Ab Plane (ab + plane)

Distribution by Scientific Domains


Selected Abstracts


The influence of Pb-ion irradiation on melt-textured YBa2Cu3Ox crystals

CRYSTAL RESEARCH AND TECHNOLOGY, Issue 2 2009
I. M. Obaidat
Abstract Melt-textured YBa2Cu3Ox crystals have been irradiated along the c -axis with 208Pb56+ ions corresponding to dose matching fields, B, = 0.5 T and B, = 2.0 T. Magnetization measurements were conducted along the ab plane of the samples. The strength of pinning sites was investigated by measuring magnetization hysterisis and the saturation remanent magnetization MR at several temperatures. We have found that the pinning strength was considerably enhanced after irradiation at both doses. Interestingly, the pinning strength at a Pb-ion irradiation which corresponds to the dose matching field B, = 0.5 T, was found to be significantly larger than that at the dose matching field B, = 2.0 T at all temperatures. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Non-volatile Ferroelectric Poly(vinylidene fluoride- co -trifluoroethylene) Memory Based on a Single-Crystalline Tri-isopropylsilylethynyl Pentacene Field-Effect Transistor

ADVANCED FUNCTIONAL MATERIALS, Issue 10 2009
Seok Ju Kang
Abstract A new type of nonvolatile ferroelectric poly(vinylidene fluoride- co -trifluoroethylene) (P(VDF-TrFE)) memory based on an organic thin-film transistor (OTFT) with a single crystal of tri-isopropylsilylethynyl pentacene (TIPS-PEN) as the active layer is developed. A bottom-gate OTFT is fabricated with a thin P(VDF-TrFE) film gate insulator on which a one-dimensional ribbon-type TIPS-PEN single crystal, grown via a solvent-exchange method, is positioned between the Au source and drain electrodes. Post-thermal treatment optimizes the interface between the flat, single-crystalline ab plane of TIPS-PEN and the polycrystalline P(VDF-TrFE) surface with characteristic needle-like crystalline lamellae. As a consequence, the memory device exhibits a substantially stable source,drain current modulation with an ON/OFF ratio hysteresis greater than 103, which is superior to a ferroelectric P(VDF-TrFE) OTFT that has a vacuum-evaporated pentacene layer. Data retention longer than 5,×,104 s is additionally achieved in ambient conditions by incorporating an interlayer between the gate electrode and P(VDF-TrFE) thin film. The device is environmentally stable for more than 40 days without additional passivation. The deposition of a seed solution of TIPS-PEN on the chemically micropatterned surface allows fabrication arrays of TIPS-PEN single crystals that can be potentially useful for integrated arrays of ferroelectric polymeric TFT memory. [source]


Supramolecular aggregation in 4,4,-bipyridin-1,1,-ium dichloride, 4,4,-bipyridin-1,1,-ium dinitrate and 4,4,-bipyridin-1-ium bromide

ACTA CRYSTALLOGRAPHICA SECTION B, Issue 5 2003
Peter Abeta Iyere
4,4,-Bipyridin-1,1,-ium dichloride [C10H10Cl2N2 (I)] and 4,4,-bipyridin-1,1,-ium dinitrate [C10H10N4O6 (II)] have been prepared and the crystal structures determined at 90.0,(2),K. Molecules of (I) are linked by two chlorine-bridged, three-centered N,H,Cl hydrogen bonds into chains along the b axis. The chains are coupled by weak C,H,Cl interactions into a molecular ladder along the c direction. In (II) each nitrate is coordinated to four bipyridinium ions through the interplay of the N,H,O and C,H,O contacts, resulting in a three-dimensional zigzag sheet on the ab plane. The sheets stack along the c axis. In 4,4,-bipyridin-1-ium bromide monohydrate [C10H9N2+·Br,·H2O (III)] the bipyridinium ions are linked by three-center N,H,N, hydrogen bonds in a head-to-tail fashion to form chains along the b axis. The chains are linked by C,H,Br and C,H,OH2 into a three-dimensional framework. [source]


Z and E isomers of butenedioic acid with 2-amino-1,3-thiazole: 2-amino-1,3-thiazolium hydrogen maleate and 2-amino-1,3-thiazolium hydrogen fumarate

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 8 2010
Jain John
Maleic acid and fumaric acid, the Z and E isomers of butenedioic acid, form 1:1 adducts with 2-amino-1,3-thiazole, namely 2-amino-1,3-thiazolium hydrogen maleate (2ATHM), C3H5N2S+·C4H3O4,, and 2-amino-1,3-thiazolium hydrogen fumarate (2ATHF), C3H5N2S+·C4H3O4,, respectively. In both compounds, protonation of the ring N atom of the 2-amino-1,3-thiazole and deprotonation of one of the carboxyl groups are observed. The asymmetric unit of 2ATHF contains three independent ion pairs. The hydrogen maleate ion of 2ATHM shows a short intramolecular O,H...O hydrogen bond with an O...O distance of 2.4663,(19),Å. An extensive hydrogen-bonded network is observed in both compounds, involving N,H...O and O,H...O hydrogen bonds. 2ATHM forms two-dimensional sheets parallel to the ab plane, extending as independent parallel sheets along the c axis, whereas 2ATHF forms two-dimensional zigzag layers parallel to the bc plane, extending as independent parallel layers along the a axis. [source]


Orientational disorder in ,-cobalt(III) sepulchrate trinitrate

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 4 2010
Andreas Schönleber
The crystal structure of ,-(1,3,6,8,10,13,16,19-octaazabicyclo[6.6.6]eicosane)cobalt(III) trinitrate, [Co(C12H30N8)](NO3)3, consists of a sepulchrate moiety that serves as a macrobicyclic nitrogen cage for the Co3+ cation, which is six-coordinated by N atoms, and three nitrate anions. The Co,sepulchrate group lies on a threefold axis (site symmetry 32), as do two symmetry-related and ordered nitrate groups (site symmetry 3), with which it is connected via N,H...O hydrogen bonds [Co,N = 5.1452,(12),Å]. The third nitrate group is disordered as a result of symmetry requirements around the origin (site symmetry 32), and is further away from the Co,sepulchrate cage [Co,N = 6.3160,(8),Å]. The structure is described by applying orientational disorder over six equivalent orientations for the disordered nitrate group, which is considered as an ideal planar molecule of regular trigonal geometry with its molecular plane rotated out of the ab plane and the molecular centre of gravity slightly shifted away from the origin. This new model for disorder clearly improves a previous crystal structure determination. [source]


catena -Poly[[bis(acetonitrile-,N)manganese(II)]-bis(,-trifluoromethanesulfonato-,2O:O,)]

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 1 2010
Martin Lutz
The title compound, [Mn(CF3SO3)2(CH3CN)2]n, has an MnII cation on an inversion centre in an octahedral environment. The trifluoromethanesulfonate anions act as bridging ligands and form a one-dimensional coordination polymer in the direction of the a axis. The F atoms of the trifluoromethanesulfonate anions form layers parallel to the ab plane, but despite short intermolecular distances, no stabilizing F...F interactions are detected. The Mn,N and C,C bonds of the acetonitrile ligand are analyzed according to the Hirshfeld rigid-bond test. Renninger effects in the reflection data are considered, explored and discussed. [source]


Asymmetric ruthenium-catalysed [2+2] cycloadditions between bicyclic alkenes and chiral aryl-substituted acetylenic acyl camphorsultam alkynes

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 12 2009
Jordan D. Goodreid
The regio- and absolute stereochemistry of (7S)- N -[4-(3-thienyl)tricyclo[4.2.1.02,5]non-3-en-3-ylcarbonyl]-2,10-camphorsultam tetrahydrofuran hemisolvate, C24H29NO3S2·0.5C4H8O, and (7S)- N -[4-(4-tolyl)tricyclo[4.2.1.02,5]non-3-en-3-ylcarbonyl]-2,10-camphorsultam, C27H33NO3S, have been established. One contains a half-occupancy tetrahydrofuran solvent molecule located on a twofold axis and the other contains two crystallographically unique molecules which are nearly identical. The extended structures of both complexes can be explained via weak C,H...O interactions, which link the molecules together into two-dimensional sheets in the ab plane for the thienyl complex and ultimately into a three-dimensional structure for the tolyl derivative. The stereochemistry of both structures confirms that [2+2] cycloadditions of bicyclic alkenes and alkynes catalysed by ruthenium are exclusively exo. [source]


Trinitratobis{N,-[1-(2-pyridyl)ethylidene]isonicotinohydrazide}cerium(III): a three-dimensional cerium,organic supramolecular structure

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 7 2009
Ying-Ying Zhang
The CeIII ion in the title complex, [Ce(NO3)3(C13H12N4O)2], is 12-coordinated by six chelating nitrate O atoms and six donors (2 O and 4 N atoms) of two N,-[1-(2-pyridyl)ethylidene]isonicotinohydrazide ligands, exhibiting a bicapped pentagonal-antiprism-type coordination geometry. The title complex possesses C2 point symmetry and is located on a twofold crystallographic axis. Each molecule is linked with four surrounding molecules by four N,H...N hydrogen bonds, resulting in an extended two-dimensional layer parallel to the ab plane, while ,,, interactions between pyridine rings from neighboring complex molecules connect the two-dimensional layers into a three-dimensional cerium,organic supramolecular structure. [source]


K3(Sc0.875Nb0.125)Nb2O9H1.75: a new scandium niobate with a unique cage structure

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 5 2009
Matthew Mann
Potassium scandium niobate hydroxide, K3(Sc0.875Nb0.125)Nb2O9H1.75, is a new scandium niobate with a unique cage structure. The structure contains two non-equivalent K+ sites (3m and m2 site symmetry), one disordered Sc3+/Nb5+ site (m site symmetry), one Nb5+ site (3m site symmetry), two O2, sites (m and mm2 site symmetry) and one H+ site (m site symmetry). Both scandium and niobium have octahedral environments, which combine to form cages around potassium. One K atom lies in a cube-like cage built of seven octahedra, while the other K atom is encapsulated by an eight-membered trigonal face-bicapped prism. The cages form sheets that extend along the ab plane. [source]


The coordination polymers poly[,-4,4,-bipyridyl-di-,-formato-copper(II)] and catena -poly[[[diaqua(1-benzofuran-2,3-dicarboxylato)copper(II)]-,-1,2-di-4-pyridylethane] dihydrate]

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 5 2009
Rajesh Koner
The title compounds, [Cu(CHO2)2(C10H8N2)]n, (I), and {[Cu(C10H4O5)(C12H12N2)(H2O)2]·2H2O}n, (II), are composed of one-dimensional linear coordination polymers involving copper(II) ions and bidentate bipyridyl species. In (I), the polymeric chains are located on twofold rotation axes at (x, x, 0) and are arranged in layered zones centered at z = 0, , ½ and parallel to the ab plane of the tetragonal crystal. Weak coordination of the formate anions of one layer to the copper centers of neighboring layers imparts a three-dimensional connectivity to this structure. In (II), the polymeric chains propagate parallel to the a axis of the crystal. Noncoordinated water molecules link the chains through O,H...O hydrogen bonding in directions perpendicular to c, imparting to the entire structure three-dimensional connectivity. The metal ions adopt distorted octahedral and square-based pyramidal environments in (I) and (II), respectively. This study indicates that, under the given conditions, extended coordination involves CuII centers associating with the bipyridyl ligands rather than with the competing benzofurandicarboxylate entities. [source]


(Di- tert -butylmethylphosphane)(,2 -di- tert -butylphosphanylphosphinidene)(triphenylphosphane)platinum(0)

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 1 2009
Antoni Konitz
The crystal structure of the title compound, [Pt(C8H18P2)(C9H21P)(C18H15P)] or [(Ph3P)(tBu2PMe)Pt(,2 - tBu2PP)], contains four molecules in the asymmetric unit with slightly different conformations. The P,P distances in the tBu2PP ligands are similar for all four molecules [2.0661,(13),2.0678,(13),Å] and indicate a multiple character of the P,P bond in the tBu2PP ligand. Molecules of the asymmetric unit can be assembled into a tetrahedron that fulfils the requirements for a rhombic disphenoid. The coordination of the Pt atom in all four molecules is square planar, with r.m.s. deviations from the PtP4 planes in the range 0.03,0.05,Å. All planes of the PtP4 groups are approximately parallel to the ab plane of the unit cell. The structure represents an unusual unsymmetrical platinum phosphinidene derivative. [source]


Ba3Li2V2O7Cl4, a new vanadate with a channel structure

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 4 2008
Thomas Reeswinkel
The tribarium dilithium divanadate tetrachloride Ba3Li2V2O7Cl4 is a new vanadate with a channel structure and the first known vanadate containing both Ba and Li atoms. The structure contains four non-equivalent Ba2+ sites (two with m and two with 2/m site symmetry), two Li+ sites, two nonmagnetic V5+ sites, five O2, sites (three with m site symmetry) and four Cl, sites (m site symmetry). One type of Li atom lies in LiO4 tetrahedra (m site symmetry) and shares corners with VO4 tetrahedra to form eight-tetrahedron Li3V5O24 rings and six-tetrahedron Li2V4O18 rings; these rings are linked within porous layers parallel to the ab plane and contain Ba2+ and Cl, ions. The other Li atoms are located on inversion centres and form isolated chains of face-sharing LiCl6 octahedra. [source]


(N -{[4-(1,3-Benzothiazol-2-yl)anilino]carbonylmethyl-,O}iminodiacetato-,3O,N,O,)(1,10-phenanthroline-,2N,N,)cobalt(II) pentahydrate

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 4 2008
Guo-Wu Lin
The title compound, [Co(C19H15N3O5S)(C12H8N2)]·5H2O, has a moderately distorted octahedral coordination environment composed of two N atoms of a 1,10-phenanthroline ligand and one N and three O atoms of an N -{[4-(1,3-benzothiazol-2-yl)anilino]carbonylmethyl}iminodiacetate (ZL-52,) ligand. The ring systems of the phenanthroline and ZL-52, ligands are coplanar and the complexes pack in layers parallel to the ab plane with the rings of adjacent complexes facing one another. The layers stack along the c axis and are linked by hydrogen bonds involving the five water solvent molecules in the asymmetric unit and O atoms of the acetate groups of the ZL-52, ligand. This is believed to be the first crystal structure of a complex of a 2-(4-aminophenyl)benzothiazole ligand. [source]


Bis(5-aminotetrazole-1-acetato-,O)tetraaquacobalt(II) and catena -poly[[cadmium(II)]-bis(,-5-aminotetrazole-1-acetato-,3N4:O,O,)]

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 1 2008
Qiao-Yun Li
The CoII atom in bis(5-aminotetrazole-1-acetato)tetraaquacobalt(II), [Co(C3H4N5O2)2(H2O)4], (I), is octahedrally coordinated by six O atoms from two 5-aminotetrazole-1-acetate (atza) ligands and four water molecules. The molecule has a crystallographic centre of symmetry located at the CoII atom. The molecules of (I) are interlinked by hydrogen-bond interactions, forming a two-dimensional supramolecular network structure in the ac plane. The CdII atom in catena -poly[[cadmium(II)]-bis(,-5-aminotetrazole-1-acetato], [Cd(C3H4N5O2)2]n, (II), lies on a twofold axis and is coordinated by two N atoms and four O atoms from four atza ligands to form a distorted octahedral coordination environment. The CdII centres are connected through tridentate atza bridging ligands to form a two-dimensional layered structure extending along the ab plane, which is further linked into a three-dimensional structure through hydrogen-bond interactions. [source]


Weak C,H...N[triple-bond]C hydrogen bonds in the structures of two poly(cyano)-substituted ring systems

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 12 2007
Peter G. Jones
In benzene-1,2,3-tricarbonitrile, C9H3N3, the packing of the two independent molecules is three-dimensional and complex, involving inter alia bifurcated (C,H)2...N systems from neighbouring CH groups. In [2.2]paracyclophane-4,5,12,13-tetracarbonitrile, C20H12N4, the [2.2]paracyclophane systems display the usual distortions, namely lengthened C,C bonds and widened sp3 angles in the bridges, narrow angles in the six-membered rings at the bridgehead atoms, and flattened boat conformations of the rings. The molecules are linked by a series of C,H...N interactions to form layers parallel to the ab plane. [source]


The complex phosphate K0.92In0.46Nb0.54OPO4: a new representative of the KTiOPO4 family

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 11 2007
Artem A. Babaryk
Aliovalent K0.92In0.46Nb0.54OPO4 (KINP, potassium indium niobium oxide phosphate) features a chain structure involving corner-sharing [MO6] octahedra (M = In/Nb), which allows this compound to be recognized as a member of the KTiOPO4 (KTP) family. However, its crystallization in the polar space group P41 belonging to the 4/m Laue group generates its own subclass of KTP-related compounds. The unit cell contains 18 symmetry-independent atoms occupying general positions. The cis,cis principle of octahedral arrangement is observed for each of the separate [MO6], chains. The observed variations in the cis,cis linkage are critically important for nonlinear optical properties and distinguish the present compound from other KTP-related structures. The anionic framework adopts one-dimensional tunnels running orthogonal to the ab plane. The K+ ions are arranged in the [001] direction at a distance of c. Merohedral twinning was detected during the structure refinement. [source]


Poly­[di­aqua-,4 -oxalato-di-,6 -phos­phato-tetrazinc]

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 10 2004
You-Ju Zhong
The structure of the title compound, [Zn4(C2O4)(PO4)2(H2O)2]n, which was synthesized under hydro­thermal conditions, consists of zinc phosphate layers joined by bridging oxalate ligands to generate a three-dimensional framework. An extended zinc phosphate layer lies parallel to the ab plane and within this layer there are helical chains, composed of ZnO6 octahedra and ZnO5 square pyramids, that run parallel to the b axis and coincide with the 21 screw element. The oxalate groups sit on crystallographic inversion centers. [source]


1-Phenyl-5-(piperidino­methyl)-1H -tetrazole

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 4 2004
Alexander S. Lyakhov
In the mol­ecule of the title 1,5-disubstituted tetrazole, C13H17N5, the tetrazole and benzene rings are not coplanar, having a dihedral angle of 42.96,(5)° between them. The piperidine fragment adopts a chair conformation, and there is a non-classical intramolecular contact between the benzene H atom and the piperidine N atom. Intermolecular C,H,, interactions involving the piperidine C,H groups and the benzene rings are responsible for the formation of two-dimensional networks, extending parallel to the ab plane. These networks are linked together into a three-dimensional polymeric structure via,,, stacking interactions between the tetrazole rings of two adjacent mol­ecules. [source]


In1.06Ho0.94Ge2O7: a thortveitite-type compound

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 2 2004
Erick 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]


2,4,6-Tris­[2-(tri­methyl­silyl)­ethynyl]-1,3,5-triazene: a novel precursor to C,N two-dimensional structures

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 11 2000
John Kouvetakis
The title structure, C18H27N3Si3, consists of separate mol­ecules arranged in sheets parallel to the ab plane. In each mol­ecule, the central (CN)3 ring, the ethynyl units, and the Si atoms lie in the same plane. Typical C,C and C,N bond distances are 1.197,(5) and 1.42,(4),Å, respectively. The angles inside the (CN)3 ring range from 114,(3) to 125,(3)° and the acetyl­enic branches are nearly linear. [source]