scholarly journals Packing polymorphism in the structure oftrans-aqua[N,N′-bis(salicylidene)ethane-1,2-diamine-κ4O,N,N′,O′]chloridomanganese(III) monohydrate

2018 ◽  
Vol 74 (12) ◽  
pp. 1778-1782
Author(s):  
Juan Alberto Reyes Perea ◽  
Sylvain Bernès ◽  
Ma Guadalupe Quintero Téllez
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Unit Cell Parameter ◽  
Molecular Conformation ◽  
Cell Parameter ◽  
Title Complex ◽  
Unit Cell ◽  
Alternative Synthesis ◽  
Space Group ◽  
Structural Database

The crystal structure of the title complex (systematic name:trans-aquachlorido{2,2′[ethane-1,2-diylbis(nitrilomethylidyne)]diphenolato-κ4O,N,N′,O′}manganese(III) monohydrate), [Mn(C16H14N2O2)Cl(H2O)]·H2O has been reported previously in the space groupP21/n[Panjaet al.(2003).Polyhedron,22, 1191–1198]. We obtained the same hydrated complex through an alternative synthesis, and crystallized a new polymorph, in the space groupP21. The molecular conformation of the complex is virtually unmodified, but the absence of the glide plane in the new polymorph halves the unit-cell parameterc, affording a non-centrosymmetric crystal structure withZ= 2, while the previously reported crystal is centrosymmetric withZ= 4. Both phases represent a case of packing polymorphism, similar to other dimorphic crystal structures retrieved from the Cambridge Structural Database.

About the crystal structure of La1−xSrxCoO3−δ (0≤x≤0.6)

1996 ◽  
Vol 11 (1) ◽  
pp. 31-34 ◽  
Author(s):  
Nicole M. L. N. P. Closset ◽  
René H. E. van Doorn ◽  
Henk Kruidhof ◽  
Jaap Boeijsma
Keyword(s):  
Crystal Structure ◽  
Unit Cell Parameter ◽  
Cell Parameter ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters

The crystal structure of La1−xSrxCoO3−δ (0≤x≤0.6) has been studied, using powder X-Ray diffraction. The crystal structure shows a transition from rhombohedral distorted perovskite for LaCoO3−δ into cubic perovskite for La0.4Sr0.6CoO3−δ. The cubic unit cell parameter is ac=3.8342(1) Å for La0.4Sr0.6CoO3−δ, the space group probably being Pm3m. Using a hexagonal setting, the cell parameters for La0.5Sr0.5CoO3−δ, are a=5.4300(3) Å, c=13.2516(10) Å; a=5.4375(1) Å, c=13.2313(4) Å for La0.6Sr0.4CoO3−δ; a=5.4437(1) Å, c=13.2085(5) Å for La0.7Sr0.3CoO3−δ; a=5.4497(2) Å, c=13.1781(6) Å for La0.8Sr0.2CoO3−δ and a=5.4445(2) Å, c=13.0936(6) Å for LaCoO3−δ with the space group probably being R3c.

Crystal-chemistry of sulfates from the Apuan Alps (Tuscany, Italy). VI. Tl-bearing alum-(K) and voltaite from the Fornovolasco mining complex

2020 ◽  
Vol 105 (7) ◽  
pp. 1088-1098 ◽  
Author(s):  
Cristian Biagioni ◽  
Daniela Mauro ◽  
Marco Pasero ◽  
Elena Bonaccorsi ◽  
Giovanni Orazio Lepore ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Unit Cell Parameter ◽  
Cell Parameter ◽  
Unit Cell ◽  
Partial Substitution ◽  
Chemical Formula ◽  
Space Group ◽  
X Ray ◽  
Mining Complex ◽  
Apuan Alps

Abstract Thallium-bearing samples of alum-(K) and voltaite from the Fornovolasco mining complex (Apuan Alps, Tuscany, Italy) have been characterized through X-ray diffraction, chemical analyses, micro-Raman, infrared (FTIR), Mössbauer, and X-ray absorption spectroscopy (XAS). Alum-(K) occurs as anhedral colorless grains or rarely as octahedral crystals, up to 5 mm. Electron-microprobe analysis points to the chemical formula (K0.74Tl0.10)Σ0.84(Al0.84Fe0.14)Σ0.98S2.03O8·12H2O. The occurrence of minor NH4+ was detected through FTIR spectroscopy. Its unit-cell parameter is a = 12.2030(2) Å, V = 1817.19(9) Å3, space group Pa3. Its crystal structure has been refined down to R1 = 0.0351 for 648 reflections with Fo > 4σ(Fo) and 61 refined parameters. The crystal structure refinement agrees with the partial substitution of K by 12 mol% Tl. This substitution is confirmed by XAS data, showing the presence of Tl+ having a first coordination shell mainly formed by 6 O atoms at 2.84(2) Å. Voltaite occurs as dark green cubic crystals, up to 1 mm in size. Voltaite is chemically zoned, with distinct domains having chemical formula (K1.94Tl0.28)Σ2.22(Fe3.572+Mg0.94Mn0.55)Σ5.06Fe3.063+Al0.98S11.92O48·18H2O and (K2.04Tl0.32)Σ2.36(Fe3.832+Mg0.91Mn0.29)Σ5.03Fe3.053+Al0.97S11.92O48·18H2O, respectively. Infrared spectroscopy confirmed the occurrence of minor NH4+ also in voltaite. Its unit-cell parameter is a = 27.2635 Å, V = 20265(4) Å3, space group Fd3c. The crystal structure was refined down to R1 = 0.0434 for 817 reflections with Fo > 4σ(Fo) and 87 refined parameters. The partial replacement of K by Tl is confirmed by the structural refinement. XAS spectroscopy showed that Tl+ is bonded to six O atoms, at 2.89(2) Å. The multi-technique characterization of thallium-bearing alum-(K) and voltaite improves our understanding of the role of K-bearing sulfates in immobilizing Tl in acid mine drainage systems, temporarily avoiding its dispersion in the environment.

scholarly journals Crystal structure of bis{μ-(E)-2-[(2-oxidophenylimino)methyl]quinolin-8-olato-κ4O,N,N′,O′}bis[dibutyltin(IV)]

2017 ◽  
Vol 73 (1) ◽  
pp. 4-7
Author(s):  
Camacho-Camacho Carlos ◽  
Ortiz-Pastrana Naytzé ◽  
Garza-Ortiz Ariadna ◽  
Rojas-Oviedo Irma
Keyword(s):  
Crystal Structure ◽  
Schiff Base ◽  
Metal Atom ◽  
Title Complex ◽  
Unit Cell ◽  
Type Structure ◽  
Triclinic Space Group ◽  
Space Group ◽  
Centrosymmetric Dimers ◽  
Oxygen Atoms

Condensation of 8-hydroxyquinoline-2-carbaldehyde with 2-aminophenol gave the (E)-2-[(2-hydroxyphenylimino)methyl]quinolin-8-ol derivative that reacted with di-n-butyltin oxide with release of H2O to yield the chelate title complex, [Sn2(C4H9)4(C16H10N2O2)2]. The compound crystallizes in the triclinic space groupP-1, with two independent centrosymmetric dimers in the unit cell. Each features a typical pincer-type structure where the dianionic ligand is tetradentate, coordinating to the central tin atom through both phenolate oxygen atoms, as well as through the quinoline and imine N atoms. Each metal atom adopts a distorted pentagonal–bipyramidal SnC2N2O3coordination arising from theN,N′,O,O′-tetradentate deprotonated Schiff base, one bridging phenolate O atom of the neighbouring ligand and two butyl groups in the axial sites.

Dynamics of the crystal structure of tin-based type-I clathrates with different degrees of disorder in their cationic frameworks

2017 ◽  
Vol 19 (40) ◽  
pp. 27725-27730 ◽  
Author(s):  
V. V. Novikov ◽  
K. S. Pilipenko ◽  
A. V. Matovnikov ◽  
N. V. Mitroshenkov ◽  
B. I. Kornev ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Heat Capacity ◽  
Unit Cell Parameter ◽  
Lattice Dynamics ◽  
Cell Parameter ◽  
Unit Cell ◽  
Type I

The temperature dependencies of heat capacity and cubic unit cell parameter for type-I clathrates were obtained to determine the influence of the concentration of vacancies and substituting atoms on the lattice dynamics.

Molecular and Crystal Structure of Sildenafil Base

2012 ◽  
Vol 67 (5) ◽  
pp. 491-494 ◽  
Author(s):  
Dmitrijs Stepanovs ◽  
Anatoly Mishnev
Keyword(s):  
Crystal Structure ◽  
Erectile Dysfunction ◽  
Crystal Structures ◽  
Unit Cell ◽  
Sildenafil Citrate ◽  
Unit Cell Parameters ◽  
Monoclinic System ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters

Sildenafil citrate monohydrate, well known as Viagra®, is a drug for the treatment of erectile dysfunction. Here we present the X-ray crystal structure of the sildenafil base, C22H30N6O4S. The compound crystallizes in the monoclinic system, space group P21/c with the unit cell parameters a = 17:273(1), b=17:0710(8), c=8:3171(4) Å , b =99:326(2), Z = 4, V = 2420:0(3) Å3. A comparison with the known crystal structures of sildenafil citrate monohydrate and sildenafil saccharinate is also presented.

Halogen NQR and Crystal Structure of Ammonium Halides (R-NH3)+X- and (X–) (+H3NR´­NH3+) (X–). R = (HOCH2)3C, R´ = CH2C(CH3)2CH2; X = I,Br

1994 ◽  
Vol 49 (1-2) ◽  
pp. 174-184
Author(s):  
Shi-qi Dou ◽  
Hartmut Fuess ◽  
Helmut Paulus ◽  
Alarich Weiss
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Unit Cell ◽  
Space Group ◽  
Temperature Range ◽  
Ammonium Halides

AbstractThe 127I-NQR of(HOCH2)3CNH3+ I- was determined in the range 77 ≤ T/K ≤ 310. At T = 310 K the NQR signal fades out (Tm = 463 K). The 127I spectrum ( T =77 K.): v1 =29.195 MHz, v2 = 14.597 MHz, η(121l)=0, e QΦzz h-1 (127I) = 97.315 MHz, is in agreement with the crystal structure. The 127I NQR spectrum of 1,3-diammonium-2,2-dimethylpropane diiodide, (H3NCH2C(CH3)2CH2NH3)2+ ·2I- , is a quartet within the whole temperature range investigated, and the lines correspond to two crystallographically independent iodines: Space group P21/c, Z = 4, a = 731.2(3) pm, b = 689.0(3) pm, c = 2255.1(8) pm, β = 104.90(1)°. At 7 = 7 7 K the 127I NQR quartet is (MHz): v1 = 34.145, v2 = 32.805, v3 = 22.113, v4 = 16.787; at 295 K (same order, MHz): 30.559, 29.729, 19.810, 15.651. There are two combinations of the NQR frequencies. Considering the coordination of I-, the hydrogen bonds N -H ··· I, eQΦzzQ h-1 and η, we choose for I(1) v1 and v3, for I(2) v2 and v4. At 77 K eQΦzzQ h-1 (I(1))= 118.86 MHz,η (127I(1)) = 0.498, eQΦzzQ h-1 (I(2)) = 109.75 MHz, η(127I(2)) = 0.135 follow for the two iodine atoms. Both, eQΦzzQ h-1 (I(1)) and e eΦzzQ h-1(I(2)) decrease smoothly with increasing T: η I(2)) increases with increasing T whereas η(127I(1)) is almost constant within 77 ≤ T /K ≤ 4 0 6 . The 79,81Br NQR spectrum of l,3-diamino-2,2-dimethylpropane dihydrobromide is also a quartet, showing two crystallographic inequivalent Br atoms in the unit cell. The frequencies are (T =273 K, MHz): v1 (79Br)= 14.303, v2 (79Br)= 12.884, (81Br)= 11.951, v2(81Br) = 10.781; space group C2/c, Z = 8 , a = 2136.4(6) pm, b = 854.6(3) pm, c = 1125.8(3) pm, β = 93.23(1)°. Crystal structures and NQR results are discussed.

scholarly journals Crystal Structure of an Anisotropic Pyrope Garnet That Contains Two Cubic Phases

Minerals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1320
Author(s):  
Sytle M. Antao
Keyword(s):  
Crystal Structure ◽  
Unit Cell Parameter ◽  
Cell Parameter ◽  
Rietveld Method ◽  
Unit Cell ◽  
Cubic Phase ◽  
Average Composition ◽  
Weight Percentage ◽  
Cubic Phases ◽  
De Beers

The crystal structure of two different samples of pyrope garnet, ideally Mg3Al2Si3O12, from South Africa was refined using the Rietveld method, space group Ia3¯d, and monochromatic synchrotron high-resolution powder X-ray diffraction (HRPXRD) data. Sample 1 from Wesselton Mine is a single cubic phase and is optically isotropic. Electron-probe microanalysis (EPMA) provided an average composition {Mg2.30Fe2+0.26Ca0.42Mn2+0.02}∑3[Al1.53Fe3+0.06Cr3+0.40Ti4+0.01Fe2+0.01]∑2Si3O12, which contains a significant amount of Cr cations. The unit-cell parameter (Å) and bond distances (Å) are a = 11.56197(1) Å, average <Mg-O> = 2.2985, Al-O = 1.9101(4), and Si-O = 1.6343(3) Å. Sample 2 from De Beers Diamond Mine has an average composition {Mg2.33Fe2+0.33Ca0.33Mn2+0.01}∑3[Al1.73Fe3+0.12Cr3+0.06Ti4+0.05Fe2+0.05]∑2Si3O12 and is a fine-scale intergrowth of two cubic phases. The weight percentage, unit-cell parameter (Å), and bond distances (Å) for phase 2a are 62.2(1)%, a = 11.56185(1) Å, average <Mg-O> = 2.3006, Al-O = 1.9080(4), Si-O = 1.6334(4) Å. The corresponding values for phase 2b are 37.8(1)%, a = 11.53896(1) Å, average <Mg-O> = 2.2954, Al-O = 1.9020(6), Si-O = 1.6334(6) Å. The two cubic phases in sample 2 cause the crystal to be optically anisotropic because of strain induce birefringence. The unit-cell parameter and bond distances for sample 1 are similar to those in phase 2a.

scholarly journals Crystal structures of 2-[3,5-bis(bromomethyl)-2,4,6-triethylbenzyl]isoindoline-1,3-dione and 2-{5-(bromomethyl)-3-[(1,3-dioxoisoindolin-2-yl)methyl]-2,4,6-triethylbenzyl}isoindoline-1,3-dione

2021 ◽  
Vol 77 (9) ◽  
Author(s):  
Manuel Stapf ◽  
Betty Leibiger ◽  
Anke Schwarzer ◽  
Monika Mazik
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Molecular Conformation ◽  
Halogen Bond ◽  
Asymmetric Unit ◽  
Space Group ◽  
Π Interactions ◽  
Hydrogen Bonding Interactions

The title compounds, C23H25Br2NO2 (1) and C31H29BrN2O4 (2), crystallize in the space group P21/n with two (1-A and 1-B) and one molecules, respectively, in the asymmetric unit of the cell. The molecular conformation of these compounds is stabilized by intramolecular C—H...O hydrogen bonds and C—H...N or C—H...π interactions. The crystal structure of 1 features a relatively strong Br...O=C halogen bond, which is not observed in the case of 2. Both crystal structures are characterized by the presence of C—H...Br hydrogen bonds and numerous intermolecular C—H...O hydrogen-bonding interactions.

scholarly journals Crystal chemistry of natural layered double hydroxides. 5. Single-crystal structure refinement of hydrotalcite, [Mg6Al2(OH)16](CO3)(H2O)4

2018 ◽  
Vol 83 (02) ◽  
pp. 269-280 ◽  
Author(s):  
Elena S. Zhitova ◽  
Sergey V. Krivovichev ◽  
Igor Pekov ◽  
H. Christopher Greenwell
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Crystal Structures ◽  
Structure Refinement ◽  
Unit Cell ◽  
Single Crystal Structure ◽  
Unit Cell Parameters ◽  
Diagnostic Features ◽  
Space Group ◽  
Cell Parameters

AbstractHydrotalcite, ideally [Mg6Al2(OH)16](CO3)(H2O)4, was studied in samples from Dypingdal, Snarum, Norway (3R and 2H), Zelentsovskaya pit (2H) and Praskovie–Evgenievskaya pit (2H) (both Southern Urals, Russia), Talnakh, Siberia, Russia (3R), Khibiny, Kola, Russia (3R), and St. Lawrence, New York, USA (3R and 2H). Two polytypes, 3R and 2H (both ‘classical’), were confirmed on the basis of single-crystal and powder X-ray diffraction data. Their chemical composition was studied by electron-microprobe analysis, infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. The crystal structure of hydrotalcite-3R was solved by direct methods in the space group R$ {\bar 3} $m on three crystals (two data collections at 290 K and one at 120 K). The unit-cell parameters are as follows (290/290/120 K): a = 3.0728(9)/3.0626(3)/3.0617(4), c = 23.326(9)/23.313(3)/23.203(3) Å and V = 190.7(1)/189.37(4)/188.36(4) Å3. The crystal structures were refined on the basis of 304/150/101 reflections to R1 = 0.075/0.041/0.038. Hydrotalcite-2H crystallises in the P63/mmc space group; unit-cell parameters for two crystals are (data collection at 290 K and 93 K): a = 3.046(1)/3.0521(9), c = 15.447(6)/15.439(4) Å, V = 124.39(8)/124.55(8) Å3. The crystal structures were refined on the basis of 160/142 reflections to R1 = 0.077/0.059. This paper reports the first single-crystal structure data on hydrotalcite. Hydrotalcite distribution in Nature, diagnostic features, polytypism, interlayer topology and localisation of M2+–M3+ cations within metal hydroxide layers are discussed.

An Unusual cis-Dichloro[17-(cyclobutylmethyl)-3-methoxymorphinan-14-ol-N,O]palladium(II) Complex

2006 ◽  
Vol 71 (3) ◽  
pp. 434-442
Author(s):  
Alexandr Jegorov ◽  
Hana Petříčková ◽  
Bohumil Kratochvíl ◽  
Ivana Císařová
Keyword(s):  
Crystal Structure ◽  
Coordination Sphere ◽  
Tertiary Amine ◽  
Tertiary Alcohol ◽  
Title Complex ◽  
Unit Cell ◽  
Chlorine Atoms ◽  
Synthesis And Crystal Structure ◽  
Space Group ◽  
Independent Molecules

Synthesis and crystal structure of cis-dichloro[17-(cyclobutylmethyl)-3-methoxymorphinan-14-ol-N,O]palladium(II) methanol solvate is reported. The title complex crystallises in the triclinic P1 space group and is remarkable both by the number of independent molecules in the unit cell and the coordination sphere of palladium(II) formed by tertiary alcohol, tertiary amine and two chlorine atoms.

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