N. Zubkova | Lomonosov Moscow State University (original) (raw)
Papers by N. Zubkova
![Research paper thumbnail of Crystal structure of new synthetic calcium pentaborate Ca[B5O8(OH)] · H2O and its relation to pentaborates with similar boron-oxygen radicals](https://attachments.academia-assets.com/44882036/thumbnails/1.jpg)
](Crystallography Reports, 2003
A new representative of pentaborates with the composition Ca[B 5 O 8 (OH)] · H 2 O was synthesize... more A new representative of pentaborates with the composition Ca[B 5 O 8 (OH)] · H 2 O was synthesized under hydrothermal conditions within the framework of the study of phase formation in the CaCl 2 -Na 2 CO 3 -B 2 O 3 system. The crystal structure of the new pentaborate was established ( a = 6.5303(9) Å, b = 19.613(3) Å, c = 6.5303(9) Å, β = 119.207(2)° , V = 2513(2) Å 3 , sp. gr. P 2 1 / c , Z = 4, d calcd = 2.74 g/cm 3 , automated Brucker SMART CCD diffractometer, 6871 reflections, λ Mo radiation, anisotropic refinement by least-squares, R hkl = 0.076). The structure of calcium pentaborate is built by isolated B-Ca-B stacks parallel to the (010) plane. The central fragments of these stacks consists of nine-vertex Ca polyhedra. The Ca layers are located between loose B-O networks composed of [ O 8 (OH)] 2pentaborate groups. The arrangement of the polyhedra around large cations in pentaborates with groups of two B tetrahedra and three B triangles was analyzed in terms of crystal chemistry. It is established that the structures of these compounds consist of large isolated polyhedra, columns, layers, and three-dimensional frameworks.
Crystallography Reports, 2011
The crystal structure of larnite, a natural analog of synthetic β Ca 2 SiO 4 , has been determine... more The crystal structure of larnite, a natural analog of synthetic β Ca 2 SiO 4 , has been determined: a = 5.5051(3) Å, b = 6.7551(3) Å, c = 9.3108(5) Å, β = 94.513(4)º, sp. gr. P2 1 /n, and R 1 = 0.0532 for 1071 reflec tions with I > 2σ (I). Larnite was found in skarn xenoliths (Lakargi, Kabardino Balkaria, Russia). The min eral structure is based on a heteropolyhedral glaserite like framework of interconnected Ca polyhedra and isolated [SiO 4 ] tetrahedra. Based on an analysis of the layer by layer packing of atoms in the structures of lar nite and other Ca 2 SiO 4 polymorphs, the structural features and mechanisms of transitions from high tem perature (α, ) to low temperature (β and γ) Ca 2 SiO 4 modifications, as well as their relationship with natural glaserite like orthosilicates (merwinite Ca 3 Mg[SiO 4 ] 2 and bredigite Ca 7 Mg[SiO 4 ] 4 ), have been considered. The most likely atomic arrangement in hypothetical Ca 2 SiO 4 models has been calculated by the method of atomistic potentials.
Crystallography Reports, 2009
ABSTRACT A new representative of pentaborates with the composition Ca[B5O8(OH)] H2O was synthesiz... more ABSTRACT A new representative of pentaborates with the composition Ca[B5O8(OH)] H2O was synthesized under hydrothermal conditions within the framework of the study of phase formation in the CaCl2-Na2CO3-B2O3 system. The crystal structure of the new pentaborate was established (a = 6.5303(9) Å, b = 19.613(3) Å, c = 6.5303(9) Å, β = 119.207(2), V = 2513(2) Å3, sp. gr. P21/c, Z = 4, d calcd = 2.74 g/cm3, automated Brucker SMART CCD diffractometer, 6871 reflections, λMo radiation, anisotropic refinement by least-squares, R hkl = 0.076). The structure of calcium pentaborate is built by isolated B-Ca-B stacks parallel to the (010) plane. The central fragments of these stacks consists of nine-vertex Ca polyhedra. The Ca layers are located between loose B-O networks composed of [B 2 t B 3 Δ O8(OH)]2− pentaborate groups. The arrangement of the polyhedra around large cations in pentaborates with groups of two B tetrahedra and three B triangles was analyzed in terms of crystal chemistry. It is established that the structures of these compounds consist of large isolated polyhedra, columns, layers, and three-dimensional frameworks.
Crystallography Reports, 2005
A calcium analog of strontioborite, namely, Ca[B8O11(OH)4], is synthesized under hydrothermal con... more A calcium analog of strontioborite, namely, Ca[B8O11(OH)4], is synthesized under hydrothermal conditions (T = 270C, P = 20 atm) within the framework of the study of the phase formation in the CaCl2 Rb2CO3 B2O3 system. The crystal structure of the synthetic calcium borate [a = 7.4480(5) Å, b = 8.2627(5) Å, c = 9.8102(6) Å, β = 108.331(1), V = 573.09(6) Å3, space group P21, Z = 2, ρcalcd = 2.15 g/cm3; Brucker SMART CCD automated diffractometer, 5506 reflections, λMoK α] is refined by the least-squares procedure in the anisotropic approximation of thermal atomic vibrations to R 1 = 0.050. The calcium borate studied has a crystal structure identical to the structure of the natural strontium borate (strontioborite) Sr[B8O11(OH)4] and its calcium analog synthesized earlier. The crystal structure is built up of stacks consisting of skeleton layers (formed by boron-oxygen polyanions) and isolated strontium (calcium) polyhedra located in trigonal holes of the skeleton layers. Through channels that can contain H2O molecules are formed between the stacks. The structure refinement and analysis of the IR spectrum of the synthetic calcium analog of strontioborite do not confirm the previously proposed hypothesis that water molecules are involved in the channels of the structure. A comparative crystal chemical analysis of the calcium borate under investigation and its formula analog, namely, the lead borate Pb[B8O11(OH)4], is performed.
Crystallography Reports, 2007
The phosphorus-rich variety of ellenbergerite (Mg 0.61 Ti 0.08 ᮀ 0.31 ) 2 (Mg 0.52 Al 0.43 ᮀ 0.05... more The phosphorus-rich variety of ellenbergerite (Mg 0.61 Ti 0.08 ᮀ 0.31 ) 2 (Mg 0.52 Al 0.43 ᮀ 0.05 ) 12 [SiO 3 (O 0.29 (OH) 0.71 )] 6 [(P 0.71 Si 0.20 ᮀ 0.09 )O 3 OH] 2 (OH) 6 was studied by X-ray diffraction and IR spectroscopy. The structure was refined in sp. gr. P 6 3 mc to R = 0.0248. The structure of phosphorus-rich ellenbergerite retains the octahedral framework observed in the structures of ellenbergerite, phosphoellenbergerite, ekatite, and a series of structurally related synthetic compounds. The structure of phosphorus-rich ellenbergerite differs from the structure of ellenbergerite primarily in that the Mg and Al cations in the phosphorus-rich variety are disordered in the octahedra of the framework, thereby leading to higher symmetry, and the channels of triangular cross section are occupied predominantly by P tetrahedra.
Inorganic Materials, 2011
The structural transformations accompanying the thermal dehydration of natural elpidite, Na2ZrSi6... more The structural transformations accompanying the thermal dehydration of natural elpidite, Na2ZrSi6O15 · 3H2O, have been studied by X-ray powder diffraction and IR spectroscopy. The crystal structures of both elpidite (a = 7.1136(1), b = 14.6764(2), c = 14.5977(2) Å; sp. Gr. Pbcm) and the dehydration product Na2ZrSi6O15 (a = 14.0899(1), b = 14.4983(1), c = 14.3490(1)Å; sp. gr. Cmce =
American Mineralogist
Correianevesite, ideally Fe2+Mn22+(PO4)2 center dot 3H(2)O, is a new reddingite-group mineral app... more Correianevesite, ideally Fe2+Mn22+(PO4)2 center dot 3H(2)O, is a new reddingite-group mineral approved by the CNMNC (IMA 2013-007). It occurs in a phosphate-rich granite pegmatite that outcrops near the Cigana mine. Conselheiro Pena. Rio Doce valley, Minas Gerais, Brazil. Associated minerals are: triphylite, lithiophilite, frondelite, rockbridgeite, eosphorite, vivianite, fairfieldite, leucophosphite, cyrilovite, phosphosiderite. etc. Correianevesite occurs as grayish-brown to reddish-brown transparent bipyramidal crystals up to 4 mm in size. The streak is white, and the luster is vitreous. Mohs hardness is 3,4, Cleavage is poor on (010). Fracture is laminated, uneven across cleavage. The measured density is 3.25(2) g/cm(3); the calculated density is 3.275 g/cm(3). The mineral is biaxial (+), alpha = 1.661(5), beta = 1.673(5), gamma = 1.703(5), 2 V-meas = 70(10)degrees(eale), 2V(eale) = 65.6. The IR spectrum confirms the presence of H2O. The Mossbauer spectrum shows the presence of ...
Minerals as Advanced Materials II, 2011
Mineralogical Magazine, 2014
ABSTRACT The new mineral popovite, Cu5O2(AsO4)2, was found in the sublimates of the Arsenatnaya f... more 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. D calc is 5.30 g cm–3. Popovite is optically biaxial (+), α = 1.84(1), β ≈ 1.86, γ = 1.96(1), 2V meas = 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, P1, 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)(111), 2.968(90)(012), 2.927(100)(111), 2.782(31)(102), 2.768(67)(120), 2.513(55)(121) and 2.462(67)(201). 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.
Inorganic Materials, 2012
ABSTRACT The crystal structure of the mineral creedite (hydrous calcium aluminum sulfate fluoride... more ABSTRACT The crystal structure of the mineral creedite (hydrous calcium aluminum sulfate fluoride, Ca(3)Al(2)(F,OH)(10)(SO(4)) center dot 2H(2)O) has been determined by Rietveld powder diffraction analysis. X-ray diffraction data obtained in the temperature range from 25 to 470A degrees C indicate that the crystal structure of creedite is stable up to 390A degrees C. We have measured the unit-cell parameters of creedite as functions of temperature and determined its thermal expansion coefficients. Above 390A degrees C, the mineral decomposes.
Zeitschrift für Kristallographie, 2000
ABSTRACT
Zeitschrift für Kristallographie, 2000
Mineralogical Magazine, 2010
Mineralogical Magazine, 2012
ABSTRACT The new mineral calciolangbeinite, ideally K2Ca2(SO4)3, is the Ca-dominant analogue of l... more ABSTRACT The new mineral calciolangbeinite, ideally K2Ca2(SO4)3, is the Ca-dominant analogue of langbeinite. It occurs in sublimates at the Yadovitaya fumarole on the Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure eruption, Tolbachik volcano, Kamchatka, Russia. The mineral is associated with langbeinite, piypite, hematite, rutile, pseudobrookite, orthoclase, lyonsite, lammerite, cyanochroite and chlorothionite. Calciolangbeinite occurs as tetrahedral to pseudooctahedral crystals, which are bounded by {111} and {111}, and as anhedral grains up to 1 mm in size, aggregated into clusters up to 2 mm across, and forming crusts covering areas of up to 1.5 6 1.5 cm on the surface of volcanic scoria. Late-stage calciolangbeinite occurs in complex epitaxial intergrowths with langbeinite. Calciolangbeinite is transparent and colourless with white streak and vitreous lustre. Its Mohs' hardness is 3-3½. It is brittle, has a conchoidal fracture and no obvious cleavage. The measured and calculated densities are Dmeas = 2.68(2) and Dcalc = 2.74 g cm-3, respectively. Calciolangbeinite is optically isotropic with n = 1.527(2). The chemical composition of the holotype specimen is Na2O 0.38, K2O 21.85, MgO 6.52, CaO 16.00, MnO 0.27, FeO 0.08, Al2O3 0.09, SO3 55.14, total 100.63 wt.%. The empirical formula, calculated on the basis of twelve oxygen atoms per formula unit, is K2.01(Ca1.24Mg0.70Na0.05Mn0.02Fe0.01Al0.01)S 2.03S3.00O12. Calciolangbeinite is cubic, space group P213, a = 10.1887(4) Å, V = 1057.68(4) Å3 and Z = 4. The strongest reflections in the X-ray powder pattern [listed as (d, Å (I)(hkl)] are 5.84(8)(111); 4.54(9)(120); 4.15(27)(211); 3.218 (100) (310, 130); 2.838 (8) (230, 320), 2.736 (37) (231, 321), 2.006 (11) (431, 341) , 1.658(8)(611,532,352). The crystal structure was refined from single-crystal X-ray diffraction data to R = 0.0447. The structure is based on the langbeinite-type three-dimensional complex framework, which is made up of (Ca,Mg)O6 octahedra (Ca and Mg are disordered) and SO4 tetrahedra. Potassium atoms occupy two sites in voids in the framework; K(1) cations are located in ninefold polyhedra whereas K(2) cations are sited in significantly distorted octahedra. Calciolangbeinite and langbeinite are isostructural and form a solid-solution series.
Geology of Ore Deposits, 2013
ABSTRACT A new mineral vigrishinite, epistolite-group member and first layer titanosilicate with ... more ABSTRACT A new mineral vigrishinite, epistolite-group member and first layer titanosilicate with species-defining Zn, was found at Mt. Malyi Punkaruaiv, in the Lovozero alkaline complex, Kola Peninsula, Russia. It occurs in a hydrothermally altered peralkaline pegmatite and is associated with microcline, ussingite, aegirine, analcime, gmelinite-Na, and chabazite-Ca. Vigrishinite forms rectangular or irregularly shaped lamellae up to 0.05 × 2 × 3 cm flattened on [001]. They are typically slightly split and show blocky character. The mineral is translucent to transparent and pale pink, yellowish-pinkish or colorless. The luster is vitreous. The Mohs’ hardness is 2.5–3. Vigrishinite is brittle. Cleavage is {001} perfect. D meas = 3.03(2), D calc = 2.97 g/cm3. The mineral is optically biaxial (−), α = 1.755(5), β = 1.82(1), γ = 1.835(8), 2V meas = 45(10)°, 2V calc = 50°. IR spectrum is given. The chemical composition (wt %; average of 9 point analyses, H2O is determined by modified Penfield method) is as follows: 0.98 Na2O, 0.30 K2O, 0.56 CaO, 0.05 SrO, 0.44 BaO, 0.36 MgO, 2.09 MnO, 14.39 ZnO, 2.00 Fe2O3, 0.36 Al2O3, 32.29 SiO2, 29.14 TiO2, 2.08 ZrO2, 7.34 Nb2O5, 0.46 F, 9.1 H2O, −0.19 O=F2, total is 101.75. The empirical formula calculated on the basis of Si + Al = 4 is: H7.42(Zn1.30Na0.23Mn0.22Ca0.07Mg0.07K0.05Ba0.02)Σ1.96(Ti2.68Nb0.41Fe 0.183+ Zr0.12)Σ3.39(Si3.95Al0.05)Σ420.31F0.18. The simplified formula is: Zn2Ti4−x Si4O14(OH,H2O,□)8 (x P , a = 8.743(9), b = 8.698(9), c = 11.581(11)Å, α = 91.54(8)°, β = 98.29(8)°, γ = 105.65(8)°, V = 837.2(1.5) Å3, Z = 2. The strongest reflections in the X-ray powder pattern (D, Å, −I[hkl]) are: 11.7-67[001], 8.27-50[100], 6.94-43[0 1, 10], 5.73–54[1 1, 002], 4.17-65[020, 2, 200], and 2.861-100[3 0, 2 2, 004, 1 1]. The crystal structure model was obtained on a single crystal, R = 0.171. Vigrishinite and murmanite are close in the structure of the TiSiO motif, but strongly differ from each other in part of large cations and H-bearing groups. Vigrishinite is named in honor of Viktor G. Grishin (b. 1953), a Russian amateur mineralogist and mineral collector, to pay tribute to his contribution to the mineralogy of the Lovozero Complex. The type specimen is deposited in the Fersman Mineralogical Museum of Russian Academy of Sciences, Moscow.
Geology of Ore Deposits, 2010
ABSTRACT Voloshinite, a new mineral of the mica group, a rubidium analogue of lepidolite, has bee... more ABSTRACT Voloshinite, a new mineral of the mica group, a rubidium analogue of lepidolite, has been found from the rare-element granitic pegmatite at Mt. Vasin-Myl’k, Voron’i Tundras, Kola Peninsula, Russia. It is closely associated with pollucite and lepidolite and commonly with muscovite, albite, and quartz; K,Rb-feldspar, rubicline, spodumene, montebrasite, and elbaite are among associated minerals as well. Voloshinite, a late mineral that formed after pollucite, commonly fills polymineralic veinlets and pods within the pollucite aggregates. It occurs as rims up to 0.05 mm thick around lepidolite, as intergrowths of tabular crystals up to 0.25 mm in size, and occasionally replaces lepidolite. The new mineral is colorless, transparent, with vitreous luster. Cleavage is eminent parallel to {001}; flakes are flexible. The calculated density is 2.95 g/cm3. The new mineral is biaxial (−), with 2V = 25°, α calc = 1.511, β = 1.586, and γ = 1.590. The optical orientation is Y = b, Z = a. The chemical composition of the type material determined by electron microprobe (average of five point analyses; Li has been determined with ICP-OES) is as follows (wt %): 0.03 Na2O, 3.70 K2O, 12.18 Rb2O, 2.02 Cs2O, 4.0 Li2O, 0.03 CaO, 0.02 MgO, 0.14 MnO, 21.33 Al2O3, 53.14 SiO2, 6.41 F, -O = F2 2.70, total is 100.30. The empirical formula is: (Rb0.54K0.33Cs0.06)Σ0.93(Al1.42Li1.11Mn0.01)Σ2.54(Si3.68Al0.32)Σ4O10 (F1.40(OH)0.60)Σ2. The idealized formula is as follows: Rb(LiAl1.5□0.5)[Al0.5Si3.5O10]F2. Voloshinite forms a continuous solid solution with lepidolite. According to X-ray single crystal study, voloshinite is monoclinic, space group C2/c. The unit-cell dimensions are: a = 5.191, b = 9.025, c = 20.40 Å, β = 95.37°, V= 951.5 Å3, Z = 4. Polytype is 2M 1. The strongest reflections in the X-ray powder diffraction pattern (d, Å-I[hkl]) are: 10.1-60[001]; 4.55-80[020, 110, 11$ \bar 1 $ \bar 1 ]; 3.49-50[11$ \bar 4 $ \bar 4 ]; 3.35-60[024, 006]; 3.02-45[025]; 2.575-100[11$ \bar 6 $ \bar 6 , 131, 20$ \bar 2 $ \bar 2 , 13$ \bar 4 $ \bar 4 ], 2.017-50[136, 0.0.10]. The mineral was named in honor of A.V. Voloshin (born in 1937), the famous Russian mineralogist. The type material is deposited at the Fersman Mineralogical Museum of the Russian Academy of Sciences, Moscow.
![Research paper thumbnail of Yegorovite, Na4[Si4O8(OH)4]·7H2O, a new mineral from the Lovozero alkaline pluton, Kola Peninsula](https://attachments.academia-assets.com/44825832/thumbnails/1.jpg)
](Geology of Ore Deposits, 2010
Geology of Ore Deposits, 2009
![Research paper thumbnail of Chesnokovite, Na2[SiO2(OH)2] · 8H2O, the first natural sodium orthosilicate from the Lovozero alkaline pluton, Kola Peninsula: Description and crystal structure of a new mineral species](https://attachments.academia-assets.com/44825826/thumbnails/1.jpg)
](Geology of Ore Deposits, 2007
family were described for the first time only 40 years ago after the discovery of magadiite and k... more family were described for the first time only 40 years ago after the discovery of magadiite and kenyaite in the soda-bearing sediments of Lake Magadi, Kenya . A few years later, makatite and kanemite also found in the sediments of African soda lakes were described by and . Other findings in a similar environment showed that hydrous sodium silicates are characteristic of alkali carbonate supergene, foremost, the sedex-type mineral assemblages. Subsequently, the members of this family were described from a quite different setting. Makatite and new minerals-revdite and grumantite-were found in the salt mineralization of the late, low-temperature derivates of hyperalkaline igneous rocks in the Lovozero alkaline pluton, Kola Peninsula, Russia (Khomyakov et al.
Crystallography Reports, 2003
A new representative of pentaborates with the composition Ca[B 5 O 8 (OH)] · H 2 O was synthesize... more A new representative of pentaborates with the composition Ca[B 5 O 8 (OH)] · H 2 O was synthesized under hydrothermal conditions within the framework of the study of phase formation in the CaCl 2 -Na 2 CO 3 -B 2 O 3 system. The crystal structure of the new pentaborate was established ( a = 6.5303(9) Å, b = 19.613(3) Å, c = 6.5303(9) Å, β = 119.207(2)° , V = 2513(2) Å 3 , sp. gr. P 2 1 / c , Z = 4, d calcd = 2.74 g/cm 3 , automated Brucker SMART CCD diffractometer, 6871 reflections, λ Mo radiation, anisotropic refinement by least-squares, R hkl = 0.076). The structure of calcium pentaborate is built by isolated B-Ca-B stacks parallel to the (010) plane. The central fragments of these stacks consists of nine-vertex Ca polyhedra. The Ca layers are located between loose B-O networks composed of [ O 8 (OH)] 2pentaborate groups. The arrangement of the polyhedra around large cations in pentaborates with groups of two B tetrahedra and three B triangles was analyzed in terms of crystal chemistry. It is established that the structures of these compounds consist of large isolated polyhedra, columns, layers, and three-dimensional frameworks.
Crystallography Reports, 2011
The crystal structure of larnite, a natural analog of synthetic β Ca 2 SiO 4 , has been determine... more The crystal structure of larnite, a natural analog of synthetic β Ca 2 SiO 4 , has been determined: a = 5.5051(3) Å, b = 6.7551(3) Å, c = 9.3108(5) Å, β = 94.513(4)º, sp. gr. P2 1 /n, and R 1 = 0.0532 for 1071 reflec tions with I > 2σ (I). Larnite was found in skarn xenoliths (Lakargi, Kabardino Balkaria, Russia). The min eral structure is based on a heteropolyhedral glaserite like framework of interconnected Ca polyhedra and isolated [SiO 4 ] tetrahedra. Based on an analysis of the layer by layer packing of atoms in the structures of lar nite and other Ca 2 SiO 4 polymorphs, the structural features and mechanisms of transitions from high tem perature (α, ) to low temperature (β and γ) Ca 2 SiO 4 modifications, as well as their relationship with natural glaserite like orthosilicates (merwinite Ca 3 Mg[SiO 4 ] 2 and bredigite Ca 7 Mg[SiO 4 ] 4 ), have been considered. The most likely atomic arrangement in hypothetical Ca 2 SiO 4 models has been calculated by the method of atomistic potentials.
Crystallography Reports, 2009
ABSTRACT A new representative of pentaborates with the composition Ca[B5O8(OH)] H2O was synthesiz... more ABSTRACT A new representative of pentaborates with the composition Ca[B5O8(OH)] H2O was synthesized under hydrothermal conditions within the framework of the study of phase formation in the CaCl2-Na2CO3-B2O3 system. The crystal structure of the new pentaborate was established (a = 6.5303(9) Å, b = 19.613(3) Å, c = 6.5303(9) Å, β = 119.207(2), V = 2513(2) Å3, sp. gr. P21/c, Z = 4, d calcd = 2.74 g/cm3, automated Brucker SMART CCD diffractometer, 6871 reflections, λMo radiation, anisotropic refinement by least-squares, R hkl = 0.076). The structure of calcium pentaborate is built by isolated B-Ca-B stacks parallel to the (010) plane. The central fragments of these stacks consists of nine-vertex Ca polyhedra. The Ca layers are located between loose B-O networks composed of [B 2 t B 3 Δ O8(OH)]2− pentaborate groups. The arrangement of the polyhedra around large cations in pentaborates with groups of two B tetrahedra and three B triangles was analyzed in terms of crystal chemistry. It is established that the structures of these compounds consist of large isolated polyhedra, columns, layers, and three-dimensional frameworks.
Crystallography Reports, 2005
A calcium analog of strontioborite, namely, Ca[B8O11(OH)4], is synthesized under hydrothermal con... more A calcium analog of strontioborite, namely, Ca[B8O11(OH)4], is synthesized under hydrothermal conditions (T = 270C, P = 20 atm) within the framework of the study of the phase formation in the CaCl2 Rb2CO3 B2O3 system. The crystal structure of the synthetic calcium borate [a = 7.4480(5) Å, b = 8.2627(5) Å, c = 9.8102(6) Å, β = 108.331(1), V = 573.09(6) Å3, space group P21, Z = 2, ρcalcd = 2.15 g/cm3; Brucker SMART CCD automated diffractometer, 5506 reflections, λMoK α] is refined by the least-squares procedure in the anisotropic approximation of thermal atomic vibrations to R 1 = 0.050. The calcium borate studied has a crystal structure identical to the structure of the natural strontium borate (strontioborite) Sr[B8O11(OH)4] and its calcium analog synthesized earlier. The crystal structure is built up of stacks consisting of skeleton layers (formed by boron-oxygen polyanions) and isolated strontium (calcium) polyhedra located in trigonal holes of the skeleton layers. Through channels that can contain H2O molecules are formed between the stacks. The structure refinement and analysis of the IR spectrum of the synthetic calcium analog of strontioborite do not confirm the previously proposed hypothesis that water molecules are involved in the channels of the structure. A comparative crystal chemical analysis of the calcium borate under investigation and its formula analog, namely, the lead borate Pb[B8O11(OH)4], is performed.
Crystallography Reports, 2007
The phosphorus-rich variety of ellenbergerite (Mg 0.61 Ti 0.08 ᮀ 0.31 ) 2 (Mg 0.52 Al 0.43 ᮀ 0.05... more The phosphorus-rich variety of ellenbergerite (Mg 0.61 Ti 0.08 ᮀ 0.31 ) 2 (Mg 0.52 Al 0.43 ᮀ 0.05 ) 12 [SiO 3 (O 0.29 (OH) 0.71 )] 6 [(P 0.71 Si 0.20 ᮀ 0.09 )O 3 OH] 2 (OH) 6 was studied by X-ray diffraction and IR spectroscopy. The structure was refined in sp. gr. P 6 3 mc to R = 0.0248. The structure of phosphorus-rich ellenbergerite retains the octahedral framework observed in the structures of ellenbergerite, phosphoellenbergerite, ekatite, and a series of structurally related synthetic compounds. The structure of phosphorus-rich ellenbergerite differs from the structure of ellenbergerite primarily in that the Mg and Al cations in the phosphorus-rich variety are disordered in the octahedra of the framework, thereby leading to higher symmetry, and the channels of triangular cross section are occupied predominantly by P tetrahedra.
Inorganic Materials, 2011
The structural transformations accompanying the thermal dehydration of natural elpidite, Na2ZrSi6... more The structural transformations accompanying the thermal dehydration of natural elpidite, Na2ZrSi6O15 · 3H2O, have been studied by X-ray powder diffraction and IR spectroscopy. The crystal structures of both elpidite (a = 7.1136(1), b = 14.6764(2), c = 14.5977(2) Å; sp. Gr. Pbcm) and the dehydration product Na2ZrSi6O15 (a = 14.0899(1), b = 14.4983(1), c = 14.3490(1)Å; sp. gr. Cmce =
American Mineralogist
Correianevesite, ideally Fe2+Mn22+(PO4)2 center dot 3H(2)O, is a new reddingite-group mineral app... more Correianevesite, ideally Fe2+Mn22+(PO4)2 center dot 3H(2)O, is a new reddingite-group mineral approved by the CNMNC (IMA 2013-007). It occurs in a phosphate-rich granite pegmatite that outcrops near the Cigana mine. Conselheiro Pena. Rio Doce valley, Minas Gerais, Brazil. Associated minerals are: triphylite, lithiophilite, frondelite, rockbridgeite, eosphorite, vivianite, fairfieldite, leucophosphite, cyrilovite, phosphosiderite. etc. Correianevesite occurs as grayish-brown to reddish-brown transparent bipyramidal crystals up to 4 mm in size. The streak is white, and the luster is vitreous. Mohs hardness is 3,4, Cleavage is poor on (010). Fracture is laminated, uneven across cleavage. The measured density is 3.25(2) g/cm(3); the calculated density is 3.275 g/cm(3). The mineral is biaxial (+), alpha = 1.661(5), beta = 1.673(5), gamma = 1.703(5), 2 V-meas = 70(10)degrees(eale), 2V(eale) = 65.6. The IR spectrum confirms the presence of H2O. The Mossbauer spectrum shows the presence of ...
Minerals as Advanced Materials II, 2011
Mineralogical Magazine, 2014
ABSTRACT The new mineral popovite, Cu5O2(AsO4)2, was found in the sublimates of the Arsenatnaya f... more 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. D calc is 5.30 g cm–3. Popovite is optically biaxial (+), α = 1.84(1), β ≈ 1.86, γ = 1.96(1), 2V meas = 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, P1, 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)(111), 2.968(90)(012), 2.927(100)(111), 2.782(31)(102), 2.768(67)(120), 2.513(55)(121) and 2.462(67)(201). 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.
Inorganic Materials, 2012
ABSTRACT The crystal structure of the mineral creedite (hydrous calcium aluminum sulfate fluoride... more ABSTRACT The crystal structure of the mineral creedite (hydrous calcium aluminum sulfate fluoride, Ca(3)Al(2)(F,OH)(10)(SO(4)) center dot 2H(2)O) has been determined by Rietveld powder diffraction analysis. X-ray diffraction data obtained in the temperature range from 25 to 470A degrees C indicate that the crystal structure of creedite is stable up to 390A degrees C. We have measured the unit-cell parameters of creedite as functions of temperature and determined its thermal expansion coefficients. Above 390A degrees C, the mineral decomposes.
Zeitschrift für Kristallographie, 2000
ABSTRACT
Zeitschrift für Kristallographie, 2000
Mineralogical Magazine, 2010
Mineralogical Magazine, 2012
ABSTRACT The new mineral calciolangbeinite, ideally K2Ca2(SO4)3, is the Ca-dominant analogue of l... more ABSTRACT The new mineral calciolangbeinite, ideally K2Ca2(SO4)3, is the Ca-dominant analogue of langbeinite. It occurs in sublimates at the Yadovitaya fumarole on the Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure eruption, Tolbachik volcano, Kamchatka, Russia. The mineral is associated with langbeinite, piypite, hematite, rutile, pseudobrookite, orthoclase, lyonsite, lammerite, cyanochroite and chlorothionite. Calciolangbeinite occurs as tetrahedral to pseudooctahedral crystals, which are bounded by {111} and {111}, and as anhedral grains up to 1 mm in size, aggregated into clusters up to 2 mm across, and forming crusts covering areas of up to 1.5 6 1.5 cm on the surface of volcanic scoria. Late-stage calciolangbeinite occurs in complex epitaxial intergrowths with langbeinite. Calciolangbeinite is transparent and colourless with white streak and vitreous lustre. Its Mohs' hardness is 3-3½. It is brittle, has a conchoidal fracture and no obvious cleavage. The measured and calculated densities are Dmeas = 2.68(2) and Dcalc = 2.74 g cm-3, respectively. Calciolangbeinite is optically isotropic with n = 1.527(2). The chemical composition of the holotype specimen is Na2O 0.38, K2O 21.85, MgO 6.52, CaO 16.00, MnO 0.27, FeO 0.08, Al2O3 0.09, SO3 55.14, total 100.63 wt.%. The empirical formula, calculated on the basis of twelve oxygen atoms per formula unit, is K2.01(Ca1.24Mg0.70Na0.05Mn0.02Fe0.01Al0.01)S 2.03S3.00O12. Calciolangbeinite is cubic, space group P213, a = 10.1887(4) Å, V = 1057.68(4) Å3 and Z = 4. The strongest reflections in the X-ray powder pattern [listed as (d, Å (I)(hkl)] are 5.84(8)(111); 4.54(9)(120); 4.15(27)(211); 3.218 (100) (310, 130); 2.838 (8) (230, 320), 2.736 (37) (231, 321), 2.006 (11) (431, 341) , 1.658(8)(611,532,352). The crystal structure was refined from single-crystal X-ray diffraction data to R = 0.0447. The structure is based on the langbeinite-type three-dimensional complex framework, which is made up of (Ca,Mg)O6 octahedra (Ca and Mg are disordered) and SO4 tetrahedra. Potassium atoms occupy two sites in voids in the framework; K(1) cations are located in ninefold polyhedra whereas K(2) cations are sited in significantly distorted octahedra. Calciolangbeinite and langbeinite are isostructural and form a solid-solution series.
Geology of Ore Deposits, 2013
ABSTRACT A new mineral vigrishinite, epistolite-group member and first layer titanosilicate with ... more ABSTRACT A new mineral vigrishinite, epistolite-group member and first layer titanosilicate with species-defining Zn, was found at Mt. Malyi Punkaruaiv, in the Lovozero alkaline complex, Kola Peninsula, Russia. It occurs in a hydrothermally altered peralkaline pegmatite and is associated with microcline, ussingite, aegirine, analcime, gmelinite-Na, and chabazite-Ca. Vigrishinite forms rectangular or irregularly shaped lamellae up to 0.05 × 2 × 3 cm flattened on [001]. They are typically slightly split and show blocky character. The mineral is translucent to transparent and pale pink, yellowish-pinkish or colorless. The luster is vitreous. The Mohs’ hardness is 2.5–3. Vigrishinite is brittle. Cleavage is {001} perfect. D meas = 3.03(2), D calc = 2.97 g/cm3. The mineral is optically biaxial (−), α = 1.755(5), β = 1.82(1), γ = 1.835(8), 2V meas = 45(10)°, 2V calc = 50°. IR spectrum is given. The chemical composition (wt %; average of 9 point analyses, H2O is determined by modified Penfield method) is as follows: 0.98 Na2O, 0.30 K2O, 0.56 CaO, 0.05 SrO, 0.44 BaO, 0.36 MgO, 2.09 MnO, 14.39 ZnO, 2.00 Fe2O3, 0.36 Al2O3, 32.29 SiO2, 29.14 TiO2, 2.08 ZrO2, 7.34 Nb2O5, 0.46 F, 9.1 H2O, −0.19 O=F2, total is 101.75. The empirical formula calculated on the basis of Si + Al = 4 is: H7.42(Zn1.30Na0.23Mn0.22Ca0.07Mg0.07K0.05Ba0.02)Σ1.96(Ti2.68Nb0.41Fe 0.183+ Zr0.12)Σ3.39(Si3.95Al0.05)Σ420.31F0.18. The simplified formula is: Zn2Ti4−x Si4O14(OH,H2O,□)8 (x P , a = 8.743(9), b = 8.698(9), c = 11.581(11)Å, α = 91.54(8)°, β = 98.29(8)°, γ = 105.65(8)°, V = 837.2(1.5) Å3, Z = 2. The strongest reflections in the X-ray powder pattern (D, Å, −I[hkl]) are: 11.7-67[001], 8.27-50[100], 6.94-43[0 1, 10], 5.73–54[1 1, 002], 4.17-65[020, 2, 200], and 2.861-100[3 0, 2 2, 004, 1 1]. The crystal structure model was obtained on a single crystal, R = 0.171. Vigrishinite and murmanite are close in the structure of the TiSiO motif, but strongly differ from each other in part of large cations and H-bearing groups. Vigrishinite is named in honor of Viktor G. Grishin (b. 1953), a Russian amateur mineralogist and mineral collector, to pay tribute to his contribution to the mineralogy of the Lovozero Complex. The type specimen is deposited in the Fersman Mineralogical Museum of Russian Academy of Sciences, Moscow.
Geology of Ore Deposits, 2010
ABSTRACT Voloshinite, a new mineral of the mica group, a rubidium analogue of lepidolite, has bee... more ABSTRACT Voloshinite, a new mineral of the mica group, a rubidium analogue of lepidolite, has been found from the rare-element granitic pegmatite at Mt. Vasin-Myl’k, Voron’i Tundras, Kola Peninsula, Russia. It is closely associated with pollucite and lepidolite and commonly with muscovite, albite, and quartz; K,Rb-feldspar, rubicline, spodumene, montebrasite, and elbaite are among associated minerals as well. Voloshinite, a late mineral that formed after pollucite, commonly fills polymineralic veinlets and pods within the pollucite aggregates. It occurs as rims up to 0.05 mm thick around lepidolite, as intergrowths of tabular crystals up to 0.25 mm in size, and occasionally replaces lepidolite. The new mineral is colorless, transparent, with vitreous luster. Cleavage is eminent parallel to {001}; flakes are flexible. The calculated density is 2.95 g/cm3. The new mineral is biaxial (−), with 2V = 25°, α calc = 1.511, β = 1.586, and γ = 1.590. The optical orientation is Y = b, Z = a. The chemical composition of the type material determined by electron microprobe (average of five point analyses; Li has been determined with ICP-OES) is as follows (wt %): 0.03 Na2O, 3.70 K2O, 12.18 Rb2O, 2.02 Cs2O, 4.0 Li2O, 0.03 CaO, 0.02 MgO, 0.14 MnO, 21.33 Al2O3, 53.14 SiO2, 6.41 F, -O = F2 2.70, total is 100.30. The empirical formula is: (Rb0.54K0.33Cs0.06)Σ0.93(Al1.42Li1.11Mn0.01)Σ2.54(Si3.68Al0.32)Σ4O10 (F1.40(OH)0.60)Σ2. The idealized formula is as follows: Rb(LiAl1.5□0.5)[Al0.5Si3.5O10]F2. Voloshinite forms a continuous solid solution with lepidolite. According to X-ray single crystal study, voloshinite is monoclinic, space group C2/c. The unit-cell dimensions are: a = 5.191, b = 9.025, c = 20.40 Å, β = 95.37°, V= 951.5 Å3, Z = 4. Polytype is 2M 1. The strongest reflections in the X-ray powder diffraction pattern (d, Å-I[hkl]) are: 10.1-60[001]; 4.55-80[020, 110, 11$ \bar 1 $ \bar 1 ]; 3.49-50[11$ \bar 4 $ \bar 4 ]; 3.35-60[024, 006]; 3.02-45[025]; 2.575-100[11$ \bar 6 $ \bar 6 , 131, 20$ \bar 2 $ \bar 2 , 13$ \bar 4 $ \bar 4 ], 2.017-50[136, 0.0.10]. The mineral was named in honor of A.V. Voloshin (born in 1937), the famous Russian mineralogist. The type material is deposited at the Fersman Mineralogical Museum of the Russian Academy of Sciences, Moscow.
Geology of Ore Deposits, 2010
Geology of Ore Deposits, 2009
Geology of Ore Deposits, 2007
family were described for the first time only 40 years ago after the discovery of magadiite and k... more family were described for the first time only 40 years ago after the discovery of magadiite and kenyaite in the soda-bearing sediments of Lake Magadi, Kenya . A few years later, makatite and kanemite also found in the sediments of African soda lakes were described by and . Other findings in a similar environment showed that hydrous sodium silicates are characteristic of alkali carbonate supergene, foremost, the sedex-type mineral assemblages. Subsequently, the members of this family were described from a quite different setting. Makatite and new minerals-revdite and grumantite-were found in the salt mineralization of the late, low-temperature derivates of hyperalkaline igneous rocks in the Lovozero alkaline pluton, Kola Peninsula, Russia (Khomyakov et al.