scholarly journals The crystal structure of cesbronite, Cu3TeO4(OH)4: a novel sheet tellurate topology

2018 ◽  
Vol 74 (1) ◽  
pp. 24-31 ◽  
Author(s):  
O. P. Missen ◽  
S. J. Mills ◽  
M. D. Welch ◽  
J. Spratt ◽  
M. S. Rumsey ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Bond Valence ◽  
Chemical Formula ◽  
Charge Balance ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
International Mineralogical Association ◽  
Average Structure ◽  
Bond Valence Analysis

The crystal structure of cesbronite has been determined using single-crystal X-ray diffraction and supported by electron-microprobe analysis, powder diffraction and Raman spectroscopy. Cesbronite is orthorhombic, space group Cmcm, with a = 2.93172 (16), b = 11.8414 (6), c = 8.6047 (4) Å and V = 298.72 (3) Å3. The chemical formula of cesbronite has been revised to CuII 3TeVIO4(OH)4 from CuII 5(TeIVO3)2(OH)6·2H2O. This change has been accepted by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association, Proposal 17-C. The previously reported oxidation state of tellurium has been shown to be incorrect; the crystal structure, bond valence studies and charge balance clearly show tellurium to be hexavalent. The crystal structure of cesbronite is formed from corrugated sheets of edge-sharing CuO6 and (Cu0.5Te0.5)O6 octahedra. The structure determined here is an average structure that has underlying ordering of Cu and Te at one of the two metal sites, designated as M, which has an occupancy Cu0.5Te0.5. This averaging probably arises from an absence of correlation between adjacent polyhedral sheets, as there are two different hydrogen-bonding configurations linking sheets that are related by a ½a offset. Randomised stacking of these two configurations results in the superposition of Cu and Te and leads to the Cu0.5Te0.5 occupancy of the M site in the average structure. Bond-valence analysis is used to choose the most probable Cu/Te ordering scheme and also to identify protonation sites (OH). The chosen ordering scheme and its associated OH sites are shown to be consistent with the revised chemical formula.

The crystal-structure determination and redefinition of eztlite, Pb22+ Fe33+(Te4+O3)3(SO4)O2Cl

2018 ◽  
Vol 82 (6) ◽  
pp. 1355-1367 ◽  
Author(s):  
Owen P. Missen ◽  
Stuart J. Mills ◽  
John Spratt ◽  
Mark D. Welch ◽  
William D. Birch ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Mixed Valence ◽  
Lone Pair ◽  
Water Molecules ◽  
Monoclinic Space Group ◽  
Charge Balance ◽  
X Ray Diffraction ◽  
International Mineralogical Association ◽  
Bond Valence Analysis

ABSTRACTThe crystal structure of eztlite has been determined using single-crystal synchrotron X-ray diffraction and supported using electron microprobe analysis and powder diffraction. Eztlite, a secondary tellurium mineral from the Moctezuma mine, Mexico, is monoclinic, space group Cm, with a = 11.466(2) Å, b = 19.775(4) Å, c = 10.497(2) Å, β = 102.62(3)° and V = 2322.6(9) Å3. The chemical formula of eztlite has been revised to ${\rm Pb}_{\rm 2}^{2 +} {\rm Fe}_3^{3 +} $(Te4+O3)3(SO4)O2Cl from that stated previously as ${\rm Fe}_6^{3 +} {\rm Pb}_{\rm 2}^{2 +} $(Te4+O3)3(Te6+O6)(OH)10·nH2O. This change has been accepted by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association, Proposal 18-A. Eztlite was reported originally to be a mixed-valence Te oxysalt; however the crystal structure, bond-valence analysis and charge balance considerations clearly show that all Te is tetravalent. Eztlite contains a unique combination of elements and is only the second Te oxysalt to contain both sulfate and chloride. The crystal structure of eztlite contains mitridatite-like layers, with a repeating triangular nonameric [${\rm Fe}_9^{3 +} $O36]45– arrangement formed by nine edge-sharing Fe3+O6 octahedra, decorated by four trigonal pyramidal Te4+O3 groups, compared to PO4 or AsO4 tetrahedra in mitridatite-type minerals. In eztlite, all four tellurite groups associated with one nonamer are orientated with the lone pair of the Te atoms pointing in the same direction, whereas in mitridatite the central tetrahedron is orientated in the opposite direction to the others. In mitridatite-type structures, interlayer connections are formed exclusively via Ca2+ and water molecules, whereas the eztlite interlayer contains Pb2+, sulfate tetrahedra and Cl–. Interlayer connectivity in eztlite is achieved primarily by connections via the long bonds of Pbφ8 and Pbφ9 groups to sulfate tetrahedra and to Cl–. Secondary connectivity is via Te–O and Te–Cl bonds.

Structural, chemical and spectroscopic re-examination of type uklonskovite leads to its redefinition

2017 ◽  
Vol 81 (6) ◽  
pp. 1397-1404 ◽  
Author(s):  
S. Menchetti ◽  
L. Bindi ◽  
D. Belakovskiy ◽  
F. Zaccarini
Keyword(s):  
Crystal Structure ◽  
Scientific Literature ◽  
Careful Analysis ◽  
Chemical Formula ◽  
International Mineralogical Association ◽  
Mineralogical Association ◽  
Structural Details ◽  
First Time ◽  
Shed Light

AbstractThe crystal structure and the chemical composition of uklonskovite from the holotype material was reinvestigated to shed light on its correct chemical formula. On the basis of information gained from this characterization, we revised the formula from NaMg(SO4)OH·2H2O to NaMg(SO4)F·2H2O (F instead of OH). A careful analysis of the structural details together with a critical review of all the chemical data listed in the scientific literature for uklonskovite support our redefinition. We also present Raman data for the mineral for the first time. Our proposal was approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (voting proposal 16-J).

The crystal structure of comancheite, Hg2+55N3–24 (OH,NH2)4(Cl,Br)34, and crystal-chemical and spectroscopic discrimination of N3– and O2– anions in Hg2+ compounds

2013 ◽  
Vol 77 (8) ◽  
pp. 3217-3237 ◽  
Author(s):  
M. A. Cooper ◽  
Y. A. Abdu ◽  
F. C. Hawthorne ◽  
A. R. Kampf
Keyword(s):  
Crystal Structure ◽  
Three Dimensional ◽  
Direct Methods ◽  
Major Change ◽  
Orthorhombic Space Group ◽  
International Mineralogical Association ◽  
Mineralogical Association ◽  
Stretching Vibrations ◽  
Anion Species

AbstractThe crystal structure of comancheite, Hg2+55N3–24(OH, NH2)4(Cl,Br)34, orthorhombic, space group Pnnm, a = 18.414(5), b = 21.328(6), c = 6.6976(19) Å, V = 2630(2) Å3, Z = 1, was solved by direct methods and refined to an R1 index of 4.3% based on 4160 unique observed reflections. In the structure of comancheite, there are nine crystallographically distinct Hg2+ cations, each of which is coordinated by two N3– anions to form near-linear N3––Hg2+–N3– groups. Four other crystallographically distinct Hg2+ cations are coordinated by a mixture of N3–, O2–, (OH)– and (NH2)– anions, and there is a small amount of [Hg–Hg]2+ dimer. In addition, there are eight crystallographically distinct halogen sites, three of which are completely occupied by Cl–, and five of which are occupied by both Cl– and Br–. The principal anion, N3–, shows a strong preference for tetrahedral coordination by Hg2+, which results in a strongly bonded three-dimensional {–Hg2+–N3––} framework. This framework is both interrupted and contains large interstices that incorporate additional Hg2+ cations, a very small amount of [Hg+–Hg+]2+ dimer and additional anion species, O2–, (OH)– and (NH2)–, that coordinate Hg2+.Comancheite was described originally as an Hg-oxide mineral. The major change in chemical composition indicated by the present work was approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (Voting Proposal 13-B). The presence of N provides some analytical challenges, particularly in the presence of Hg. New bond-valence parameters were derived for Hg2+–N3– bonds [Ro(N3–) = 1.95] using well refined Hg2+ structures, and this allows discrimination between Hg2+–O2– and Hg2+–N3– bonds based on the valence-sum rule. Comparison of the Raman spectra of several Hg-bearing minerals shows that peaks in the range 500–700 cm–1 are characteristic of Hg2+–N3– stretching vibrations whereas peaks in the range 350–500 cm–1 are characteristic of Hg2+–O2– stretching vibrations; Hg2+–O2– and Hg2+ – N3– bonds may be discriminated on this basis.

scholarly journals Crystal structure of strontium perchlorate anhydrate, Sr(ClO4)2, from laboratory powder X-ray diffraction data

2019 ◽  
Vol 75 (4) ◽  
pp. 447-450
Author(s):  
Jooeun Hyoung ◽  
Hyeon Woo Lee ◽  
So Jin Kim ◽  
Hong Rim Shin ◽  
Seung-Tae Hong
Keyword(s):  
Crystal Structure ◽  
Diffraction Data ◽  
Bond Valence ◽  
Structure Model ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray ◽  
Wyckoff Position

The crystal structure of strontium perchlorate anhydrate, Sr(ClO4)2, was determined and refined from laboratory powder X-ray diffraction data. The material was obtained by dehydration of Sr(ClO4)2·3H2O at 523 K for two weeks. It crystallizes in the orthorhombic space group Pbca and is isotypic with Ca(AlD4)2 and Ca(ClO4)2. The asymmetric unit contains one Sr, two Cl and eight O sites, all on general positions (Wyckoff position 8c). The crystal structure consists of Sr2+ cations and isolated ClO4 − tetrahedra. The Sr2+ cation is coordinated by eight O atoms from eight ClO4 − tetrahedra. The validity of the crystal structure model for Sr(ClO4)2 anhydrate was confirmed by the bond valence method.

Polyhedral characteristics of the cosalite-type crystal structures

2019 ◽  
Vol 57 (5) ◽  
pp. 647-662
Author(s):  
Sabina Kovač ◽  
Predrag Dabić ◽  
Aleksandar Kremenović ◽  
Aleksandar Pačevski ◽  
Ljiiljana Karanović ◽  
...  
Keyword(s):  
Crystal Data ◽  
Chemical Formula ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
Area Detector ◽  
Octahedral Sites ◽  
Distorted Octahedral ◽  
Cation Substitutions ◽  
Type Crystal

Abstract The crystal structure of cosalite from the Trepča orefield was refined in the orthorhombic space group Pnma [a = 23.7878 (9), b = 4.0566 (3), c = 19.1026 (8) Å, V = 1843.35 (17) Å3, Z = 2] from single-crystal data (MoKα X-ray diffraction, CCD area detector) to the conventional R1 factor 0.031 for 1516 unique reflections with I > 2σ(I). The chemical formula (Cu0.15Ag0.24)+(Fe0.19Pb7.20)2+(Bi7.06Sb1.06)3+S20, calculated on the basis of 20 S atoms per formula unit, was determined by WDX. The unit cell contains 18 + 2 symmetrically nonequivalent atomic sites: 10 occupied by S; two by pure Pb (Pb3 and Pb4); one by pure Bi (Bi1); two by a combination of Bi and small amounts of Sb (Bi2/Sb2, Bi4/Sb3); two by Pb and Bi, and in one of these also by a small amount of Ag [Me1 = Pb2 >> Bi5 > Ag1, Me3 = Pb1 >> Bi3]; and finally one site, Me2 (Bi6 >> □), is partly occupied by Bi and partly split into an additional two adjacent trigonal planar “interstitial positions”, Cu1 and Cu2, where small amounts of Cu, Ag, and Fe can be situated. All atoms are at 4c special positions at y = 0.25 or 0.75. The structure consists of slightly to moderately distorted MeS6 octahedra sharing edges, bicapped trigonal PbS8 coordination prisms, and fairly distorted Cu1S6 and Cu2S4 polyhedra. The effects of the cation substitutions, bond valence sums, and the polyhedral characteristics are compared with other published cosalite-type structures. Among known cosalite-type structures, the largest volume contraction is shown by sample 4 (Altenberg) and involves the replacement of large cations (Bi3+ and Pb2+) by the smaller Sb3+, as well as Cu+ and Ag+. These replacements are reflected in the variations of individual Me–S bond distances, which are accompanied by variations in average Me–S distances. The degree of polyhedral distortion, Δ, progressively increases for the four Bi-hosting sites of nine cosalite-type structures: Me2 < Bi2 < Bi1 < Bi4. The Bi4 and Me3 are the most and the Me1 and Me2 are the least distorted octahedral sites of the nine cosalite-type structures.

scholarly journals β-Y(BO2)3 – a new member of the β-Ln(BO2)3 (Ln=Nd, Sm, Gd–Lu) structure family

2017 ◽  
Vol 72 (12) ◽  
pp. 983-988 ◽  
Author(s):  
Martin K. Schmitt ◽  
Hubert Huppertz
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Lattice Parameters ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray

Abstractβ-Y(BO2)3 was synthesized in a Walker-type multianvil module at 5.9 GPa/1000°C. The crystal structure has been elucidated through single-crystal X-ray diffraction. β-Y(BO2)3 crystallizes in the orthorhombic space group Pnma (no. 62) with the lattice parameters a=15.886(2), b=7.3860(6), and c=12.2119(9) Å. Its crystal structure will be discussed in the context of the isotypic lanthanide borates β-Ln(BO2)3 (Ln=Nd, Sm, Gd–Lu).

Crystal structure characterization and electronic structure of a rare-earth-containing Zintl phase in the Yb–Al–Sb family: Yb3AlSb3

2021 ◽  
Vol 77 (6) ◽  
Author(s):  
Rongqing Shang ◽  
An T. Nguyen ◽  
Allan He ◽  
Susan M. Kauzlarich
Keyword(s):  
Crystal Structure ◽  
Electronic Structure ◽  
Rare Earth ◽  
Electronic Structure Calculations ◽  
Structure Characterization ◽  
Charge Balance ◽  
X Ray Diffraction ◽  
Zintl Phase ◽  
X Ray ◽  
Structure Calculations

A rare-earth-containing compound, ytterbium aluminium antimonide, Yb3AlSb3 (Ca3AlAs3-type structure), has been successfully synthesized within the Yb–Al–Sb system through flux methods. According to the Zintl formalism, this structure is nominally made up of (Yb2+)3[(Al1−)(1b – Sb2−)2(2b – Sb1−)], where 1b and 2b indicate 1-bonded and 2-bonded, respectively, and Al is treated as part of the covalent anionic network. The crystal structure features infinite corner-sharing AlSb4 tetrahedra, [AlSb2Sb2/2]6−, with Yb2+ cations residing between the tetrahedra to provide charge balance. Herein, the synthetic conditions, the crystal structure determined from single-crystal X-ray diffraction data, and electronic structure calculations are reported.

Kenoplumbomicrolite, (Pb,□)2Ta2O6[□,(OH),O], a new mineral from Ploskaya, Kola Peninsula, Russia

2018 ◽  
Vol 82 (5) ◽  
pp. 1049-1055 ◽  
Author(s):  
Daniel Atencio ◽  
Marcelo B. Andrade ◽  
Luca Bindi ◽  
Paola Bonazzi ◽  
Matteo Zoppi ◽  
...  
Keyword(s):  
Kola Peninsula ◽  
Northern Region ◽  
Complete Characterization ◽  
New Mineral ◽  
X Ray Diffraction ◽  
International Mineralogical Association ◽  
Cell Parameters ◽  
Mohs Hardness

ABSTRACTThis study presents a complete characterization of kenoplumbomicrolite, (Pb,□)2Ta2O6[□,(OH),O], occurring in an amazonite pegmatite from Ploskaya Mountain, Western Keivy Massif, Kola Peninsula, Murmanskaja Oblast, Northern Region, Russia.Kenoplumbomicrolite occurs in yellowish brown octahedral, cuboctahedral and massive crystals, up to 20 cm, has a white streak, a greasy lustre and is translucent. The Mohs hardness is ~6. Attempts to measure density (7.310–7.832 g/cm3) were affected by the ubiquitous presence of uraninite inclusions. Reflectance values were measured in air and immersed in oil. Kenoplumbocrolite is optically isotropic. The empirical formula is (Pb1.30□0.30Ca0.29Na0.08U0.03)Σ2.00(Ta0.82Nb0.62Si0.23Sn4+0.15Ti0.07Fe3+0.10Al0.01)Σ2.00O6[□0.52(OH)0.25O0.23]Σ1.00 (from the crystal used for the structural study) and (Pb1.33□0.66Mn0.01)Σ2.00(Ta0.87Nb0.72Sn4+0.18Fe3+0.11W0.08Ti0.04)Σ2.00O6[□0.80(OH)0.10O0.10]Σ1.00 (average including additional fragments). The mineral is cubic, space group Fd$\overline 3 $m. The unit-cell parameters refined from powder X-ray diffraction data are a = 10.575(2) Å and V = 1182.6(8) Å3, which are in accord with those obtained previously from a single crystal of a = 10.571(1) Å, V = 1181.3(2) Å3 and Z = 8. The mineral description and its name have been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (IMA2015-007a).

The molecular and crystal structure of [Pt(diethylenetriamine)(guanosine)](ClO4)2

1979 ◽  
Vol 57 (1) ◽  
pp. 57-61 ◽  
Author(s):  
R. Melanson ◽  
F. D. Rochon
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Least Squares ◽  
Platinum Atom ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
R Factor ◽  
Square Planar ◽  
Coordination Plane

The crystal structure of [Pt(diethylenetriamine)(guanosine)](ClO4)2 has been determined by X-ray diffraction. The crystals are orthorhombic, space group P212121, with a = 12.486(6), b = 13.444(7), c = 14.678(11) Å, and Z = 4. The structure was refined by block-diagonal least-squares analysis to a conventional R factor of 0.050 and a weighted Rw = 0.045.The coordination around the platinum atom is square planar. Guanosine is bonded to platinum through N(7). The purine planar ring makes an angle of 62.7° with the platinum coordination plane. The structure is stabilized by hydrogen bonding.

Determination of the Crystal Structure and Redefinition of Tsugaruite, Pb28As15S50Cl, the First Lead-Arsenic Chloro-Sulfosalt

2020 ◽  
Author(s):  
Cristian Biagioni ◽  
Luca Bindi ◽  
Koichi Momma ◽  
Ritsuro Miyawaki ◽  
Yoshitaka Matsushita ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Atomic Ratio ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Specific Position ◽  
Actual Classification ◽  
Aomori Prefecture

Abstract Tsugaruite was originally defined as a lead-arsenic sulfosalt from the Yunosawa mine, Aomori Prefecture, Japan. Until recently its crystal structure remained unsolved and its actual classification in the sulfosalt realm was unknown. Here the refinement of the crystal structure of tsugaruite using single-crystal X-ray diffraction data is reported. The mineral is orthorhombic, space group P2nn, with unit-cell parameters a = 8.0774(10), b = 15.1772(16), c = 38.129(4) Å, V = 4674.3(9) Å3, in agreement with previous studies. The solution of the crystal structure of this mineral revealed Cl occupying a specific position. Chlorine was thus sought and found using the electron microprobe; the average of six spot analyses gave (in wt.%): Pb 68.04, As 12.83, S 18.29, Cl 0.63, total 99.80. The empirical formula, calculated on the basis of Pb + As = 43 atoms per formula unit, is Pb28.26As14.74S49.08Cl1.52. Tsugaruite is an N = 4 plesiotypic derivative of the homologous series of Pb-Sb chloro-sulfosalts having the general formula Pb(2+2N)(Sb,Pb)(2+2N)S(2+2N)(S,Cl)(4+2N)ClN. It has a Cl/(Cl + S) atomic ratio close to that of other known Pb-Sb chloro-sulfosalts (pillaite, pellouxite) and slightly higher than that of dadsonite.

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