Ferri-obertiite from the Rothenberg quarry, Eifel volcanic complex, Germany: mineral data and crystal chemistry of a new amphibole end-member

2017 ◽  
Vol 81 (3) ◽  
pp. 641-651 ◽  
Author(s):  
Roberta Oberti ◽  
Massimo Boiocchi ◽  
Frank C. Hawthorne ◽  
Neil A. Ball ◽  
Günter Blass
Keyword(s):  
Structure Refinement ◽  
Volcanic Complex ◽  
X Ray ◽  
International Mineralogical Association ◽  
Holotype Specimen ◽  
Cell Dimensions ◽  
Mineral Data ◽  
Unit Cell Dimensions ◽  
The Ideal

AbstractPink-orange crystals of a composition within the ferri-obertiite compositional space were found in vesicles in a pale beige silicate vein found from a basalt quarry at Mount Rothenberg, Eifel district, Germany. Associated minerals are potassic feldspar, alpha quartz paramorphic afterbeta quartz, eifelite (the second occurrence after the Caspar quarry at Bellerberg volcano, Eifel region), tridymite, rutile, roedderite and other amphiboles. The ideal formula of ferri-obertiite is ANaBNa2C(Mg3Fe3+Ti)TSi8O22WO2; the empirical formula derived for the holotype specimen from Mount Rothenberg from the results of electron-microprobe analysis and single-crystal structure refinement is A(Na0.76K0.22)∑0.98B(Na1.61Ca0.35Mn0.042+)∑2.00C(Mg3.58Mn0.112+Fe0.623+Ti0.664+Cr0.013+Zn0.01Ni0.01)∑5.00T(Si7.82Ti0.124+Al0.06)∑8.00O22W[O1.26F0.55(OH)0.19]∑2.00. The unit-cell dimensions are a = 9.7901(7), b = 17.9354(13), c = 5.2892(4)Å, β= 104.142(2)°, V = 900.58 (11) Å3. The space group is C2/m, Z = 2. Ferri-obertiite is biaxial (+), with α = 1.664, β = 1.680, γ = 1.722, all ±0.002 and 2V (meas.) = 66.4(3)o, 2V (calc.) = 64.7o.The strongest eight reflections in the powder X-ray pattern [d values (in Å), I, (hkl)] are: 2.704, 100, (151); 3.116, 76, (310); 3.388, 72, (131); 8.931, 72, (110); 2.529, 67, (202); 2.583, 39, (061); 2.160, 38, (261); 3.260, 37, (240). Both the mineral and thename have been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (IMA 2015-079); the rock specimen has been deposited at the Museo di Mineralogia, Dipartimento di Scienze della Terra e dell'Ambiente, Universitàdegli Studi di Pavia, under the code 2015-02.

Fluoro-tremolite from the Limecrest-Southdown quarry, Sparta, New Jersey, USA: crystal chemistry of a newly approved end-member of the amphibole supergroup

2018 ◽  
Vol 82 (1) ◽  
pp. 145-157
Author(s):  
Roberta Oberti ◽  
Fernando Cámara ◽  
Fabio Bellatreccia ◽  
Francesco Radica ◽  
Antonio Gianfagna ◽  
...  
Keyword(s):  
New Jersey ◽  
Structure Refinement ◽  
X Ray ◽  
International Mineralogical Association ◽  
Holotype Specimen ◽  
Cell Dimensions ◽  
Unit Cell Dimensions ◽  
The Ideal

ABSTRACTDuring systematic characterization of amphiboles that still lack a complete mineral description, fluoro-tremolite was identified in a specimen from the Limecrest-Southdown quarry, Sparta, New Jersey, USA, which was provided by the Franklin Mineral Museum. The ideal formula of fluoro-tremolite is A□ BCa2CMg5TSi8O22WF2 and the empirical formula derived for the holotype specimen, based on the results of electron-microprobe analysis and single-crystal structure refinement, is A(Na0.28K0.02)Σ0.30B(Ca1.99Na0.01)Σ2.00C(Mg4.70${\rm Fe}_{{\rm 0}{\rm. 28}}^{{\rm 2 +}} $Zn0.01${\rm Ti}_{{\rm 0}{\rm. 01}}^{{\rm 4 +}} $)Σ5.00T(Si7.68Al0.32)Σ8.00O22W(F1.16OH0.84)Σ2.00. The unit-cell dimensions in space group C2/m are a = 9.846(2), b = 18.050(3), c = 5.2769(14) Å, β = 104.80(2)° and V = 906.7 (3) Å3 and Z = 2; the a:b:c ratio is 0.545:1:0.292. Fluoro-tremolite is biaxial (+), with α = 1.5987(5), β = 1.6102(5), γ = 1.6257(5), 2V(meas.) = 85(1)o and 2V(calc.) = 82o. The strongest ten reflections in the powder X-ray pattern [d values (in Å), I, (hkl)] are: 2.706, 100, (151); 3.126, 67, (310); 2.531, 59, ($\bar 2$02); 3.381, 57, (131); 2.940, 43, ($\bar 1$51, 221); 3.276, 37, (240); 2.337, 36, ($\bar 3$51); 2.592, 35, (061); 2.731, 34, ($\bar 3$31); 2.163, 34, (261). Both the mineral and the mineral name have been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (IMA2016–018); the holotype has been deposited at the Franklin Mineral Museum (32 Evans Street, Franklin, 07416 New Jersey, US), under the catalogue number 7710.Comparison with new data on tremolite and synthetic fluoro-tremolite provides a more sound crystal-chemical model of the end-member compositions and their solid-solution.

Magnesio-arfvedsonite from Jade Mine Tract, Myanmar: mineral description and crystal chemistry

2015 ◽  
Vol 79 (2) ◽  
pp. 253-260 ◽  
Author(s):  
Roberta Oberti ◽  
Massimo Boiocchi ◽  
Frank C. Hawthorne ◽  
Neil A. Ball ◽  
George E. Harlow
Keyword(s):  
Crystal Structure ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Structure Refinement ◽  
Crystal Structure Refinement ◽  
American Museum ◽  
X Ray ◽  
Cell Dimensions ◽  
Unit Cell Dimensions ◽  
The Ideal

AbstractMagnesio-arfvedsonite, theCFe3+-dominant analogue of eckermannite, has been found in a sample of “szechenyite” in the mineral collection of the American Museum of Natural History (AMNH H35024). It comes from the northern part of the Jade Mine Tract near Hpakan, Kachin State, Myanmar. Associated minerals are kosmochlor–jadeite solid-solution pyroxene and clinochlore. The ideal formula of magnesio-arfvedsonite isANaBNa2C(Mg4Fe3+)TSi8O22W(OH)2, and the empirical formula derived from electron microprobe analysis and single-crystal structure refinement for the sample of this work isA(Na0.96K0.04)Σ=1.00B(Na1.57Ca0.40Fe0.022+Mn0.01)Σ=2.00C(Mg4.26Fe0.192+Fe0.413+Al0.11Ti0.034+)Σ=5.00T(Si7.99Al0.01)Σ=8.00O22W[F0.02(OH)1.98]Σ=2.00. The unit-cell dimensions area= 9.867(1),b= 17.928(2),c= 5.284(1) Å, β = 103.80(2)°,V= 907.7 (2) Å3,Z= 2. Magnesio-arfvedsonite is biaxial (–), with α = 1.624, β = 1.636, γ = 1.637, all ± 0.002 and 2Vobs= 36(1)°, 2Vcalc= 32°. The ten strongest reflections in the X-ray powder pattern [dvalues (in Å),I, (hkl)] are: 2.708, 100, (151); 3.399, 68, (131); 3.144, 63, (310); 2.526, 60, (202); 8.451, 46, (110); 3.273, 39, (240); 2.167, 37, (261); 2.582, 34, (061); 2.970, 34, (221); 2.326, 33, [(251) (421)].

Structure Determination of Al2CuMg Precipitates in Al-Cu-Mg Alloys by Structure Refinement and Quantitative Image Comparison

2000 ◽  
Vol 6 (S2) ◽  
pp. 1030-1031
Author(s):  
R. Kilaas ◽  
V. Radmilovic
Keyword(s):  
Structure Refinement ◽  
Metallic Phase ◽  
S Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Low Weight ◽  
Cell Dimensions ◽  
Quantitative Image ◽  
Unit Cell Dimensions

Al-Cu-Mg based alloys are of significant interest for aerospace and other applications, due to their low weight, mechanical strength and corrosion resistance. Their mechanical properties are based on a dispersion of S-phase precipitates, which have the composition Al2CuMg. The crystal structure of this inter-metallic phase has been studied using different diffraction techniques for more than five decades. While several models have been proposed for the structure of S-phase[l], only one of the previously proposed models were found to give a reasonable fit to our experimental data. This model, shown in Fig. 1 and given by Perlitz and Westgren (PW) [2] based on X-ray diffraction data, is orthorhombic with unit cell dimensions a = 0:4 nm, b = 0.923 nm, and c = 0.714 nm, space group Cmcm, containing 16 atoms in the ratio Al:Cu:Mg = 2:1:1.Several HREM images of S-phase precipitates located near the edge of the foil, Fig. 2, recorded along the [100]s and [010]s directions, were digitized from film and used for analysis.

Redefinition of thérèsemagnanite, NaCo4(SO4)(OH)6Cl·6H2O: new data and relationship to ‘cobaltogordaite’

2018 ◽  
Vol 82 (1) ◽  
pp. 159-170 ◽  
Author(s):  
Anatoly V. Kasatkin ◽  
Jakub Plášil ◽  
Radek Škoda ◽  
Dmitriy I. Belakovskiy ◽  
Joe Marty ◽  
...  
Keyword(s):  
Crystal Structure Data ◽  
New Mineral ◽  
X Ray Diffraction ◽  
Oh Groups ◽  
X Ray ◽  
International Mineralogical Association ◽  
Mineralogical Association ◽  
Holotype Specimen ◽  
Cl Atoms ◽  
The Ideal

ABSTRACTThérèsemagnanite was originally described from the Cap Garonne mine, Var, France. Its ideal formula was reported as (Co,Zn,Ni)6(SO4)(OH,Cl)10·8H2O; without crystal structure data, only the powder X-ray diffraction pattern was given. Revision of the holotype material revealed that thérèsemagnanite is identical to ‘cobaltogordaite’ (IMA2014-043), recently described from the Blue Lizard mine, Utah, USA. Thérèsemagnanite is thus redefined in accordance with the new data obtained for the neotype specimen from Blue Lizard (formerly the holotype specimen of ‘cobaltogordaite’) and ‘cobaltogordaite’ has been discredited by the International Mineralogical Association Commission on New Mineral Nomenclature and Classification (IMA CNMNC). Thérèsemagnanite has the ideal, end-member formula NaCo4(SO4)(OH)6Cl·6H2O. The empirical formulae of the holotype (Cap Garonne) and the neotype (Blue Lizard), both based on microprobe analyses and calculated on the basis of 17 O + Cl atoms per formula unit (with fixed 6 OH groups and 6 H2O molecules; H content is calculated by stoichiometry) are (Na0.64K0.09)Σ0.73(Co2.35Zn1.22Ni0.50)Σ4.07S1.02O3.98(OH)6Cl1.02·6H2O and Na1.01(Co1.90Zn1.37Ni0.48Cu0.15Mn0.05)Σ3.95S1.03O4.09(OH)6Cl0.91·6H2O, respectively. Thérèsemagnanite is trigonal,P$\overline 3 $,a= 8.349(3),c= 13.031(2) Å,V= 786.6(4) Å3and Z = 2 (neotype). The strongest powder X-ray diffraction lines are [dobsin Å (hkl) (Irel)]: 13.10 (001)(100), 6.53 (002)(8), 4.173 (110)(4), 3.517 (112)(5), 2.975 (104, 10$\overline 4 $)(4), 2.676 (211)(5) and 2.520 (12$\bar 2$)(5) (neotype). Thérèsemagnanite is a cobalt analogue of gordaite, NaZn4(SO4)(OH)6Cl·6H2O. These minerals represent the gordaite group, accepted by the IMA CNMNC.

A hydrated barium-strontium pyrochlore in a biotite rock from Panda Hill, Tanganyika

1959 ◽  
Vol 32 (244) ◽  
pp. 10-25 ◽  
Author(s):  
E. Jäger ◽  
E. Niggli ◽  
A. H. Van der Veen
Keyword(s):  
Pyrochlore Structure ◽  
Exchange Capacity ◽  
New Mineral ◽  
Hydroxyl Groups ◽  
X Ray Diffraction ◽  
X Ray ◽  
Barium Strontium ◽  
Cell Dimensions ◽  
Unit Cell Dimensions ◽  
The Ideal

SummaryA hydrated barium-strontium pyrochlore with only subordinate amounts of Ca and Na has been found in a weathered biotite rock (contact-rock of a carbonatite) from Panda Hill, Tanganyika, as small euhedral yellowish-grey cubic crystals (showing the combination of the octahedron and the cube) in a rock containing euhedral biotite, some orthoclase, and several other minerals. Hydrated Ba-Sr pyrochlore is isotropic, the refractive index varies from 2·07 to 2·10. The reflectivity (vertical illumination) is 13·2 %. H. Poor {111} cleavage. The pyrochlore structure (space-group O7h–Fd3m) and the unit-cell dimensions (a 10·562 Å.) are derived from X-ray powder and Weissenberg photographs. The calculated specific gravity is 4·01 (observed, 4·00 on dried material). Chemical analysis gives BaO 12·5, SrO 6·4, Na2O 0·28, K2O 0·25, CaO 1·35, rare earths (mainly Ce2O3) 2, ThO2 0·6, FeO 0·45, TiO2 3·9, Nb2O5 67·0, Ta2O5 0·22, H2O+ 4·0, other constituents 2·21, total 101·16. After deduction for impurities the following formula resulted: (Ba0·30Sr0·22Ca0·05Ce0·04Na0·03Fe0·02K0·01Th0·01)(Nb1·83Ta0·004Ti0·17)O5·61(H2O)0·80.The ideal formula for pyrochlore is A2B2O6(F,OH). In the mineral described only a third of the A-positions are occupied by Ba, Sr, etc. Infra-red spectrophotometry does not indicate hydroxyl-groups. When the mineral is treated with TINO3 solution the intensities of the X-ray diffraction lines 333/511, and 444 are changed; hydrated Ba-Sr pyrochlore shows a certain exchange-capacity.The name pandaite, from Panda Hill, is proposed for the new mineral.

scholarly journals Potassic-Hastingsite from the Kedrovy District (East Siberia, Russia): Petrographic Description, Crystal Chemistry, Spectroscopy, and Thermal Behavior

Minerals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1049
Author(s):  
Ekaterina Kaneva ◽  
Tatiana Radomskaya ◽  
Roman Shendrik ◽  
Victor Chubarov ◽  
Victoria Danilovsky
Keyword(s):  
Thermal Expansion ◽  
High Temperature ◽  
Structure Refinement ◽  
Fluorescence Analysis ◽  
Unit Cell ◽  
East Siberia ◽  
X Ray ◽  
Cell Dimensions ◽  
Dark Green ◽  
Unit Cell Dimensions

In this work we report on a petrographic, crystal-chemical, and optical characterization, obtained from different analytical methods, of amphibole species. Potassic-hastingsite, ideally AKBCa2C(Fe2+4Fe3+)T(Si6Al2)O22W(OH)2, has been found in the Kedrovy district (East Siberia, Russia). The sample occurs as well-formed and large radially radiant aggregates of dark green, almost black crystals. The unit cell dimensions are a = 9.9724(3) Å, b = 18.2968(4) Å, c = 5.3573(1) Å, β = 104.945(3)°, V = 944.44(4) Å3, Z = 2. Site populations were determined by combining single-crystal structure refinement and electron probe microanalysis, and Fe3+/Fe2+ ratio was obtained from X-ray fluorescence analysis. Infrared, diffuse light UV/Vis/NIR absorption, and electron spin resonance spectra are presented and discussed. A thermoelastic behavior of a powder of potassic-hastingsite was studied by in situ high-temperature X-ray diffraction. A thermal expansion and subsequent significant contraction in the unit cell volume during a high-temperature X-ray powder diffraction experiment is observed as a consequence of the deprotonation process, which is locally balanced via oxidation of Fe2+. According to the data obtained for potassic-hastingsite, these processes occur within 400–600 °C. The thermal expansion of the mineral is anisotropic; the thermal expansivity coefficients αa: αb: αc (×10−6) = −18.06 : 9.59 : −1.09 at 400 °C, −26.15 : −1.52 : 2.22 at 600 °C and 23.77 : −25.06 : 42.08 at 750 °C.

Oxo-mangani-leakeite from the Hoskins mine, New South Wales, Australia: occurrence and mineral description

2016 ◽  
Vol 80 (6) ◽  
pp. 1013-1021 ◽  
Author(s):  
Roberta Oberti ◽  
Massimo Boiocchi ◽  
Frank C. Hawthorne ◽  
Neil A. Ball ◽  
Paul M. Ashley
Keyword(s):  
Microprobe Analysis ◽  
New South ◽  
Structure Refinement ◽  
New South Wales ◽  
Ion Microprobe ◽  
X Ray ◽  
South Wales ◽  
Cell Dimensions ◽  
D Values ◽  
Unit Cell Dimensions

AbstractOxo-mangano-leakeite, a newly approved end-member of the amphibole supergroup (IMA-CNMNC 20150-35), has been found in a rock containing manganese silicate and oxide at the Hoskins Mine, a Mn deposit 3 km west of Grenfell, New South Wales. The end-member formula of oxo-mangani-leakeite is ANaBNa2C(Mn3+4Li)TSi8 O22WO2, which would require SiO2 53.15, Mn2O3 34.91, Li2O 1.66, Na2O 10.28, total 100.00 wt.%. The empirical formula derived for the sample of this work from electron and ion microprobe analysis using constraints resulting from single-crystal structure refinement is A(Na0.65K0.36)∑ = 1.01B(Na1.94Ca0.06)∑ = 2.00C(Mg1.60Zn0.01 Li0.58)∑ = 5.01T(Si7.98Al0.02)∑ = 8.00O22W(O1.34OH0.66)∑ = 2.00. Oxo-mangano-leakeite is biaxial (–), with α = 1.681, β = 1.712, γ = 1.738, all ± 0.002, and 2V (meas.) = 81.0(4)°, 2V (calc.) = 83.5°. The unit-cell dimensions are a = 9.875(5), b = 17.873(9), c = 5.295(2) Å, β = 104.74(3)°, V = 903.8 (7) Å3; the space group is C2/m, with Z = 2. The strongest ten reflections in the powder X-ray pattern [d values (in Å), I, (hkl)] are: 8.423, 100, (110); 3.377, 46, (131); 4.461, 40, (040); 4.451, 40, (021); 3.134, 37, (); 2.694, 37, (151); 2.282, 27, (); 2.734, 25, (3̅31); 2.575, 24, (061); 2.331, 24, [() ()]. The holotype material is deposited in the Canadian Museum of Nature, Ottawa, under the catalogue number CMNMC 86895.

‘Clinobarylite’–barylite: order-disorder relationships and nomenclature

2015 ◽  
Vol 79 (1) ◽  
pp. 145-155 ◽  
Author(s):  
Stefano Merlino ◽  
Cristian Biagioni ◽  
Elena Bonaccorsi ◽  
Nikita V. Chukanov ◽  
Igor V. Pekov ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Unit Cell ◽  
Group Symmetry ◽  
Orthorhombic Symmetry ◽  
Space Group ◽  
International Mineralogical Association ◽  
Cell Parameters ◽  
Holotype Specimen ◽  
Cell Dimensions ◽  
Unit Cell Dimensions

Abstract'Clinobarylite', BaBe2Si2O7, was defined as a monoclinic dimorph of orthorhombic barylite. Subsequently, its crystal structure was also proved to be orthorhombic, differing from barylite in terms of the space group symmetry, Pmn21 instead of Pmnb, and in unit-cell dimensions. Through the order-disorder (OD) theory, the polytypic relationships between 'clinobarylite' and barylite are described. 'Clinobarylite' corresponds to the MDO1 polytype, with unit-cell parameters a = 11.650, b = 4.922, c = 4.674 Å, space group Pmn21; barylite corresponds to the MDO2 polytype, with a = 11.67, b = 9.82, c = 4.69 Å, space group Pmnb. The re-examination of the holotype specimen of 'clinobarylite' confirmed its orthorhombic symmetry. Its crystal structure has been refined starting from the atomic coordinates calculated for the MDO1 polytype and the refinement converged to R1 = 0.0144 for 929 observed reflections [Fo > 4σFo]. Owing to their polytypic relationships, 'clinobarylite' and barylite should be conveniently indicated as barylite-1O and barylite-2O, respectively; the name 'clinobarylite' should be discontinued. This new nomenclature of the barylite polytypes has been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (IMA 13-E).

Baghdadite, a new calcium zirconium silicate mineral from Iraq

1986 ◽  
Vol 50 (355) ◽  
pp. 119-123 ◽  
Author(s):  
H. M. Al-Hermezi ◽  
D. McKie ◽  
A. J. Hall
Keyword(s):  
Crystal Habit ◽  
Silicate Mineral ◽  
Calculated Density ◽  
X Ray ◽  
Zirconium Silicate ◽  
Cell Dimensions ◽  
Single Crystal Study ◽  
Optic Orientation ◽  
Unit Cell Dimensions ◽  
The Ideal

AbstractBaghdadite, a new calcium zirconium silicate mineral has been found in melilite skarn in contact with banded diorite, from the Qala-Dizeh region, NE Iraq. Electron microprobe analysis yielded: SiO2 = 29.26, ZrO2 = 27.00, TiO2 = 2.11, Fe2O3 = 0.11, Al2O3 = 0.03, MgO = 0.05, CaO = 41.44, Na2O = 0.02, sum = 100.02 wt. %. The mineral contains about 0.16% HfO2. This analysis calculates to Ca3.00(Zr0.89Ti0.11)(Si1.98Fe0.01)O9 which leads to the ideal formula Ca3Zr[O2|Si2O7]. X-ray single crystal study showed it to be monoclinic with space group P21/a. The unit cell dimensions are: a = 10.42(2), b = 10.16(2), c = 7.36(1) Å, β = 91.1°, Z = 4 and cell volume = 779.04 Å3. The seven strongest lines in the powder diffraction pattern are (d,I,hkl): 7.30 (45)(110), 3.23 (80)(130), 3.04 (75)(2̄02), 2.98 (85)(202), 2.88 (70)(320,212), 2.84 (100)(230), 1.702 (40)(522). It is colourless, lustre vitreous, no cleavage and VHN50 = 725–783 kg mm−2 with H ∼ 6. Calculated density = 3.48 g cm−3 which is very close to 3.46 measured density of a synthetic Ca3ZrSi2O9. It is optically biaxial, positive, 2 V ∼ 72°, dispersion indiscernible. The cathodoluminescence colour is dull grey with a greenish tint. Refractive indices: α= 1.652, β = 1.658, γ = 1.670. The crystal habit is stumpy prismatic and a contact twin with b as twinning axis is observed. Optic orientation: α = c, β//b, γ = a.

scholarly journals Crystal structure of uranyl-oxide mineral wölsendorfite revisited

2020 ◽  
Vol 28 (2) ◽  
pp. 322-330
Author(s):  
Jakub Plášil
Keyword(s):  
Crystal Structure ◽  
Structure Refinement ◽  
Complex Structure ◽  
Structural Formula ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
Oxide Mineral ◽  
Cell Dimensions ◽  
Unit Cell Dimensions

The crystal structure of the rare supergene Pb2+-containing uranyl-oxide mineral wölsendorfite has been revisited employing the single-crystal X-ray diffraction. The new structure refinement provided deeper insight into the complex structure of this mineral, revealing additional H2O sites in the interlayer complex and confirming the entrance of the Ca2+ into the structure. Studied wölsendorfite is orthorhombic, space group Cmcm, with unit cell dimensions a = 14.1233(8) Å, b = 13.8196(9) Å, c = 55.7953(12) Å, V = 10890.0(10) Å3, and Z = 8. The structure has been refined to an agreement index (R) of 10.74% for 3815 reflections with I > 3σ(I) collected using a microfocus X-ray source from the microcrystal. In line with the previous structure determination, the refined structure contains U–O–OH sheets of the wölsendorfite topology and an interstitial complex comprising nine symmetrically unique Pb sites, occupied dominantly by Pb2+. Nevertheless, one of the sites seems to be plausible for hosting Ca2+. Its presence has been successfully modeled by the refinement and further supported by the crystal-chemical considerations. The structural formula of wölsendorfite crystal studied is Pb6.07Ca0.68[(UO2)14O18(OH)5]O0.5(H2O)12.6, with Z = 8, Dcalc. = 6.919 g·cm–3 (including theoretical 30.2 H atoms). The rather complex structure of wölsendorfite makes it the third most complex known uranyl-oxide hydroxy-hydrate mineral.

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