Home About us Contact
|
Home About us Contact | ||
|
|
||
Space Group C2/c (space + group_c)
Kinds of Space Group C2/c Selected AbstractsNecessary Conditions for the Formation of {111} Twins in Barium TitanateJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 11 2000Byoung-Ki Lee The experimental conditions for {111} twin formation in BaTiO3 were investigated. When BaTiO3 compacts without excess TiO2 were sintered either in an oxidizing atmosphere (air) or in a reducing atmosphere (95N2,5H2), no {111} twins formed within the BaTiO3 grains and no abnormal grain growth occurred. In contrast, many {111} twins were present within the abnormally grown grains in the excess-TiO2 -containing BaTiO3 samples sintered in air, while no twins were observed in the excess-TiO2 -containing samples sintered in 95N2,5H2. X-ray diffraction analysis showed that excess TiO2 forms a Ba6Ti17O40 phase during sintering with the space group A2/a in air and a Ba6Ti17O40,x phase with the space group C in 95N2,5H2. It appears therefore that excess TiO2 and an oxidizing atmosphere are necessary for {111} twin formation in BaTiO3. These results may also indicate that the interface structure between BaTiO3 and Ba6Ti17O40 influences the twin formation. [source] Mixed crystal of bis(,2 -N,N-di-n-butyldithiocarbamato-S,S,S,)-bis(N,N-di-n-butyldithiocarbamato-S,S,)-di-zinc(II) and bis(,2 -N,N-di-n-butyldithiopercarbamato-S,O,O,)-bis(N,N-di-n-butyldithiocarbamato-S,S,)-di-zinc(II)CRYSTAL RESEARCH AND TECHNOLOGY, Issue 10 2007F. Emmerling Abstract The title compounds Zn2[S2CN(n-C4H9)2]41 and Zn2[(S(SO)CN(n-C4H9)2)(S2CN(n-C4H9)2)]23 build mixed crystals in the ratio 0.42: 0.58. Each compound forms dimers, in which the monomer moieties are related via a two-fold axis, coinciding with that of the monoclinic space group C2/c. The lattice parameters are a = 23.581(9), b = 17.112(5), c = 16.372(9) Å, and , = 128.33(3)°. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Hydrogen bonding of modified bases involving Watson-Crick sites: Crystal structure and conformation of Benzyl 6-aminopurine-7-carboxylateCRYSTAL RESEARCH AND TECHNOLOGY, Issue 7 2006J. M. Ohrt Abstract Crystals of benzyl 6-aminopurine-7-carboxylate (C13H11N5O2) are monoclinic, space group C2/c, Z = 8, with a = 25.448 (9), b = 6.052 (1), c = 16.975 (6)Å, , = 112.05 (5)°, M = 269.27, Dm= 1.49, Dx= 1.48 g/cm3. The structure was determined from three-dimensional diffractometric data by the multisolution technique and refined to a final reliability factor of 0.068. The molecule is planar with an intramolecular hydrogen bond from one of the amino hydrogens, Ha(N6) to the keto oxygen O(10) of the acyl group. The molecules are hydrogen bonded across the center of inversion by a pair of intermolecular hydrogen bonds using the Watson-Crick sites. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Crystal structure, thermal analysis and IR spectrometric investigation of bis (2-amino-6-methyl) pyridinium sulfateCRYSTAL RESEARCH AND TECHNOLOGY, Issue 4 2006T. Guerfel Abstract The synthesis method, crystal structure determination, phase transitions studied by thermal analysis and IR spectrometric investigation of 2C6H9N2+.SO42, are reported. The compound crystallizes in the monoclinic space group C2/c (no. 15) with a = 10.5068(4) Å, b = 10.2225(5) Å, c = 14.0422(7) Å, and , = 104.489(3)°. The atomic arrangement can be described by layers built by all the components of the structure and centered by planes z = 1/4 and 3/4. The organic molecules form channels parallel to the c direction with dimensions of 4.163(1)Å and 5.148(4)Å. Thermal analysis shows that the anhydrous compound presents an irreversible weak phase transition. The IR study, based on theoretical analyses and on the literature data allows the interpretation of the IR spectrum. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Crystal structure of ,-phenoxo bridged dicopper complex: {N-[(2-hydroxylato-5-methyl)benzyl-(2,-hydroxylato-3,,5,-dimethylbenzyl)]ethyl amine dicopper(II)}CRYSTAL RESEARCH AND TECHNOLOGY, Issue 12 2002S. M. Malathy Sony Abstract The title compound crystallizes in monoclinic space group C2/c with cell parameters a = 21.404(2), b = 13.962(1), c = 17.917(1)Å, , = 124.394(2)°, V = 4418.3(6)Å3, Z = 8, Dcal = 1.193Mg/m3 and T = 293 K. The structure was solved by Patterson method and refined by full-matrix least-squares procedures to final R = 0.0882 using 5253 observed reflections. The tetra coordinated copper atom have a slight distorted square planar geometry with the Cu-Cu distance of 2.987(1)Å. The two six membered rings containing copper atom assume distorted sofa conformation. C-H,, and C-H,O type of intermolecular interactions play a role in stabilizing the crystal packing in addition to van der Waals forces. [source] A Series of Lithium Rare Earth Polyphosphates [LiLn(PO3)4] (Ln = La, Eu, Gd) and Their Structural, Optical, and Electronic PropertiesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 2 2007Jing Zhu Abstract The structural, optical, and electronic properties of a series of lithium rare earth polyphosphates [LiLn(PO3)4] [Ln = La (1), Eu (2), Gd (3)] have been investigated by means of single-crystal X-ray diffraction, elemental analyses, and spectroscopic measurements, as well as calculations of energy-band structures, density of states, and optical response functions by density functional methods. These LiLn(PO3)4 systems are monoclinic with space group C2/c and Z = 4. Their unit-cell parameters decrease as the ionic radius of Ln3+ decreases (La3+ > Eu3+ > Gd3+). Both (PO4)3, zig-zag chains and infinite chains formed by the alternate connection of LnO8 polyhedra and LiO4 tetrahedra run parallel to the b -axis in the structure. The energy-band structures, density of states, the chemical bonds, and optical properties have been investigated by density functional methods for some of the title compounds. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] A Comparative Study of the Optical and Electroluminescent Properties of EuIII Complexes with TTA and 2-(2,-Pyridyl)azoles: The Crystal Structure of [Eu(TTA)3(PBO)]EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 18 2006Li-Hua Gao Abstract Two EuIII mixed-ligand complexes, namely [Eu(TTA)3(PBO)]and [Eu(TTA)3(PBT)] [TTA = 1,1,1-trifluoro-3-(2-thenoyl)acetonato, PBO = 2-(2,-pyridyl)-1,3-benzoxazole, and PBT = 2-(2,-pyridyl)-1,3-benzothiazole], have been synthesized. [Eu(TTA)3(PBO)] has been structurally characterized by single-crystal X-ray diffraction analysis. The complex crystallizes in the monoclinic space group C2/c. The lattice parameters are a = 41.346(4), b = 10.0538(8), c = 20.3793(16) Å, , = 110.922(2)°, Z = 8. The EuIII ion is eight-coordinate, with three bidentate TTA, anions and one bidentate N,O-chelated PBO molecule. A comparative study by UV and emission spectroscopy was carried out and electroluminescent properties of the related complexes [Eu(TTA)3(PBO)] and [Eu(TTA)3(PBT)] are reported as well. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Structural Relationships in High-Nuclearity Heterobimetallic Bismuth-Oxo ClustersEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 24 2005Michael Mehring Abstract The novel heterobimetallic sodium-bismuth-oxo clusters [Bi2Na4O(OSiMe3)8] (1), [Bi10Na5O7(OH)6(OSiMe3)15]·1.5C7H8 (2·1.5C7H8), [Bi15Na3O18(OSiMe3)12]·C7H8 (3·C7H8) and [Bi14Na8O18(OSiMe3)14(THF)4]·C6H6 (4·C6H6) were prepared starting from BiCl3 and NaOSiMe3. Compound 1 crystallises in the trigonal space group Rc with the lattice constants a = 12.8844(3) Å and c = 54.6565(3) Å, compound 2·1.5C7H8 crystallises in the triclinic space group P with the lattice constants a = 15.0377(2) Å, b = 16.0373(2) Å, c = 27.8967(5) Å, , = 87.1321(6)°, , = 86.6530(7)° and , = 63.6617(6)°, compound 3·C7H8 crystallises in the monoclinic space group C2/c with the lattice constants a = 54.311(11), b = 19.846(4), c = 22.885(5) Å and , = 112.32(3)°, and compound 4·C6H6 crystallises in the trigonal space group R with the lattice constants a = 15.9786(4) Å and c = 46.8329(17) Å. The formation of M,O,M bonds results from both partial hydrolysis followed by condensation as well as from elimination of Me3SiOSiMe3 from M,OSiMe3 groups. The hexanuclear metal-oxo silanolate 1 is more conveniently synthesised by the addition of NaOSiMe3 to a toluene solution of in situ-prepared [Bi(OSiMe3)3]. The metal-oxo(hydroxo) silanolates differ significantly in composition, but show similar building units. Thermal decomposition of the metal-oxo silanolates in the solid state gave heterogeneous decomposition products containing bismuth silicates. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] One-Dimensional Oxalato-Bridged Metal(II) Complexes with 4 - Amino-1,2,4-triazole as Apical LigandEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 21 2005Urko García-Couceiro Abstract The synthesis, chemical characterization, thermal behavior and magnetic properties of six new one-dimensional oxalato-bridged metal(II) complexes of formula [M(,-ox)(4atr)2]n [MII = Cu (1), Ni (2), Co (3), Zn (4), Fe(5)] and [Cd(,-ox)(4atr)2(H2O)]n (6) (ox = oxalato dianion, 4atr = 4-amino-1,2,4-triazole) are reported. The crystal structures of 1 and 6 have been solved by single-crystal X-ray diffraction, whereas the remaining compounds have been studied by means of X-ray powder diffraction methods. Compounds 1,5 are isomorphous and crystallize in the triclinic space group P1¯ with unit cell parameters for 1 of a = 5.538(1) Å, b = 7.663(1) Å, c = 7.711(2) Å, , = 62.21(1)°, , = 73.91(1)°, , = 86.11(1)°, and Z = 1. The crystal structures are comprised of one-dimensional linear chains in which the trans -[M(4atr)2]2+ units are sequentially bridged by bis(bidentate) oxalato ligands, resulting in an octahedral O4N2 donor set. Cryomagnetic susceptibility measurements show the occurrence of antiferromagnetic intrachain interactions for 2, 3, and 5, whereas compound 1 exhibits a weak ferromagnetic coupling in agreement with the out-of-plane exchange pathway involved. The magnetic behavior of 1 and 2 is analyzed and discussed in the light of the available magneto-structural data for analogous systems. CdII complex crystallizes in the monoclinic space group C2/c with unit cell parameters of a = 16.128(2) Å, b = 6.757(1) Å, c = 11.580(2) Å, , = 104.46(1)°, and Z = 4. Its crystal structure contains one-dimensional chains in which metal centers are heptacoodinated to four oxygen atoms from two symmetry-related bis(bidentate) oxalato bridges, two endocyclic nitrogen atoms of trans -coordinated triazole ligands and one water molecule, to give a CdO4OwN2 pentagonal-bipyramidal geometry. Thermoanalytical and variable-temperature X-ray powder diffraction analyzes show that compound 6 undergoes a reversible dehydration,hydration process in which the anhydrous residue crystallizes with a different crystal lattice retaining the dimensionality of the oxalato,metal framework. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Structural redetermination, thermal expansion and refractive indices of KLu(WO4)2JOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 2 2006M. C. Pujol The crystal structure of monoclinic KLu(WO4)2 (KLuW) crystals was determined at room temperature by using single-crystal X-ray diffraction data. The unit-cell parameters were a = 10.576,(7), b = 10.214,(7), c = 7.487,(2),Å, , = 130.68,(4)°, with Z = 4, in space group C2/c. The unit-cell parameters of KLu1,xYbx(WO4)2 were determined in relation to Yb concentration. Vickers micro-indentations were used to study the microhardness of KLuW. The linear thermal expansion tensor was determined and the principal axis with maximum thermal expansion ( = 16.72 × 10,6,K,1), , was located 13.51° from the c axis. The room-temperature optical tensor was studied in the near-infrared (NIR) and visible range. The principal optical axis with maximum refractive index (ng = 2.113), Ng, was located 18.5° from the c axis at 632.8,nm. Undoped and ytterbium-doped KLuW crystals were grown by the TSSG (top-seeded-solution growth) slow-cooling method. The crystals show {110}, {}, {010} and {310} faces that basically constitue the habit of the KLuW crystals. [source] Structure determination of diclofenac in a diclofenac-containing chitosan matrix using conventional X-ray powder diffraction dataJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 2 2004Nongnuj Muangsin The structure determination of diclofenac embedded in a diclofenac-containing chitosan matrix using conventional X-ray powder diffraction data is demonstrated. It reveals that sodium diclofenac, the starting material in the preparation of a controlled-release diclofenac-containing chitosan matrix, changes to diclofenac acid in space group C2/c in the matrix. Simple methods were employed for handling the sample to obtain X-ray powder diffraction data of sufficiently high quality for the determination of the crystal structure of diclofenac embedded in chitosan. These involved grinding and sieving several times through a micro-mesh sieve to obtain a suitable particle size and a uniformly spherical particle shape. A traditional technique for structure solution from X-ray powder diffraction data was applied. The X-ray diffraction intensities were extracted using Le Bail's method. The structure was solved by direct methods from the extracted powder data and refined using the Rietveld method. For comparison, the single-crystal structure of the same drug was also determined. The result shows that the crystal structure solved from conventional X-ray powder diffraction data is in good agreement with that of the single crystal. The deviations of the differences in bond lengths and angles are of the order of 0.030,Å and 0.639°, respectively. [source] Structure, crystal growth and physical anisotropy of KYb(WO4)2, a new laser matrixJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 1 2002M. C. Pujol The crystal structure of monoclinic KYb(WO4)2 (KYbW) crystals has been refined (in space group C2/c) at room temperature by using single-crystal X-ray diffraction data. KYbW undoped crystals were grown by the TSSG (top-seeded-solution growth) slow-cooling method. The crystals show {110}, {11}, {010} and {310} faces, which basically define their habit. The linear thermal expansion tensor has been determined and the principal axis with maximum thermal expansion ( = 16.68 × 10,6,K,1), , was located 12° from the c axis. Its principal , and axes are [302], [010] and [106] directions, respectively, in the crystallographic system. The optical tensor has been studied at , = 632.8,nm at room temperature; two principal axes, Ng and Nm, are located in the ac plane, while the other, Np, is parallel to [010]. The principal axis with maximum refractive index (ng = 2.45), Ng, was located 19° from the c axis. [source] Structural study of monoclinic KGd(WO4)2 and effects of lanthanide substitutionJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 1 2001M. C. Pujol The crystal structure of monoclinic KGd(WO4)2 (KGW) has been refined at room temperature by using single-crystal X-ray diffraction data. The unit-cell parameters are a = 10.652,(4), b = 10.374,(6), c = 7.582,(2),Å, , = 130.80,(2)°, with Z = 4, in space group C2/c. The linear thermal expansion tensor has been determined and the principal axes are [302], [010] and [106]. The principal axis with maximum thermal expansion ( = 23.44 × 10,6,K,1), , was located 12° from the c axis. Undoped crystals of KGW and crystals that were partially doped by Pr, Nd, Ho, Er, Tm and Yb were grown by the top-seeding-solution growth slow-cooling method. The effect of doping on the KGW structure was observed in the cell parameters and in morphological changes. The changes in parameters follow the changes in lanthanide ionic radii. The doped crystals show {021} and {21} faces in addition to the {110}, {11}, {010}, {130} and {310} faces which basically follow the habit of the undoped KGW crystals. The development of the faces is related to the number of the most important periodic bond chains parallel to them. [source] Structural, spectroscopic, and theoretical studies of a very short OHO hydrogen bond in bis(4-(N -methylpiperidinium)-butyrate) hydrobromideJOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 5 2009bieta Bartoszak-Adamska Abstract The molecular structure of bis(4-(N -methylpiperidinium)-butyrate) hydrobromide, (MPBu)2HBr, has been characterized by single crystal X-ray diffraction, infrared and NMR spectroscopies, and by DFT calculations. The crystals of the title compound at 140,K are monoclinic, space group C2/c, with a,=,11.7118(4), b,=,7.8737(2), c,=,23.9240(8),Å3,, ,,=,90.431(3)°, V,=,2206.1(1),Å3, and Z,=,4. Two 4-(N -methylpiperidinium)-butyrate moieties are joined by a very short and centrosymmetric O.H.O hydrogen bond of 2.436(2),Å3,. The piperidine ring adopts a chair conformation with the methyl group in the equatorial and the bulky (CH2)3COO substituent in the axial position. The broad absorption band below 1500,cm,1 in the FTIR spectrum confirms the existence of a very short O,H,O hydrogen bond. The 1H and 13C NMR spectra are interpreted on the basis of 2D experiments and the calculated GIAO/B3LYP/6-31G(d,p) magnetic isotropic shielding tensors. In the optimized structure of the complex, a 4-(N -methylpiperidinium)-butyrate zwitterion interacts with a 4-(N -methylpiperidinium)-butyric acid cation forming an O,. HO hydrogen bond of 2.580,Å3,. Copyright © 2008 John Wiley & Sons, Ltd. [source] An unexpected co-crystal with a variable degree of order: 1:1 rac -1,2-cyclohexanediol/triphenylphosphine oxideACTA CRYSTALLOGRAPHICA SECTION B, Issue 6 2007Maxime A. Siegler A 1:1 co-crystal of rac - trans -1,2-C6H10(OH)2 and (C6H5)3PO has been found that is unusual because there are no strong interactions between the two kinds of molecules, which are segregated into layers. Furthermore, neither pure rac -1,2-cyclohexanediol (CHD) nor pure triphenylphosphine oxide (TPPO) has any obvious packing problem that would make the formation of inclusion complexes likely. The TPPO layers are very much like those found in two of the four known polymorphs of pure TPPO. The hydrogen-bonded ribbons of CHD are similar to those found in other vic -diol crystals. The co-crystals are triclinic (space group P), but the deviations from monoclinic symmetry (space group C2/c) are small. The magnitudes of those deviations depend on the solvent from which the crystal is grown; the deviations are largest for crystals grown from acetone, smallest for crystals grown from toluene, and intermediate for crystals grown from ethanol. The deviations arise from incomplete enantiomeric disorder of the R,R and S,S diols; this disorder is not required by symmetry in either space group, but occupancy factors are nearly 0.50 when the structure is refined as monoclinic. When the structure is refined as triclinic the deviations of the occupancy factors from 0.50 mirror the deviations from monoclinic symmetry because information about the partial R,R/S,S ordering is transmitted from one diol layer to the next through the very pseudosymmetric TPPO layer. Analyses suggest individual CHD layers are at least mostly ordered. The degree of order seems to be established at the time the crystal is grown and is unlikely to change with heating or cooling. Thermal data suggest the existence of the co-crystal is a consequence of kinetic rather than thermodynamic factors. [source] 10-Benzyl-4-oxo-2,3,4,10-tetrahydropyrimido[4,5- b]quinolin-2-iminium chloride sesquihydrate: a polarized electronic structure within a complex hydrogen-bonded sheet structureACTA CRYSTALLOGRAPHICA SECTION C, Issue 9 2010Jorge Trilleras In the title compound, C18H15N4O+·Cl,·1.5H2O, one water site is fully ordered with unit occupancy while the other, which lies close to an inversion centre in the space group C2/c, has only 0.5 occupancy. The cation exhibits bond fixation in the fused carbocyclic ring and electronic polarization in the terminal heterocyclic ring. The components are linked into complex sheets by a combination of N,H...O, N,H...Cl, O,H...O, O,H...Cl and C,H...O hydrogen bonds. [source] KBa7Mg2B14O28F5, a new borate with an unusual heptaborate group and double perovskite unitACTA CRYSTALLOGRAPHICA SECTION C, Issue 1 2010R. K. Li A new borate, potassium barium magnesium borate fluoride, KBa7Mg2B14O28F5, with a nominal 7:1 composition of BaB2O4 to KMg2F5, has been found during the growth of BaMgBO3F crystals with a KF flux. It crystallized in the space group C2/c and is composed of isolated heptaborate [B7O14]7, groups and double perovskite [Mg2O6F5]13, units. [source] Di-,-oxido-bis{bis[N,N,-bis(2-pyridylmethyl)ethane-1,2-diamine]manganese(III,IV)} tris(perchlorate) hexahydrate: clarification of an order,disorder phase transitionACTA CRYSTALLOGRAPHICA SECTION C, Issue 11 2009Anne Nielsen The title compound, [Mn2O2(C14H18N4)2](ClO4)3·6H2O, contains a mixed-valent MnIII/MnIV complex. In accordance with a previous report [Collins, Hodgson, Michelsen & Towle (1987). J. Chem. Soc. Chem. Commun. pp. 1659,1660], the structure at 295,K is best described in the space group C2/c, with the complex exhibiting twofold rotational symmetry, and with half site occupancy for one perchlorate anion and several solvent water molecules. At 180,K, the structure is ordered in the subgroup P21/n and is clearly shown to be a hexahydrate, rather than the previously reported trihydrate. The origin of the order,disorder phase transition lies in the thermal motion of the perchlorate anions. [source] Two new cobalt(II) fumarates and a redetermination of tetraaquacobalt(II) fumarate monohydrateACTA CRYSTALLOGRAPHICA SECTION C, Issue 9 2009Sándor L. Bekö Poly[triaqua-,4 -fumarato-cobalt(II)], [Co(C4H2O4)(H2O)3]n, (I), contains two symmetry-independent octahedrally coordinated Co2+ ions, both on inversion centers. One Co2+ ion is coordinated by two water molecules and four fumarate dianions, whereas the other Co2+ ion is surrounded by four water molecules and two fumarate dianions. Each fumarate dianion is bonded to three Co2+ ions, leading to a two-dimensional structure. The fumarate dianions are nonplanar; the angle between the planes of the two carboxylate groups is 54.9,(2)°. The cobalt(II) fumarate layers are connected by hydrogen bonding into a three-dimensional network. Compound (I) is not isostructural with calcium(II) fumarate trihydrate [Gupta et al. (1972). Acta Cryst. B28, 135,139]. In poly[,4 -fumarato-dimethanolcobalt(II)], [Co(C4H2O4)(CH4O)2]n, (II), the Co2+ ions are octahedrally coordinated by four fumarate dianions and two methanol molecules, leading to a three-dimensional structure. The fumarate group is planar. The Co2+ ions and the fumarate dianions both lie on inversion centers. Additionally, the one-dimensional structure of catena -poly[[[tetraaquacobalt(II)]-,2 -fumarato] monohydrate], {[Co(C4H2O4)(H2O)4]·H2O}n, (III), was redetermined at a higher resolution, and the space group C2/c was confirmed. [source] Seven 5-benzylamino-3- tert -butyl-1-phenyl-1H -pyrazoles: unexpected isomorphisms, and hydrogen-bonded supramolecular structures in zero, one and two dimensionsACTA CRYSTALLOGRAPHICA SECTION C, Issue 6 2009Juan C. Castillo 5-Benzylamino-3- tert -butyl-1-phenyl-1H -pyrazole, C20H23N3, (I), and its 5-[4-(trifluoromethyl)benzyl]-, C21H22F3N3, (III), and 5-(4-bromobenzyl)-, C20H22BrN3, (V), analogues, are isomorphous in the space group C2/c, but not strictly isostructural; molecules of (I) form hydrogen-bonded chains, while those of (III) and (V) form hydrogen-bonded sheets, albeit with slightly different architectures. Molecules of 3- tert -butyl-5-(4-methylbenzylamino)-1-phenyl-1H -pyrazole, C21H25N3, (II), are linked into hydrogen-bonded dimers by a combination of N,H...,(arene) and C,H...,(arene) hydrogen bonds, while those of 3- tert -butyl-5-(4-chlorobenzylamino)-1-phenyl-1H -pyrazole, C20H22ClN3, (IV), form hydrogen-bonded chains of rings which are themselves linked into sheets by an aromatic ,,, stacking interaction. Simple hydrogen-bonded chains built from a single N,H...O hydrogen bond are formed in 3- tert -butyl-5-(4-nitrobenzylamino)-1-phenyl-1H -pyrazole, C20H22N4O2, (VI), while in 3- tert -butyl-5-(3,4,5-trimethoxybenzylamino)-1-phenyl-1H -pyrazole, C23H29N3O3, (VII), which crystallizes with Z, = 2 in the space group P, pairs of molecules are linked into two independent centrosymmetric dimers, one generated by a three-centre N,H...(O)2 hydrogen bond and the other by a two-centre N,H...O hydrogen bond. [source] Dimorphic forms of 3,6-dinitrodurene in a single space groupACTA CRYSTALLOGRAPHICA SECTION C, Issue 4 2009José Alberto Galicia Aguilar 3,6-Dinitrodurene (1,2,4,5-tetramethyl-3,6-dinitrobenzene), C10H12N2O4, has been crystallized in two polymorphic forms which may be distinguished by their colours in the solid state. Polymorph I gives clear colourless prismatic crystals, while polymorph II crystallizes in the dark and under an inert atmosphere as irregular purple blocks. Both forms belong to the space group C2/c, with both asymmetric units containing two half-molecules. One molecule is located on an inversion centre and the other lies on a twofold axis. The polymorphism arises from different orientations of the twofold axis: in form I, this axis passes through the mid-points of two C,C bonds of the benzene ring and, as a consequence, all atoms in the asymmetric unit are in general positions. In form II, the N atoms of the nitro groups and the Cipso atoms are located on the binary axis. Comparing phases I and II, slightly different conformations are observed for the nitro substituents, while the stacking structures are very similar. [source] Hydrogen bonding and structure of Ba2Ru2Cl10O·10H2OACTA CRYSTALLOGRAPHICA SECTION C, Issue 8 2007Sihem Boufas Dibarium ,-oxido-bis[pentachloridoruthenate(IV)] decahydrate, Ba2Ru2Cl10O·10H2O, has been prepared from ruthenium(III) chloride and barium chloride in hydrochloric acid. It crystallizes in the monoclinic system (space group C2/c). The structure consists of alternating layers of [Ru2Cl10O]4, and [Ba(H2O)7]2+ complex ions along the a direction. The O atom bonded to ruthenium occupies the 4e site, with symmetry, while the other atoms occupy general 8f sites. The overall structure is held together by O,H...O hydrogen bonds and O,H...Cl dipole,dipole interactions. [source] Tetraethylammonium dihydrogenarsenate bis(arsenic acid) and 1,4-diazoniabicyclo[2.2.2]octane bis(dihydrogenarsenate) arsenic acid: hydrogen-bonded networks containing dihydrogenarsenate anions and neutral arsenic acid moleculesACTA CRYSTALLOGRAPHICA SECTION C, Issue 7 2007Clare Lee The title compounds, (C8H20N)[H2AsO4][H3AsO4]2, (I), and (C6H14N2)[H2AsO4]2[H3AsO4], (II), are unusual salts containing organic cations, dihydrogenarsenate anions and neutral arsenic acid molecules. In (I), the dihydrogenarsenate anion lies across a twofold rotation axis in the space group C2/c, while the cation is disordered across a centre of inversion. The [H2AsO4], and H3AsO4 species interact by way of O,H...O hydrogen bonds, leading to sheets and a three-dimensional network for (I) and (II), respectively. [source] A new synthetic cobalt tellurate: Co3TeO6ACTA CRYSTALLOGRAPHICA SECTION C, Issue 8 2006Mats Johnsson Single crystals of tricobalt(II) tellurium(VI) hexaoxide, Co3TeO6, were synthesized via transport reactions using HCl as transporting agent. The compound crystallizes in the monoclinic system (space group C2/c). The Te atoms are positioned in 4b () and 8f positions, while the Co atoms are in 4e (2) and 8f positions. The structure consists of (100) oxygen layers packed in a hhchhc sequence, with TeVI in octahedral coordination and CoII in both octahedral and tetrahedral coordination. The structure contains face-sharing CoO6 octahedra, as well as edge-sharing CoO4 tetrahedra. Co3TeO6 is the first oxide that is isostructural with the ,-Li3MF6 family of compounds (M = Al, Cr, Ga, Ti and V). [source] In1.06Ho0.94Ge2O7: a thortveitite-type compoundACTA CRYSTALLOGRAPHICA SECTION C, Issue 2 2004Erick A. Juarez-Arellano A new indium holmium digermanate, In1.06Ho0.94Ge2O7, with a thortveitite-type structure, has been prepared as a polycrystalline powder material by high-temperature solid-state reaction. This new compound crystallizes in the monoclinic system (space group C2/c, No. 15). The structure was characterized by Rietveld refinement of powder laboratory X-ray diffraction data. The In3+ and Ho3+ cations occupy the same octahedral site, forming a hexagonal arrangement on the ab plane. In their turn, the hexagonal arrangements of (In/Ho)O6 octahedral layers are held together by sheets of isolated diortho groups comprised of double tetrahedra sharing a common vertex. In this compound, the Ge2O7 diortho groups lose the ideal D3d point symmetry and also the C2h point symmetry present in the thortveitite diortho groups. The Ge,O,Ge angle bridging the diortho groups is 160.2,(3)°, compared with 180.0° for Si,O,Si in thortveitite (Sc2Si2O7). The characteristic mirror plane in the thortveitite space group (C2/m, No. 12) is not present in this new thortveitite-type compound and the diortho groups lose the C2h point symmetry, reducing to C2. [source] 9-Cyano-10-methylacridinium hydrogen dinitrateACTA CRYSTALLOGRAPHICA SECTION C, Issue 5 2002Olexyj M. Huta The title compound, C15H11N2+·HN2O6,, crystallizes in the monoclinic space group C2/c with four molecules in the unit cell. The planar 9-cyano-10-methylacridinium cations lie on crystallographic twofold axes and are arranged in layers, almost perpendicular to the ac plane, in such a way that neighbouring molecules are positioned in a `head-to-tail' manner. These cations and the hydrogen dinitrate anions are linked through C,H,O interactions involving four of the six O atoms of the anion and the H atoms attached to the C atoms of the acridine moiety in ring positions 2 and 4. The H atom of the hydrogen dinitrate anion appears to be located on the centre of inversion relating two of the four O atoms engaged in the above-mentioned C,H,O interactions. In this way, columns of either anions or cations running along the c axis are held in place by the network of C,H,O interactions, forming a relatively compact crystal lattice. [source] Bis(3-nitrophenyl) disulfide forms no C,H,O hydrogen bondsACTA CRYSTALLOGRAPHICA SECTION C, Issue 10 2000Debbie Cannon In the title compound, C12H8N2O4S2, the molecules lie across twofold rotation axes in the space group C2/c. There are no intermolecular C,H,O hydrogen bonds, but the molecules are linked into chains along [001] by aromatic ,,, stacking interactions. [source] ChemInform Abstract: Actinide Tetracyanoplatinates: Synthesis and Structural Characterization with Uncharacteristic Th,NC Coordination and Thorium Fluorescence.CHEMINFORM, Issue 40 2010Branson A. Maynard Abstract The structures of the new tetracyanoplatinates (III) (monoclinic, space group C2/c, Z = 4), (IV) (orthorhombic, Pbca, Z = 8), and (VI) (tetragonal, P4/mbm, Z = 4) are determined by single crystal. [source] A New Keggin Tungstocobaltate Decorated by Zinc(II) Complex Groups: [Zn(2,2,-bipy)3]3{[Zn(2,2,-bipy)2(H2O)]2 -[HCoW12O40]2}·H2OCHINESE JOURNAL OF CHEMISTRY, Issue 6 2009Hong WANG Abstract A new organic-inorganic hybrid compound based on Keggin tungstocobaltate decorated by zinc(II) coordination groups, [Zn(2,2,-bipy)3]3{[Zn(2,2,-bipy)2(H2O)]2[HCoW12O40]2}·H2O (bipy=bipyridine), has been synthesized under hydrothermal conditions and characterized by elemental analyses, IR, TG analyses and X-ray single crystal diffraction. This compound crystallizes in the orthorhombic system, space group C2/c with a=46.966(9) ?, b=14.358(3) Å, c=26.154(5) Å, ,=,=,=90°, V=17637(6) Å3, and Z=4. The result of structure determination shows that the crystal structure is constructed from a mono-supporting Keggin tungstocobaltate polyanion {[Zn(2,2,-bipy)2(H2O)]2[HCoW12O40]2}6,, three [Zn(2,2,-bipy)3]2+ cations and one water molecule. It is interesting that [Zn(1)(2,2,-bipy)3]2+ cations are held together into a helix chain through hydrogen-bonding interactions. Additionally, the compound is stable in air and shows intense photoluminescence at room temperature. [source] An Unprecedented 2D 4f-3d-5d Multimetal-Isonicotinic Acid Complex: Synthesis, Structural Characterization and Magnetic PropertiesCHINESE JOURNAL OF CHEMISTRY, Issue 9 2008Wen-Tong CHEN Abstract A novel heterometallic metal-isonicotinic acid inorganic-organic hybrid complex [Zn0.5(H2O)]{(Hg2Cl5)- [Er(C6NO2H4)3(H2O)2]}(HgCl2)·0.5CH3OH·0.5H2O (1) has been successfully synthesized via a hydrothermal reaction and structurally characterized by single-crystal X-ray diffraction. Complex 1 crystallizes in the space group C2/c of the monoclinic system with eight formula units in a cell: a=34.165(4) Å, b=9.4692(8) Å, c=24.575(3) Å, , =115.090(5)°, V=7200(1) Å3, C18.50H21Cl7ErHg3N3O10Zn0.50, Mr=1495.25, Dc=2.759 g/cm3, T=293(2) K, µ(Mo K,) =15.954 mm,1, F(000) =5400 and R1/wR2=0.0561/0.0909 for 3157 observed reflections [I>2,(I)] and 6468 unique reflections. Complex 1 is characteristic of a novel 2D {(Hg2Cl5)[Er(C6NO2H4)3(H2O)2]} layered structure constructed from the [Er(C6NO2H4)3(H2O)2] chains interconnected by the Hg2Cl5, linkers. The 2D {(Hg2Cl5)[Er(C6NO2H4)3(H2O)2]} layers, mercury chloride and the lattice water molecules are held together via hydrogen bonds to form a three-dimensional framework with the methanol molecules and the hydrated zinc ions located in the cavities. The magnetic properties show that complex 1 exhibits antiferromagnetic-like interactions. [source] | |||||||||||||