scholarly journals Structural Trends and Solid-Solutions Based on the Crystal Chemistry of Two Hausmannite (Mn3O4) Samples from the Kalahari Manganese Field

Minerals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 343 ◽  
Author(s):  
Sytle M. Antao ◽  
Laura A. Cruickshank ◽  
Kaveer S. Hazrah
Keyword(s):  
Single Crystal ◽  
Crystal Chemistry ◽  
Structure Refinement ◽  
Site Occupancy ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Jahn Teller

The crystal chemistry of two hausmannite samples from the Kalahari manganese field (KMF), South Africa, was studied using electron-probe microanalysis (EPMA), single-crystal X-ray diffraction (SCXRD) for sample-a, and high-resolution powder X-ray diffraction (HRPXRD) for sample-b, and a synthetic Mn3O4 (97% purity) sample-c as a reference point. Hausmannite samples from the KMF were reported to be either magnetic or non-magnetic with a general formula AB2O4. The EPMA composition for sample-a is [Mn2+0.88Mg2+0.11Fe2+0.01]Σ1.00Mn3+2.00O4 compared to Mn2+Mn3+2O4 obtained by refinement. The single-crystal structure refinement in the tetragonal space group I41/amd gave R1 = 0.0215 for 669 independently observed reflections. The unit-cell parameters are a = b = 5.7556(6), c = 9.443(1) Å, and V = 312.80(7) Å3. The Jahn–Teller elongated Mn3+O6 octahedron of the M site consists of M–O × 4 = 1.9272(5), M–O × 2 = 2.2843(7), and an average <M–O>[6] = 2.0462(2) Å, whereas the Mn2+O4 tetrahedron of the T site has T–O × 4 = 2.0367(8) Å. The site occupancy factors (sof) are M(sof) = 1.0 Mn (fixed, thereafter) and T(sof) = 1.0008(2) Mn. The EPMA composition for sample-b is [Mn0.99Mg0.01](Mn1.52Fe0.48)O4. The Rietveld refinement gave R (F2) = 0.0368. The unit-cell parameters are a = b = 5.78144(1), c = 9.38346(3) Å, and V = 313.642(1) Å3. The octahedron has M–O × 4 = 1.9364(3), M–O × 2 = 2.2595(6), and average <M–O>[6] = 2.0441(2) Å, whereas T–O × 4 = 2.0438(5) Å. The refinement gave T(sof) = 0.820(9) Mn2+ + 0.180(9) Fe2+ and M(sof) = 0.940(5) Mn3+ + 0.060(5) Fe3+. Samples-a and -b are normal spinels with different amounts of substitutions at the M and T sites. The Jahn–Teller elongation, Δ(M–O), is smaller in sample-b because atom substitutions relieve strain compared to pure Mn3O4.

Molecular and crystal structure of a copper(II) complex of sildenafil

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Akhmatkhodja N. Yunuskhodjayev ◽  
Shokhista F. Iskandarova ◽  
Vahobjon Kh. Sabirov
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Unit Cell ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Piperazine Ring ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters

Abstract The crystal structure of a copper(II) complex of protonated sildenafil, CuCl3C22H31N6O4S⋅2H2O was studied by single crystal X-ray diffraction. The compound crystallizes in the monoclinic space group P21/n with the unit cell parameters a = 15.4292(2), b = 9.06735(12), c = 21.1752(2) Å, V = 2945.48(7) Å3, Z = 4. The Cu atom is coordinated by the sildenafil ligand via the N2 atom of the pyrazolopyrimidine ring and by three chloride anions. Sildenafil is protonated at the methylated N6 atom of the piperazine ring and it is cation ligand with a 1+ charge.

A new mineral, zincolibethenite, CuZnPO4OH, a stoichiometric species of specific site occupancy

2005 ◽  
Vol 69 (2) ◽  
pp. 145-153 ◽  
Author(s):  
R. S. W. Braithwaite ◽  
R. G. Pritchard ◽  
W. H. Paar ◽  
R. A. D. Pattrick
Keyword(s):  
Atmospheric Pressure ◽  
Site Occupancy ◽  
New Mineral ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Cation Site ◽  
Calculated Density ◽  
X Ray ◽  
Cell Parameters ◽  
Jahn Teller

AbstractTiny green crystals from Kabwe, Zambia, associated with hopeite and tarbuttite (and probably first recorded in 1908 but never adequately characterized because of their scarcity) have been studied by X-ray diffraction, microchemical and electron probe microanalysis, infrared spectroscopy, and synthesis experiments. They are shown to be orthorhombic, stoichiometric CuZnPO4OH, of species rank, forming the end-member of a solid-solution series to libethenite, Cu2PO4OH, and are named zincolibethenite. The libethenite structure is unwilling to accommodate any more Zn substituting for Cu at atmospheric pressure, syntheses using Zn-rich solutions precipitating a mixture of zincolibethenite with hopeite, Zn3(PO4)2.4H2O. Single-crystal X-ray data confirm that the Cu(II) occupies the Jahn-Teller distorted 6-coordinate cation site in the libethenite lattice, and the Zn(II) occupies the 5-coordinate site. The space group of zincolibethenite is Pnnm, the same as that of libethenite, with unit-cell parameters a = 8.326, b = 8.260, c = 5.877 Å , V = 404.5 Å 3, Z = 4, calculated density = 3.972 g/cm3 (libethenite has a = 8.076, b = 8.407, c = 5.898 Å , V = 400.44 Å 3, Z = 4, calculated density = 3.965 g/cm3). Zincolibethenite is biaxial negative, with 2Vα(calc.) of 49°, r<v, and α = 1.660, β = 1.705, and γ = 1.715 The mineral is named for its relationship to libethenite.

Reactions between Co(II), 1,2-bis(diphenylphosphino)ethane, and NaBH3CN in the presence and absence of CO. The crystal structure of bis(cyanotrihydroborato)tetrakis(N,N-dimethylformamide)cobalt(II)

1988 ◽  
Vol 66 (7) ◽  
pp. 1770-1775 ◽  
Author(s):  
David J. Elliot ◽  
Sanna Haukilahti ◽  
David G. Holah ◽  
Alan N. Hughes ◽  
Stanislaw Maciaszek ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Triclinic Space Group ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
R Factor

Reactions between Co(II), Diphos, and NaBH3CN lead to Co(BH3CN)2(Diphos)2, 1, or [Co(BH3CN)(Diphos)2]X, 2 (X = ClO4 or BPh4), and, in certain solvents, 2 reacts to produce [Co(CN)(Diphos)2](ClO4). Compound 1 can be reversibly converted to Co(BH3CN)2(DMF)4, 4, via Co(BH3CN)2(Diphos)(DMF). In addition, 1 reacts with CO to form the Co(I) and Co(III) compounds [Co(Diphos)2](CO)]X and [Co(Diphos)2(CN)2]X (X = BH3CN or BPh4). Single crystal X-ray diffraction studies of 4 show that the compound crystallizes in the triclinic space group [Formula: see text], with unit cell parameters a = 7.572(6), b = 9.695(6), c = 9.395(6) Å, α = 81.06(4), β = 68.46(5), γ = 68.19(5)°, V = 595.5 Å3, Z = 1, and dcalcd = 1.202 g cm−3. The structure converged to a conventional R factor of 0.040 for 2841 observations and showed an octahedral arrangement of four O atoms from DMF molecules and two trans N-bound BH3CN groups around the Co(II) center.

scholarly journals LCP crystallization and X-ray diffraction analysis of VcmN, a MATE transporter fromVibrio cholerae

2016 ◽  
Vol 72 (7) ◽  
pp. 552-557 ◽  
Author(s):  
Tsukasa Kusakizako ◽  
Yoshiki Tanaka ◽  
Christopher J. Hipolito ◽  
Teruo Kuroda ◽  
Ryuichiro Ishitani ◽  
...  
Keyword(s):  
Single Crystal ◽  
Diffraction Data ◽  
Unit Cell ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Mate Transporter

Multidrug and toxic compound extrusion (MATE) transporters, one of the multidrug exporter families, efflux xenobiotics towards the extracellular side of the membrane. Since MATE transporters expressed in bacterial pathogens contribute to multidrug resistance, they are important therapeutic targets. Here, a MATE-transporter homologue fromVibrio cholerae, VcmN, was overexpressed inEscherichia coli, purified and crystallized in lipidic cubic phase (LCP). X-ray diffraction data were collected to 2.5 Å resolution from a single crystal obtained in a sandwich plate. The crystal belonged to space groupP212121, with unit-cell parametersa= 52.3,b= 93.7,c= 100.2 Å. As a result of further LCP crystallization trials, crystals of larger size were obtained using sitting-drop plates. X-ray diffraction data were collected to 2.2 Å resolution from a single crystal obtained in a sitting-drop plate. The crystal belonged to space groupP212121, with unit-cell parametersa= 61.9,b= 91.8,c= 100.9 Å. The present work provides valuable insights into the atomic resolution structure determination of membrane transporters.

Mertieite-II, Pd8Sb2.5As0.5, crystal-structure refinement and formula revision

2018 ◽  
Vol 82 (S1) ◽  
pp. S247-S257 ◽  
Author(s):  
O. V. Karimova ◽  
A. A. Zolotarev ◽  
T. L. Evstigneeva ◽  
B. S. Johanson
Keyword(s):  
Crystal Structure ◽  
Structure Refinement ◽  
Close Packing ◽  
Unit Cell ◽  
Structural Topology ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Finnish Lapland

ABSTRACTThe crystal structure of the mineral mertieite-II from the Kaarreoja River, Inari commune, Finnish Lapland, Finland, was refined to R1 = 0.0222 (I) and 0.0228 (II) on the basis of X-ray diffraction data collected from two single crystals. The mineral is trigonal, space group is $R\bar 3c$. The unit-cell parameters for the two crystals are determined as: a = 7.5172(3), c = 43.037(2) Å, V = 2106.1(2) Å3 (I); a = 7.5135(4), c = 43.003(3) Å, V = 2102.4(3) Å3 (II) with Z = 12. The occupancies of the Sb and As position in the structure were refined according to the Sb:As ratio of each crystal. The position As1 (Wyckoff 6b) is completely filled by As atoms. Any excess of As is distributed together with Sb on structural position M1 (Wyckoff 12c). The crystal chemical formulae are defined as Pd8Sb1.5(Sb0.94As0.06)As0.5 (crystal I) and Pd8Sb1.5(Sb0.88As0.12)As0.5 (crystal II). As → Sb substitution of up to 4.50 wt% of As does not affect the main structural topology of mertieite-II. Mertieite-II, Pd8Sb2.5As0.5 and synthetic Pd8Sb3 are isotypic compounds. The crystal structures of synthetic Pd8Sb3 and natural mertieite-II, Pd8Sb2.5As0.5, can be derived from the hexagonal close packing by filling additional layers between the close-packed 36 layers. The structure consists of Sb and (Sb,As) triangular 36, Pd triangular 36 and Pd pentagonal-triangular 5.33 layers. Stacking of Sb-, (Sb,As)- and Pd-nets along the z axis caused extension of the unit cell. It contains a total of 36 layers: six Sb1-nets, six (M1,As1)-nets, 12 Pd1-nets and 12 (Pd1,Pd3,Pd4)-nets.

Ognitite, NiBiTe, a new mineral species, and Co-rich maucherite from the Ognit ultramafic complex, Eastern Sayans, Russia

2019 ◽  
Vol 83 (5) ◽  
pp. 695-703 ◽  
Author(s):  
Andrei Y. Barkov ◽  
Luca Bindi ◽  
Nobumichi Tamura ◽  
Gennadiy I. Shvedov ◽  
Björn Winkler ◽  
...  
Keyword(s):  
Single Crystal ◽  
Diffraction Data ◽  
Unit Cell ◽  
Synthetic Analogue ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
New Mineral Species ◽  
Ultramafic Complex

AbstractWe describe the new species ognitite, NiBiTe, and a Co-rich variety of maucherite, hitherto unreported; both were discovered in the Ognit ultramafic complex of Neoproterozoic age in Eastern Sayans, Russia. The mean composition of ognitite (n = 7) is: Ni 17.05, Fe 0.07, Cu 0.14, Pd 0.14, Te 32.53, Bi 49.64, total 99.57 wt.%, corresponding to: (Ni1.11Cu0.008Fe0.005Pd0.005)Σ1.13Bi0.90Te0.97 (Σ atoms = 3 apfu). Ognitite is trigonal, space group P3m1 [R1 = 0.0276 for 81 reflections with Fo > 4σ(Fo)]. The unit-cell parameters derived from the single-crystal X-ray diffraction data are: a = 3.928(1) Å, c = 5.385(1) Å and V = 71.95(4) Å3, with Z = 1. The c:a ratio is 1.37. The powder X-ray diffraction data obtained on the same fragment used for the single-crystal study are: a = 3.9332(4) Å, c = 5.3920(6) Å and V = 72.24(1) Å3. Ognitite exhibits the brucite-type structure with edge-sharing NiTe3Bi3 octahedra forming sheets parallel to (0001). It is related to melonite, but is distinct compositionally by the extreme Bi-enrichment (melonite and its synthetic analogue contain <0.4 Bi apfu), and structurally as Bi and Te are ordered at two distinct sites, leading to the loss of the centre of symmetry in ognitite.At more than 9 wt.% Co, or ~2 apfu Co, the core of Co-rich maucherite [(Ni,Co)11As8] in a zoned crystal, which is surrounded by Co-depleted orcelite, far surpasses the norm (≤1 and up to 3.9 wt.% Co). The unit-cell parameters of the Co-rich maucherite are: a = 6.85(2) and c = 21.83(5) Å, which are based on results of synchrotron micro-Laue diffraction.The host rock consists of serpentine, clinochlore (Mg# 95–97) and skeletal chromite. We favour the metastable crystallisation of fluid-saturated globules of a sulfide–arsenide melt to explain the anomalous compositions of ore minerals at Ognit. These anomalies seem consistent with rapid cooling in a fluid-enriched system, possibly related to late-stage degassing of the magma, as reflected in a prominent metasomatic aureole at the contact with the enclosing gneissic rocks.

Darstellung und Struktur von NaAu3Si und NaAu3Ge / Preparation and Crystal Structure of NaAu3Si and NaAu3Ge

1980 ◽  
Vol 35 (11) ◽  
pp. 1482-1483 ◽  
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Diffraction Data ◽  
Ternary Systems ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
New Compounds

Abstract In the course of our investigations of the ternary systems Na-Au-Si(Ge) we obtained the new compounds NaAu3Si and NaAu3Ge. Their crystal structure has been determined from single crystal X-ray diffraction data. They crystallize in the cubic space group Pa 3 with unit cell parameters a = 891,6 pm and a = 902,1 pm, resp., and Z = 8.

scholarly journals Ardennite-bearing mineral association related to sulfide-free ores with chalcophile metals at Nežilovo, Pelagonian Massif, North Macedonia

2021 ◽  
Vol 33 (4) ◽  
pp. 433-445
Author(s):  
Marko Bermanec ◽  
Nikita V. Chukanov ◽  
Ivan Boev ◽  
Božidar Darko Šturman ◽  
Vladimir Zebec ◽  
...  
Keyword(s):  
Single Crystal ◽  
Microprobe Analysis ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Mineral Association ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Formation Conditions ◽  
Pelagonian Massif

Abstract. Among numerous minerals determined at Nežilovo, Pelagonian Massif, North Macedonia, ardennite-(As) has been discovered in two different associations and studied by means of optical microscopy, electron microprobe analysis (EMPA), and single-crystal and powder X-ray diffraction methods. The refractive indices of ardennite-(As) from Nežilovo are α=1.537(2), β=1.579(1) and γ=1.741(1), where γ corresponds to the c direction. The optical axial angle is 2Vx=49(1)∘. EMPA of the investigated samples yields the following empirical formulae: [Mn3.272+Ca0.73]Σ4.00[Al4.18Mg1.24Fe0.29Mn0.193+Zn0.10]Σ6.00(Si4.73Al0.27)Σ5.00(As0.96Si0.03V0.01)Σ1.00O22 [OH5.36(H2O)0.64]Σ6.00 for ardennite-(As) and (K0.95Na0.04Ba0.02)Σ1.01(Al1.44Fe0.303+Mg0.20Mn0.03Ti0.02 Zn0.01)Σ2.00(Si3.21Al0.79O10) (OH1.97O0.03)Σ2.00 for the associated red mica. The unit cell parameters of ardennite-(As) determined by X-ray powder diffraction are a=8.757(2) Å, b=5.836(2) Å, c=18.578(2) Å and V=941.97 Å3. The unit cell parameters of ardennite-(As) were also determined by single-crystal X-ray diffraction and are a=8.760(1) Å, b=5.838(1) Å, c=18.582(2) Å and V=950.30 Å3. Regularities of isomorphism in ardennite-related minerals are discussed. The presence of ardennite-(As) in association with 2M1 and 3T phengite polytypes provides evidence for three separate stages of formation. Conditions at which ardennite-(As) crystallized have been estimated based on compositional features of associated micas.

Darstellung und Struktur des KAu4Sn2 / Preparation and Crystal Structure of KAu4Sn2

1978 ◽  
Vol 33 (10) ◽  
pp. 1077-1079 ◽  
Author(s):  
Heinz-Dieter Sinnen ◽  
Hans-Uwe Schuster
Keyword(s):  
Crystal Structure ◽  
Ternary System ◽  
Single Crystal ◽  
Diffraction Data ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters

Abstract In the course of our investigation of the ternary system K-Au-Sn we obtained the new compound KAu4Sn2. Its crystal structure has been determinated from single crystal X-ray diffraction data. It crystallizes in the tetragonal space group 1̅4̅c2 with unit-cell parameters a = 884.7 and c = 817.8 pm and Z = 4. The structure is comparable to that of the Tl2Se.

scholarly journals Crystal Structure Refinements of Four Monazite Samples from Different Localities

Minerals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1028 ◽  
Author(s):  
M. Mashrur Zaman ◽  
Sytle M. Antao
Keyword(s):  
Crystal Structure ◽  
Electron Probe ◽  
Unit Cell Volume ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Large Unit Cell ◽  
A Site

This study investigates the crystal chemistry of monazite (APO4, where A = Lanthanides = Ln, as well as Y, Th, U, Ca, and Pb) based on four samples from different localities using single-crystal X-ray diffraction and electron-probe microanalysis. The crystal structure of all four samples are well refined, as indicated by their refinement statistics. Relatively large unit-cell parameters (a = 6.7640(5), b = 6.9850(4), c = 6.4500(3) Å, β = 103.584(2)°, and V = 296.22(3) Å3) are obtained for a detrital monazite-Ce from Cox’s Bazar, Bangladesh. Sm-rich monazite from Gunnison County, Colorado, USA, has smaller unit-cell parameters (a = 6.7010(4), b = 6.9080(4), c = 6.4300(4) Å, β = 103.817(3)°, and V = 289.04(3) Å3). The a, b, and c unit-cell parameters vary linearly with the unit-cell volume, V. The change in the a parameter is large (0.2 Å) and is related to the type of cations occupying the A site. The average <A-O> distances vary linearly with V, whereas the average <P-O> distances are nearly constant because the PO4 group is a rigid tetrahedron.

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