Defect Crystal Structure of Low Temperature Modifications of Li2MO3 (M=Ti, Sn) and Related Hydroxides

2010 ◽  
Vol 63 ◽  
pp. 352-357 ◽  
Author(s):  
Nadezda V. Tarakina ◽  
Tatiana A. Denisova ◽  
Yana V. Baklanova ◽  
Lidia G. Maksimova ◽  
Vladimir G. Zubkov ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Structure Type ◽  
High Concentration ◽  
X Ray ◽  
Space Groups ◽  
Defect Crystal ◽  
Double Hydroxide ◽  
Metal Layers ◽  
Neutral Metal

Crystal structures of Li2MO3 (M=Sn, Ti) and TiO(OH)2 have been studied in detail and refined using X-ray powder diffraction data. All compounds posses a high concentration of defects in the structure. The crystal structures of the Li2MO3 salts obtained at 700°C reveal stacking faults of LiM2 metal layers, which leads to the appearance of short-range order in three possible space groups: C2/c, C2/m, P3112. The possibility to stabilize this imperfect state increases the mobility of the Li+ ions in the Li2TiO3 structure and allows the complete exchange of lithium by hydrogen in acid water solutions with formation of TiO(OH)2. The crystal structure of TiO(OH)2 belongs to the layered double hydroxide structure type with the 3R1 sequence of oxygen layers and can be described as a stacking of charge-neutral metal oxyhydroxide slabs [(OH)2OTi2O(OH)2].

Über die Kristallstrukturen der Tellurate Pb3Fe2Te2O12 und Pb2CoTeO6 / On the Crystal Structures of the Tellurates Pb3Fe2Te2O12 and Pb2CoTeO6

1997 ◽  
Vol 52 (1) ◽  
pp. 35-39 ◽  
Author(s):  
B. Wedel ◽  
Hk. Müller-Buschbaum
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Crystal Structures ◽  
Negative Charge ◽  
X Ray ◽  
Space Groups ◽  
Lattice Constants ◽  
Coulomb Term ◽  
Lone Pairs ◽  
Symmetry Space

Pb3Fe2Te2O12 (I) and Pb2CoTeO6 (II) have been prepared by crystallization from melts. Single crystal X-ray investigations led to monoclinic (I) and tetragonal (II) symmetry, space groups C4s-Cc and D174h-14/mmm. Lattice constants I: a = 9.866(3), b = 15.332(4), c = 7.172(2) Å, β = 111.34(3)°, Z = 4. II: a = 5.661(5), c = 8.004(7) Å, Z = 2. (I) represents a new crystal structure, characterized by a network of octahedra occupied by Fe3+ and Te6+ in a disordered manner. The centres of negative charge of the lone pairs of Pb2+ in I are estimated by Coulomb term calculations. II belongs to the elpasolithe type

Determination of the structure of the violet pigment C22H12Cl2N6O4 from a non-indexed X-ray powder diagram

2005 ◽  
Vol 61 (1) ◽  
pp. 37-45 ◽  
Author(s):  
Martin U. Schmidt ◽  
Martin Ermrich ◽  
Robert E. Dinnebier
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Lattice Energy ◽  
Frankfurt Am Main ◽  
Rietveld Refinements ◽  
X Ray ◽  
Space Groups ◽  
Violet Pigment

The violet pigment methylbenzimidazolonodioxazine, C22H12Cl2N6O4 (systematic name: 6,14-dichloro-3,11-dimethyl-1,3,9,11-tetrahydro-5,13-dioxa-7,15-diazadiimidazo-[4,5-b:4′,5′-m]pentacene-2,10-dione), shows an X-ray powder diagram consisting of only ca 12 broad peaks. Indexing was not possible. The structure was solved by global lattice energy minimizations. The program CRYSCA [Schmidt & Kalkhof (1999), CRYSCA. Clariant GmbH, Pigments Research, Frankfurt am Main, Germany] was used to predict the possible crystal structures in different space groups. By comparing simulated and experimental powder diagrams, the correct structure was identified among the predicted structures. Owing to the low quality of the experimental powder diagram the Rietveld refinements gave no distinctive results and it was difficult to prove the correctness of the crystal structure. Finally, the structure was confirmed to be correct by refining the crystal structure of an isostructural mixed crystal having a better X-ray powder diagram. The compound crystallizes in P\bar 1, Z = 1. The crystal structure consists of a very dense packing of molecules, which are connected by hydrogen bridges of the type N—H...O=C. This packing explains the observed insolubility. The work shows that crystal structures of molecular compounds may be solved by lattice energy minimization from diffraction data of limited quality, even when indexing is not possible.

Synthese und Kristallstruktur von Dibariumzink-bis(cyclotriborat) Ba2Zn(B3O6)2/Synthesis and Crystal Structure of Di-barium Zinc Bis-cyclotriborate Ba2Zn(B3O6)2

1996 ◽  
Vol 51 (3) ◽  
pp. 309-312 ◽  
Author(s):  
Silke Busche ◽  
Karsten Bluhm
Keyword(s):  
Crystal Structure ◽  
High Temperature ◽  
Single Crystals ◽  
Crystal Structures ◽  
Structure Type ◽  
Lattice Parameters ◽  
Synthesis And Crystal Structure ◽  
Space Group ◽  
X Ray ◽  
Unknown Structure

Abstract Single crystals of the new compound Ba2Zn(B3O6)2 were obtained by using a B2O3 flux technique. They crystallize in an as yet unknown structure type. X-ray investigations led to space group Ci1-P1̄ (Nr.2) with lattice parameters a = 715.5(2), b = 720.5(2), c = 1178.9(4), a = 78.96(2)°, β = 85.45(2)°, γ = 60.12(1)°, Z = 2. The structure is characterized by iso­lated (B3O6)3--rings and contains two ninefold coordinated Ba-sites. Zn2+ is tetrahedrally coordinated by oxygen. The relation to the crystal structures of high-temperature BaB2O4 and Ba2Ca(B3O6)2 is discussed.

Die Kristallstrukturen von PPh4[SnCl3] und PPh4[SnBr3]/ The Crystal Structures of PPh4[SnCl3] and PPh4[SnBr3]

1982 ◽  
Vol 37 (9) ◽  
pp. 1122-1126 ◽  
Author(s):  
Ulrich Müller ◽  
Norbert Mronga ◽  
Christina Schumacher ◽  
Kurt Dehnicke
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Vibrational Spectra ◽  
Diffraction Data ◽  
Structure Type ◽  
X Ray Diffraction ◽  
Triclinic Space Group ◽  
X Ray ◽  
Structure Determinations ◽  
The Ideal

AbstractPPh4[SnCl3] and PPh4[SnBr3] were prepared by reaction of PPh4X with SnX2 in CH2X2 solutions (X - Cl, Br). The vibrational spectra of the [SnX3]⊖ ions show three SnX3 stretching frequencies, which is caused by deviations from the ideal C3v symmetry. In the crystal structure determinations these deviations show up by slightly different Sn-X bond lengths which are explained by differing hydrogen bridges to phenyl-H atoms. The isotypic crystal structures of both compounds were determined and refined from X-ray diffraction data (R values: 0.042 and 0.034). Although triclinic (space group P1̄), the structures are closely related to the tetragonal AsPh4[RuNCl4] structure type. Very pure SnBr2 is prepared by the reaction of PPh4[SnBr3] with AlBr3 in CH2Br2 solution.

Experimental and predicted crystal structures of Pigment Red 168 and other dihalogenated anthanthrones

2010 ◽  
Vol 66 (5) ◽  
pp. 515-526 ◽  
Author(s):  
Martin U. Schmidt ◽  
Erich F. Paulus ◽  
Nadine Rademacher ◽  
Graeme M. Day
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Lattice Energy ◽  
Molecular Structures ◽  
Actual Structure ◽  
Compound A ◽  
X Ray ◽  
Space Groups ◽  
Cell Parameters ◽  
Experimental Diagram

The crystal structures of 4,10-dibromo-anthanthrone (Pigment Red 168; 4,10-dibromo-dibenzo[def,mno]chrysene-6,12-dione), 4,10-dichloro- and 4,10-diiodo-anthanthrone have been determined by single-crystal X-ray analyses. The dibromo and diiodo derivatives crystallize in P21/c, Z = 2, the dichloro derivative in P\bar 1, Z = 1. The molecular structures are almost identical and the unit-cell parameters show some similarities for all three compounds, but the crystal structures are neither isotypic to another nor to the unsubstituted anthanthrone, which crystallizes in P21/c, Z = 8. In order to explain why the four anthanthrone derivatives have four different crystal structures, lattice-energy minimizations were performed using anisotropic atom–atom model potentials as well as using the semi-classical density sums (SCDS-Pixel) approach. The calculations showed the crystal structures of the dichloro and the diiodo derivatives to be the most stable ones for the corresponding compound; whereas for dibromo-anthanthrone the calculations suggest that the dichloro and diiodo structure types should be more stable than the experimentally observed structure. An experimental search for new polymorphs of dibromo-anthanthrone was carried out, but the experiments were hampered by the remarkable insolubility of the compound. A metastable nanocrystalline second polymorph of the dibromo derivative does exist, but it is not isostructural to the dichloro or diiodo compound. In order to determine the crystal structure of this phase, crystal structure predictions were performed in various space groups, using anisotropic atom–atom potentials. For all low-energy structures, X-ray powder patterns were calculated and compared with the experimental diagram, which consisted of a few broad lines only. It turned out that the crystallinity of this phase was not sufficient to determine which of the calculated structures corresponds to the actual structure of this nanocrystalline polymorph.

Crystal structure variations in the series SrLnCuS3 (Ln = La, Pr, Sm, Gd, Er and Lu)

2019 ◽  
Vol 75 (5) ◽  
pp. 584-588 ◽  
Author(s):  
Anna V. Ruseikina ◽  
Leonid A. Solovyov ◽  
Maksim V. Grigoriev ◽  
Oleg V. Andreev
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Ionic Radius ◽  
Structure Type ◽  
Structure Parameters ◽  
X Ray Diffraction ◽  
X Ray

The crystal structures of the complex sulfides SrLnCuS3 (Ln = Sm, Gd, Er and Lu) have been determined and refined using powder X-ray diffraction. The crystals are found to be orthorhombic, with the structure type changing consecutively in the order BaLaCuS3 → Eu2CuS3 → KZrCuS3 as the Ln3+ ionic radius decreases in the order La/Pr → Sm/Gd → Er/Lu. Variations of the structure parameters along the series of compounds studied are analyzed, and an effect caused by crystallochemical contraction on the stabilization of the respective structure types is demonstrated.

scholarly journals Crystal Chemical Relations in the Shchurovskyite Family: Synthesis and Crystal Structures of K2Cu[Cu3O]2(PO4)4 and K2.35Cu0.825[Cu3O]2(PO4)4

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 807
Author(s):  
Ilya V. Kornyakov ◽  
Sergey V. Krivovichev
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Structural Complexity ◽  
Crystal Chemical ◽  
X Ray Diffraction ◽  
Complexity Measures ◽  
X Ray ◽  
The Family ◽  
Similarities And Differences ◽  
Related Compounds

Single crystals of two novel shchurovskyite-related compounds, K2Cu[Cu3O]2(PO4)4 (1) and K2.35Cu0.825[Cu3O]2(PO4)4 (2), were synthesized by crystallization from gaseous phase and structurally characterized using single-crystal X-ray diffraction analysis. The crystal structures of both compounds are based upon similar Cu-based layers, formed by rods of the [O2Cu6] dimers of oxocentered (OCu4) tetrahedra. The topologies of the layers show both similarities and differences from the shchurovskyite-type layers. The layers are connected in different fashions via additional Cu atoms located in the interlayer, in contrast to shchurovskyite, where the layers are linked by Ca2+ cations. The structures of the shchurovskyite family are characterized using information-based structural complexity measures, which demonstrate that the crystal structure of 1 is the simplest one, whereas that of 2 is the most complex in the family.

X-ray and neutron diffraction study of the defect crystal structure of the as-grown nonstoichiometric phase Y0.715Ca0.285F2.715

2013 ◽  
Vol 58 (4) ◽  
pp. 575-585 ◽  
Author(s):  
N. B. Bolotina ◽  
A. I. Kalyukanov ◽  
T. S. Chernaya ◽  
I. A. Verin ◽  
I. I. Buchinskaya ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Neutron Diffraction ◽  
Diffraction Study ◽  
Neutron Diffraction Study ◽  
Nonstoichiometric Phase ◽  
X Ray ◽  
Defect Crystal

Crystal chemistry of transition metal diarsenates M 2As2O7 (M = Mn, Co, Ni, Zn): variants of the thortveitite structure

2010 ◽  
Vol 66 (6) ◽  
pp. 603-614 ◽  
Author(s):  
Matthias Weil ◽  
Berthold Stöger
Keyword(s):  
Crystal Structure ◽  
Low Temperature ◽  
Transition Metal ◽  
Basic Structure ◽  
Structure Type ◽  
Ambient Conditions ◽  
Modulated Structure ◽  
Triclinic Crystal System ◽  
Space Groups ◽  
Unit Cells

The structures of the 3d divalent transition-metal diarsenates M 2As2O7 (M = Mn, Co, Ni, Zn) can be considered as variants of the monoclinic (C2/m) thortveitite [Sc2Si2O7] structure type with a ≃ 6.7, b ≃ 8.5, c ≃ 4.7 Å, α ≃ 90, β ≃ 102, γ ≃ 90° and Z = 2. Co2As2O7 and Ni2As2O7 are dimorphic. Their high-temperature (β) polymorphs adopt the thortveitite aristotype structure in C2/m, whereas their low-temperature (α) polymorphs are hettotypes and crystallize with larger unit cells in the triclinic crystal system in space groups P\bar 1 and P1, respectively. Mn2As2O7 undergoes no phase transition and likewise adopts the thortveitite structure type in C2/m. Zn2As2O7 has an incommensurately modulated crystal structure [C2/m(α,0,γ)0s] with q = [0.3190 (1), 0, 0.3717 (1)] at ambient conditions and transforms reversibly to a commensurately modulated structure with Z = 12 (I2/c) below 273 K. The Zn phase resembles the structures and phase transitions of Cr2P2O7. Besides descriptions of the low-temperature Co2As2O7, Ni2As2O7 and Zn2As2O7 structures as five-, three- and sixfold superstructures of the thortveitite-type basic structure, the superspace approach can also be applied to descriptions of all the commensurate structures. In addition to the ternary M 2As2O7 phases, the quaternary phase (Ni,Co)2As2O7 was prepared and structurally characterized. In contrast to the previously published crystal structure of the mineral petewilliamsite, which has the same idealized formula and has been described as a 15-fold superstructure of the thortveitite-type basic structure in space group C2, synthetic (Ni,Co)2As2O7 can be considered as a solid solution adopting the α-Ni2As2O7 structure type. Differences of the two structure models for (Ni,Co)2As2O7 are discussed.

Die Kristallstrukturen der isotypen Verbindungen Ba3[MoN4] und Ba3[WN4] / The Crystal Structures of the Isotypic Compounds Ba3[MoN4] and Ba3[WN4]

1991 ◽  
Vol 46 (5) ◽  
pp. 566-572 ◽  
Author(s):  
Axel Gudat ◽  
Peter Höhn ◽  
Rüdiger Kniep ◽  
Albrecht Rabenau
Keyword(s):  
Transition Metals ◽  
Single Crystal ◽  
Crystal Structures ◽  
Structure Type ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ternary Compounds ◽  
The Third

The isotypic ternary compounds Ba3[MoN4] and Ba3[WN4] were prepared by reaction of the transition metals with barium (Ba3N2, resp.) under nitrogen. The crystal structures were determined by single crystal X-ray diffraction: Ba3[MoN4] (Ba3[WN4]): Pbca; Z = 8; a = 1083.9(3) pm (1091.8(3) pm), b = 1030.3(3) pm (1037.5(3) pm), c = 1202.9(3) pm (1209.2(4) pm). The structures contain isolated tetrahedral anions [MN4]6- (M = Mo, W) which are arranged in form of slightly distorted hexagonal layers and which are stacked along [010] with the sequence (···AB···). Two of the three Ba atoms are situated between, the third one is placed within the layers of [MN4]-groups. In this way the structures can be derived from the Na3As structure type.

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