitsev ◽  
Yury S. Polekhovsky ◽  
Thomas Wenzel ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Three Dimensional ◽  
Kamchatka Peninsula ◽  
Structural Formula ◽  
Scoria Cone ◽  
Structure Type ◽  
Mixed Ligand ◽  
New Mineral ◽  
The North ◽  
Ligand Coordination

AbstractDokuchaevite, ideally Cu8O2(VO4)3Cl3, was found in the Yadovitaya fumarole of the Second scoria cone of the North Breach of the Great Tolbachik Fissure Eruption (1975–1976), Tolbachik volcano, Kamchatka Peninsula, Russia. Dokuchaevite occurs on the crusts of various copper sulfate exhalative minerals (such as kamchatkite and euchlorine) as individual prismatic crystals. Dokuchaevite is triclinic, P$\bar{1}$, a = 6.332(3), b = 8.204(4), c = 15.562(8) Å, α = 90.498(8), β = 97.173(7), γ = 90.896(13)°, V = 801.9(7) Å3 and R1 = 0.057. The eight strongest lines of the X-ray powder diffraction pattern are (d, Å (I)(hkl): (15.4396)(18)(00$\bar{1}$), (7.2762)(27)(0$\bar{1}$1), (5.5957)(43)(012), (4.8571)(33)($\bar{1}\bar{1}$1), (3.1929) (29)(023), (2.7915)(30)(202), (2.5645)(21)(032), (2.5220)(100)(1$\bar{3}$0), (2.4906)(18)(130) and (2.3267)(71)(2$\bar{2}$2). The chemical composition determined by electron-microprobe analysis is (wt.%): CuO 60.87, ZnO 0.50, FeO 0.36, V2O5 19.85, As2O5 6.96, SO3 0.44, MoO3 1.41, SiO2 0.20, P2O5 0.22, Cl 10.66, –O = Cl2 2.41, total 99.06. The empirical formula calculated on the basis of 17 anions per formula unit is (Cu7.72Zn0.06Fe0.05)Σ7.83(V2.20As0.61Mo0.10S0.06P0.03Si0.03)Σ3.03O13.96Cl3.04.The crystal structure of dokuchaevite represents a new structure type with eight Cu sites, which demonstrate the remarkable diversity of Cu2+ mixed-ligand coordination environments. The crystal structure of dokuchaevite is based on OCu4 tetrahedra that share common corners thus forming [O2Cu6]8+ single chains. Two of the eight symmetrically independent copper atoms do not form Cu–O bonds with additional oxygen atoms, and thus are not part of the OCu4 tetrahedra, but provide the three-dimensional integrity of the [O2Cu6]8+ chains into a framework. TO4 mixed tetrahedral groups are located within the cavities of the framework. The structural formula of dokuchaevite can be represented as Cu2[Cu6O2](VO4)3Cl3.

Majzlanite, K2Na(ZnNa)Ca(SO4)4, a new anhydrous sulfate mineral with complex cation substitutions from Tolbachik volcano

2019 ◽  
Vol 84 (1) ◽  
pp. 153-158 ◽  
Author(s):  
Oleg I. Siidra ◽  
Evgeny V. Nazarchuk ◽  
Anatoly N. Zaitsev ◽  
Vladimir V. Shilovskikh
Keyword(s):  
Complex Cation ◽  
Kamchatka Peninsula ◽  
Structural Formula ◽  
Scoria Cone ◽  
New Mineral ◽  
X Ray ◽  
Mineral Assemblages ◽  
Tolbachik Volcano ◽  
Cation Substitutions ◽  
Heteropolyhedral Framework

AbstractA new mineral majzlanite, ideally K2Na(ZnNa)Ca(SO4)4, was found in high-temperature exhalative mineral assemblages in the Yadovitaya fumarole, Second scoria cone of the Great Tolbachik Fissure Eruption (1975–1976), Tolbachik volcano, Kamchatka Peninsula, Russia. Majzlanite is associated closely with langbeinite and K-bearing thénardite. Majzlanite is grey with a bluish tint, has a white streak and vitreous lustre. The mineral is soluble in warm water. Majzlanite is monoclinic, C2/c, a = 16.007(2), b = 9.5239(11), c = 9.1182(10) Å, β = 94.828(7)°, V = 1385.2(3) Å3 and Z = 16. The eight strongest lines of the X-ray powder diffraction pattern are [d, Å (I, %)(hkl)]: 3.3721(40)($\bar{3}$12), 3.1473(56)($\bar{4}$02), 3.1062(65)($\bar{2}$22), 2.9495(50)($\bar{1}$31), 2.8736(100)($\bar{1}$13), 2.8350(70)(421), 2.8031(45)(511) and 2.6162(41)($\bar{5}$12). The following structural formula was obtained: K2Na(Zn0.88Na0.60Cu0.36Mg0.16)(Ca0.76Na0.24)(S0.98Al0.015Si0.005O4)4. The chemical composition determined by electron-microprobe analysis is (wt.%): Na2O 9.73, K2O 15.27, ZnO 11.20, CaO 7.03, CuO 4.26, MgO 1.07, Al2O3 0.47, SO3 51.34, SiO2 0.12, total 100.49. The empirical formula calculated on the basis of 16 O apfu is K1.99Na1.93Zn0.84Ca0.77Cu0.33Mg0.16(S3.94Al0.06Si0.01)O16 and the simplified formula is K2Na(Zn,Na,Cu,Mg)Σ2(Ca,Na)(SO4)4. No natural or synthetic compounds directly chemically and/or structurally related to majzlanite are known to date. The topology of the heteropolyhedral framework in majzlanite is complex. An interesting feature of the structure of majzlanite is an edge-sharing of ZnO6 octahedra with SO4 tetrahedra.

scholarly journals A New Mineral Ferrisanidine, K[Fe3+Si3O8], the First Natural Feldspar with Species-Defining Iron

Minerals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 770 ◽  
Author(s):  
Nadezhda Shchipalkina ◽  
Igor Pekov ◽  
Sergey Britvin ◽  
Natalia Koshlyakova ◽  
Marina Vigasina ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Chemical Composition ◽  
Electron Microprobe ◽  
Empirical Formula ◽  
Rietveld Method ◽  
Kamchatka Peninsula ◽  
Scoria Cone ◽  
Unit Cell ◽  
New Mineral ◽  
Tolbachik Volcano

Ferrisanidine, K[Fe3+Si3O8], the first natural feldspar with species-defining iron, is an analogue of sanidine bearing Fe3+ instead of Al. It was found in exhalations of the active Arsenatnaya fumarole at the Second scoria cone of the Northern Breakthrough of the Great Fissure Tolbachik Eruption, Tolbachik volcano, Kamchatka Peninsula, Russia. The associated minerals are aegirine, cassiterite, hematite, sylvite, halite, johillerite, arsmirandite, axelite, aphthitalite. Ferrisanidine forms porous crusts composed by cavernous short prismatic crystals or irregular grains up to 10 μm × 20 μm. Ferrisanidine is transparent, colorless to white, the lustre is vitreous. Dcalc is 2.722 g·cm−3. The chemical composition of ferrisanidine (wt. %, electron microprobe) is: Na2O 0.25, K2O 15.15, Al2O3 0.27, Fe2O3 24.92, SiO2 60.50, in total 101.09. The empirical formula calculated based on 8 O apfu is (K0.97Na0.03)Ʃ1.00(Si3.03Fe3+0.94Al0.02)Ʃ3.99O8. The crystal structure of ferrisanidine was studied using the Rietveld method, the final R indices are: Rp = 0.0053, Rwp = 0.0075, R1 = 0.0536. Parameters of the monoclinic unit cell are: a = 8.678(4), b = 13.144(8), c = 7.337(5) Å, β = 116.39(8)°, V = 749.6(9) Å3. Space group is C2/m. The crystal structure of ferrisanidine is based on the sanidine-type “ferrisilicate” framework formed by disordered [SiO4] and [Fe3+O4] tetrahedra.

Belousovite, KZn(SO4)Cl, a new sulfate mineral from the Tolbachik volcano with apophyllite sheet-topology.

2018 ◽  
Vol 82 (5) ◽  
pp. 1079-1088 ◽  
Author(s):  
Oleg I. Siidra ◽  
Evgeny V. Nazarchuk ◽  
Evgeniya A. Lukina ◽  
Anatoly N. Zaitsev ◽  
Vladimir V. Shilovskikh
Keyword(s):  
Inorganic Compounds ◽  
Direct Methods ◽  
Kamchatka Peninsula ◽  
Scoria Cone ◽  
Mixed Ligand ◽  
X Ray Diffraction ◽  
Coordination Polyhedra ◽  
The North ◽  
Tolbachik Volcano ◽  
Group A

ABSTRACTBelousovite, ideally KZn(SO4)Cl, was found in a Yadovitaya fumarole of the Second scoria cone of the North Breach of the Great Tolbachik Fissure Eruption (1975–1976), Tolbachik volcano, Kamchatka Peninsula, Russia. Belousovite occurs as irregularly-shaped grains and in the form of microcrystalline masses associated with kamchatkite, langbeinite, euchlorine, anglesite and zincite. Belousovite is monoclinic, P21/c, a = 6.8904(5), b = 9.6115(7), c = 8.2144(6) Å, β = 96.582(2), V = 540.43(7) Å3 and Z = 4 (from single-crystal diffraction data). The eight strongest lines of the powder X-ray diffraction pattern are [dmeas Å(I)(hkl)]: 6.8451(100)(100), (3.6401)(71)($\bar{1}$21), (3.1592)(84)(1$\bar{1}$2), (3.1218)(41)($\bar{2}$11), (3.1140)(52)(022), (2.9812)(41)(031), (2.9121)(44)(130) and (2.0483)(19)($\bar{3}$12). The chemical composition determined by the electron-microprobe analysis is (wt.%): K2O 19.55, Rb2O 0.58, ZnO 34.85, SO3 34.65, Cl 14.77, –O = Cl2 3.34, total 101.06. The empirical formula based on O + Cl = 5 apfu is K0.97Rb0.01Zn1.00S1.01O4.03Cl0.97. The simplified formula is KZn(SO4)Cl. The crystal structure was solved by direct methods and refined to R1 = 0.029 on the basis of 1965 independent observed reflections. The structure of belousovite consists of infinite [ZnSO4Cl]– layers and K+ ions. [ZnSO4Cl]– layers are formed by corner sharing mixed-ligand ZnO3Cl tetrahedra and SO4 tetrahedra. The topology of [ZnSO4Cl]– layers in belousovite is identical to [Si4O10]4– layers in the minerals of the apophyllite group. A review of mixed-ligand ZnOmCln coordination polyhedra in minerals and inorganic compounds is given.

Unique thallium mineralization in the fumaroles of the Tolbachik volcano, Kamchatka Peninsula, Russia. II. Karpovite, Tl2VO(SO4)2(H2O)

2014 ◽  
Vol 78 (7) ◽  
pp. 1699-1709 ◽  
Author(s):  
Oleg I. Siidra ◽  
Lidiya P. Vergasova ◽  
Yuri L. Kretser ◽  
Yuri S. Polekhovsky ◽  
Stanislav K. Filatov ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Cinder Cone ◽  
Direct Methods ◽  
Kamchatka Peninsula ◽  
Dimensional Structure ◽  
New Mineral ◽  
The North ◽  
Tolbachik Volcano ◽  
Oriented Parallel ◽  
Academy Of Sciences

AbstractKarpovite, ideally Tl2VO(SO4)2(H2O), was found in a fumarole of the 1st cinder cone of the North Breach of the Great Fissure Tolbachik volcano eruption (1975–1976), Kamchatka Peninsula, Russia. Karpovite occurs as bundles of white, needle-like crystals associated with shcherbinaite, pauflerite, bobjonesite, markhininite, evdokimovite and microcrystalline Mg, Al, Fe and Na sulfates. Karpovite is monoclinic, P21, a = 4.6524(4), b = 11.0757(9), c = 9.3876(7) Å , β = 98.353(2)º, V = 478.60(7) Å3, Z = 2 (from single-crystal diffraction data). The eight strongest lines of the X-ray powder diffraction pattern are (I/d/hkl): 64/4.289/012, 81/4.253/110, 38/3.683/111, 47/3.557/022, 100/3.438/1̄21, 52/2.982/013, 59/2.945/112, 54/2.354/132. The chemical composition determined by the electron microprobe analysis is (wt.%) Tl2O 61.43, VO2 11.53, SO3 23.55, H2O 2.61, total 99.12. The empirical formula (calculated on the basis of 10 O a.p.f.u.) is Tl2.00V0.96S2.03O9(H2O). The simplified formula of karpovite is Tl2VO(SO4)2(H2O), which requires Tl2O 61.93, VO2 12.09, SO3 23.34, H2O 2.62 total 100.00 wt.%. The crystal structure was solved by direct methods and refined to R1 = 0.026 for 4196 independent observed reflections. The structure contains two symmetrically independent Tl+ sites, one V4+ site and two S6+ sites. VO5H2O octahedra and SO4 tetrahedra link together by sharing corners to form kröhnkite-type stripes parallel to the a axis with their planes oriented parallel to (021) and (021̄ ). Tl+ cations are located between the chains, linked into a three-dimensional structure. The new mineral is named in honour of Professor Gennadii Alexandrovich Karpov (b. 1938), volcanologist at the Institute of Volcanology, Russian Academy of Sciences, Petropavlovsk-Kamchatskii, Kamchatka Peninsula, Russia.

New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. VI. Melanarsite, K3Cu7Fe3+O4(AsO4)4

2016 ◽  
Vol 80 (5) ◽  
pp. 855-867 ◽  
Author(s):  
Igor V. Pekov ◽  
Natalia V. Zubkova ◽  
Vasiliy O. Yapaskurt ◽  
Yury S. Polekhovsky ◽  
Marina F. Vigasina ◽  
...  
Keyword(s):  
Kamchatka Peninsula ◽  
Scoria Cone ◽  
Structure Type ◽  
New Mineral ◽  
X Ray Diffraction ◽  
X Ray ◽  
Novel Structure ◽  
Reflected Light ◽  
Tolbachik Volcano ◽  
Mohs Hardness

AbstractThe new mineral melanarsite, K3Cu7Fe3+O4(AsO4)4, 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 Peninsula, Russia. It is associated with dmisokolovite, shchurovskyite, bradaczekite, hematite, tenorite, aphthitalite, johillerite, arsmirandite, As-bearing orthoclase, hatertite, pharmazincite, etc. Melanarsite occurs as tabular to prismatic crystals up to 0.4 mm, separate or combined in clusters up to 1 mm across or in interrupted crusts up to 0.02 cm × 1 cm × 1 cm covering basalt scoria. The mineral is opaque, black, with a vitreous lustre. Melanarsite is brittle. Mohs' hardness is ∼4 and the mean VHN = 203 kg mm–2. Cleavage was not observed and the fracture is uneven. Dcalc is 4.39 g cm–3. In reflected light, melanarsite is dark grey. Bireflectance is weak, anisotropism is very weak. Reflectance values [R1–R2, % (λ, nm)] are 10.5–9.4 (470), 10.0–8.9 (546), 9.7–8.7 (589), 9.5–8.6 (650). The Raman spectrum is reported. Chemical composition (wt.%, electron microprobe) is K2O 10.70, CaO 0.03, CuO 45.11, ZnO 0.24, Al2O3 0.32, Fe2O3 6.11, TiO2 0.12, P2O5 0.07, As2O5 36.86, total 99.56. The empirical formula, based on 20 O apfu, is (K2.81Ca0.01)∑2.82(Cu7.02Fe3+0.95Al0.08Zn0.04Ti0.02)∑8.11(As3.97P0.01)∑3.98O20. Melanarsite is monoclinic, C2/c, a = 11.4763(9), b = 16.620(2), c = 10.1322(8) Å, β = 105.078(9)°, V = 1866.0(3) Å3 and Z = 4. The strongest reflections of the powder X-ray diffraction pattern [d,Å(I)(hkl)] are 9.22(100)(110), 7.59(35)(1₃11), 6.084(17) (111), 4.595(26)(1₃31, 220, 2₃21), 3.124(22)(3₃31, 1₃51), 2.763(20)(400, 1₃52), 2.570(23)(043) and 2.473(16) (260, 2₃61, 350). Melanarsite has a novel structure type. Its crystal structure, solved from single-crystal X-ray diffraction data (R = 0.091), is based upon a heteropolyhedral pseudo-framework built by distorted Cu(1–3)O6 and (Fe,Cu)O6 octahedra and As(1–3)O4 tetrahedra. Two crystallographically independent K+ cations are located in the tunnels and voids of the pseudo-framework centring eight- and seven-fold polyhedra. The name reflects the mineral being an arsenate and its black colour (from the Greek μέλαν, black).

scholarly journals Petrovite, Na10CaCu2(SO4)8, a new fumarolic sulfate from the Great Tolbachik fissure eruption, Kamchatka Peninsula, Russia

2020 ◽  
Vol 84 (5) ◽  
pp. 691-698
Author(s):  
Stanislav K. Filatov ◽  
Andrey P. Shablinskii ◽  
Sergey V. Krivovichev ◽  
Lidiya P. Vergasova ◽  
Svetlana V. Moskaleva
Keyword(s):  
Three Dimensional ◽  
Kamchatka Peninsula ◽  
Scoria Cone ◽  
Fissure Eruption ◽  
Maximal Dimension ◽  
Chemical Formula ◽  
Crystal Chemical Formula ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mohs Hardness

AbstractPetrovite, Na10CaCu2(SO4)8, is a new sulfate mineral discovered on the Second scoria cone of the Great Tolbachik fissure eruption. The mineral occurs as globular aggregates of tabular crystals up to 0.2 mm in maximal dimension, generally with gaseous inclusions. The empirical formula calculated on the basis of O = 32 is Na6(Na1.80K0.20)Σ2Na(Ca0.82Na0.06Mg0.02)Σ0.90(Cu1.84Mg0.16)Σ2(Na0.52□0.48)Σ1S8.12O32. The crystal-chemical formula is CuNa6−2xCax(SO4)4, which, for x ≈ 0.5, results in the idealised formula Na10CaCu2(SO4)8. The crystal structure of petrovite was determined using single-crystal X-ray diffraction data; the space group is P21/c, a = 12.6346(8), b = 9.0760(6), c = 12.7560(8) Å, β = 108.75(9)°, V = 1385.1(3) Å3, Z = 2 and R1 = 0.051. There are one Cu and six Na sites, one of which is also occupied by the essential amount of Ca. The Cu atom forms five Cu–O bonds in the range 1.980–2.180 Å and two long bonds ≈ 2.9 Å resulting in the formation of the CuO7 polyhedra, which share corners with SO4 tetrahedra to form isolated [Cu2(SO4)8]12− clusters. The clusters are surrounded by Na sites, which provide their linkage into a three-dimensional framework. The Mohs’ hardness is 4. The mineral is biaxial (+), with α = 1.498(3), βcalc = 1.500, γ = 1.516(3) and 2V = 20(10) (λ = 589 nm). The seven strongest lines of the powder X-ray diffraction pattern [d, Å (I, %) (hkl)] are: 7.21(27)(110); 6.25(38)(102); 4.47(31)(212); 3.95(21)(30$\bar{2}$); 3.85(17)(121); 3.70(36)(202); and 3.65(34)(22$\bar{1}$). The mineral is named in honour of Prof Dr Tomas Georgievich Petrov (b. 1931) for his contributions to mineralogy and crystallography and, in particular, for the development of technology for the industrial fabrication of jewellery malachite.

Unique thallium mineralization in the fumaroles of Tolbachik volcano, Kamchatka Peninsula, Russia. I. Markhininite, TlBi(SO4)2

2014 ◽  
Vol 78 (7) ◽  
pp. 1687-1698 ◽  
Author(s):  
Oleg I. Siidra ◽  
Lidiya P. Vergasova ◽  
Sergey V. Krivovichev ◽  
Yuri L. Kretser ◽  
Anatoly N. Zaitsev ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Microprobe Analysis ◽  
Cinder Cone ◽  
Direct Methods ◽  
Kamchatka Peninsula ◽  
Single Crystal Diffraction ◽  
X Ray ◽  
The North ◽  
Tolbachik Volcano ◽  
Academy Of Sciences

AbstractMarkhininite, ideally TlBi(SO4)2, was found in a fumarole of the 1st cinder cone of the North Breach of the Great Fissure Tolbachik volcano eruption (1975–1976), Kamchatka Peninsula, Russia. Markhininite occurs as white pseudohexagonal plates associated with shcherbinaite, pauflerite, bobjonesite, karpovite, evdokimovite and microcrystalline Mg, Al, Fe and Na sulfates. Markhininite is triclinic, P1̄ , a = 7.378(3), b = 10.657(3), c = 10.657(3) Å , α = 61.31(3), β = 70.964(7), γ = 70.964(7)º, V = 680.2(4) Å3, Z = 4 (from single-crystal diffraction data). The eight strongest lines of the X-ray powder diffraction pattern are (I/d/hkl): 68/4.264/111, 100/3.441/113, 35/3.350/222, 24/3.125/122, 23/3.054/202, 45/2.717/022, 20/2.217/331, 34/2.114/204. Chemical composition determined by electron microprobe analysis is (wt.%): Tl2O 35.41, Bi2O3 38.91, SO3 25.19, total 99.51. The empirical formula based on 8 O a.p.f.u. is Tl1.04Bi1.05S1.97O8. The simplified formula is TlBi(SO4)2, which requires Tl2O 35.08, Bi2O3 38.48, SO3 26.44, total 100.00 wt.%. The crystal structure was solved by direct methods and refined to R1 = 0.055 on the basis of 1425 independent observed reflections. The structure contains four Tl+ and two Bi3+ sites in holodirected symmetrical coordination. BiO8 tetragonal antiprisms and SO4 tetrahedra in markhininite share common O atoms to produce [Bi(SO4)2]– layers of the yavapaiite type. The layers are parallel to (111) and linked together through interlayer Tl+ cations. The mineral is named in honour of Professor Yevgeniy Konstantinovich Markhinin (b. 1926), Institute of Volcanology, Russian Academy of Sciences, Kamchatka peninsula, Russia, in recognition of his contributions to volcanology. Markhininite is the first oxysalt compound that contains both Tl and Bi in an ordered crystal structure.

Maletoyvayamite, Au3Se4Te6, a new mineral from Maletoyvayam deposit, Kamchatka peninsula, Russia

2020 ◽  
Vol 84 (1) ◽  
pp. 117-123 ◽  
Author(s):  
Nadhezda D. Tolstykh ◽  
Marek Tuhý ◽  
Anna Vymazalová ◽  
Jakub Plášil ◽  
František Laufek ◽  
...  
Keyword(s):  
Kamchatka Peninsula ◽  
Structure Type ◽  
Van Der Waals Interactions ◽  
New Mineral ◽  
Synthetic Analogue ◽  
X Ray Diffraction ◽  
Calculated Density ◽  
Triclinic Space Group ◽  
Structural Identity ◽  
Polarised Light

AbstractMaletoyvayamite, Au3Se4Te6, is a new mineral discovered in a heavy-mineral concentrate from the Gaching occurrence of the Maletoyvayam deposit, Kamchatka, Russia (60°19′51.87″N, 164°46′25.65″E). It forms anhedral grains (10 to 50 μm in size) and is found in intergrowths with native gold (Au–Ag), Au tellurides (calaverite), unnamed phases (AuSe, Au2TeSe and Au oxide), native tellurium, sulfosalts (tennantite, tetrahedrite, goldfieldite and watanabeite) and supergene tripuhyite. Maletoyvayamite has a good cleavage on {010} and {001}. In plane-polarised light, maletoyvayamite is grey, has strong bireflectance (grey to bluish grey), and strong anisotropy; it exhibits no internal reflections. Reflectance values for maletoyvayamite in air (Rmin,Rmax in %) are: 38.9, 39.1 at 470 nm; 39.3, 39.5 at 546 nm; 39.3, 39.6 at 589 nm; and 39.4, 39.7 at 650 nm. Sixteen electron-microprobe analyses of maletoyvayamite gave an average composition: Au 34.46, Se 16.76, Te 47.23 and S 0.84, total 99.29 wt.%, corresponding to the formula Au2.90(Se3.52S0.44)Σ3.96Te6.14 based on 13 atoms; the average of eleven analyses on synthetic analogue is: Au 34.20, Se 19.68 and Te 45.42, total 99.30 wt.%, corresponding to Au2.90Se4.16Te5.94. The calculated density is 7.98 g/cm3. The mineral is triclinic, space group P1, with a = 8.901(2), b = 9.0451(14), c = 9.265(4) Å, α = 97.66(3), β = 106.70(2), γ = 101.399(14)°, V = 685.9(4) Å3 and Z = 2. The crystal structure of maletoyvayamite represents a unique structure type resembling a molecular structure. There are cube-like [Au6Se8Te12] clusters linked via van der Waals interactions. The structural identity of maletoyvayamite with the synthetic Au3Se4Te6 was confirmed by powder X-ray diffraction and Raman spectroscopy.

The crystal structure of kamchatkite, a new naturally occurring oxychloride sulphate of potassium and copper

1990 ◽  
Vol 54 (377) ◽  
pp. 613-616 ◽  
Author(s):  
T. V. Varaksina ◽  
V. S. Fundamensky ◽  
S.K. Filatov ◽  
L. P. Vergasova
Keyword(s):  
Crystal Structure ◽  
Three Dimensional ◽  
Direct Methods ◽  
New Mineral ◽  
Space Group ◽  
Naturally Occurring ◽  
Discrepancy Index ◽  
Oxygen Atoms

AbstractThe crystal structure of the new mineral kamchatkite, a= 9.741(5), b= 12.858(6), c=7.001(3)Å, space group Pna21, Z = 4, has been determined through direct methods using 1430 intensities and refined to a final discrepancy index R = 0.055. It contains (SO4) tetrahedra and Cu octahedra interconnected by oxygen atoms to form an electrostatically neutral three-dimensional arrangement of formula Cu3O[SO4]2 which contains channels parallel to [001]. The channels are not empty but house KCl molecules.

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