The crystal structure of hexam ethylenetetramine I. X -ray studies at 298, 100 and 34 °K

1963 ◽  
Vol 273 (1355) ◽  
pp. 435-454 ◽  
Keyword(s):  
Room Temperature ◽  
Three Dimensional ◽  
Molecular Crystals ◽  
Lattice Vibrations ◽  
Neutron Data ◽  
Weighted Mean ◽  
X Ray ◽  
Rotational Oscillation ◽  
Direct Support ◽  
Oscillation Correction

On account of its cubic molecular and crystal symmetry, hexamethylenetetramine is a key substance in the study of the lattice vibrations of molecular crystals; its anisotropic atomic-vibration amplitudes have been determined at 298, 100 and 34 °K from three-dimensional single crystal X-ray data. Two independent sets of experiments were done with Cu and Mo radiation; these led to results in very close agreement with one another (and with results derived from previous X-ray and neutron data at room temperature). Typical final discrepancy factors obtained from full-matrix least-squares refinements are 3.4 % for 95 Mo reflexions and 6.3 % for 44 Cu reflexions at 34 °K. The studies at the three temperatures provide direct support for the rotational-oscillation correction for atomic co-ordinates. The corrected weighted-mean dimensions from eight determinations are C—N = 1.476 ± 0.002 Å, ∠N—C—N = 113.6 ± 0.2°, ∠C—N—C = 107.2 ± 0.1°, and from the neutron study C—H = 1.088 ± 0.011 Å. The compact arrangement of molecules in the crystal is described.

The Atomic Order in Guinier-Preston Zones of Aluminum-Silver Alloys

1963 ◽  
Vol 7 ◽  
pp. 1-13 ◽  
Author(s):  
Volkmar Gerold ◽  
Heinz Auer ◽  
Winfried Merz
Keyword(s):  
Room Temperature ◽  
Three Dimensional ◽  
Miscibility Gap ◽  
X Rays ◽  
Atomic Order ◽  
Zone Size ◽  
X Ray ◽  
Angle Scattering ◽  
Diffraction Patterns ◽  
Step Quenching

AbstractThe formation of the spherical Guinier—Preston zones in an aluminum-silver alloy is governed by a metastable miscibility gap, which consists of two different sections. The lower section occurs below 170°C (η state), the higher section up to 420°C (∊ state). The zones in the two sections differ in their silver concentration and in their atomic order. To prove the change in order, a combination of X-ray small-angle scattering and electric resistivity measurements was used. As the resistivity depends on the zone size and the atomic order, the change in order can be found when the zone size is known. This size was measured by the X-ray technique. To complete the results, X-rays ingle-crystal diffraction patterns with monochromatic radiation were taken at different stages. According to these patterns, three different states must be distinguished.The η′ state exists at room temperature after quenching from 550°C. The silver atoms prefer a layered arrangement in the zones, which is not very stable. It is destroyed after short annealings above 100°C. The η state is developed during annealing below 170°C. A three-dimensional atomic order is built up with increasing zone size, which results in a marked decrease in the resistivity. For the ∊ state (above 170°C), a nearly random atomic distribution exists. Step-quenching experiments prove that the ordered η state can also be developed at room temperature.

Structural Systematics of 2/4-Nitrophenoxide Complexes of Closed-Shell Metal Ions. VII Acid Salts of the 4-Nitrophenoxides of Group 2

1998 ◽  
Vol 51 (8) ◽  
pp. 785 ◽  
Author(s):  
Jack M. Harrowfield ◽  
Raj Pal Sharma ◽  
Brian W. Skelton ◽  
Allan H. White
Keyword(s):  
Room Temperature ◽  
Calcium Salt ◽  
Three Dimensional ◽  
Closed Shell ◽  
The Other ◽  
X Ray ◽  
C 23 ◽  
Structure Determinations ◽  
Group 2 ◽  
Acid Salts

Room-temperature single-crystal X-ray structure determinations are recorded for a number of Group 2 4-nitrophenoxide acid salts, variously hydrated M(4-np)2.x(4-npH).yH2O. Ca(4-np)2.2(4-npH).8H2O is monoclinic, P 21/n, a 30·52(1), b 10·027(1), c 23·65(2) Å, β 116·3(5)°, Z = 8, conventional R on |F| being 0·058 for No 5092 independent ‘observed’ (I > 3s(I)) reflections. Sr(4-np)2.2(4-npH).8H2O, based on a subcell of the former, is monoclinic, P 21/c, a 15·576(5), b10·081(6), c 24·20(2) Å, β 117·99(5)° , Z = 4, R 0·054 for No 2908. Ba(4-np)2.2(4-npH).4H2O is orthorhombic, Fdd2, a 28·01(1), b 19·90(1), c 10·692(7)Å, Z = 8, R 0·028 for No 1967. The strontium array (and that of the calcium salt developed from it) may be represented as [(H2O)6Sr(4-npH.4-np)] (4-npH.4-np), a neutral ligand being unsymmetrically chelated to the strontium through the nitro group, with a quasi-parallel counter ion hydrogen-bonded to it by phenoxide confrontation. The other two 4-np residues make up a similar phenoxide-confronting pair (4-npH.4-np), the hydrogen being more intimately associated with one moiety. The barium salt is also an interesting array: the 10-coordinate barium lies on a crystallographic 2 axis, in an environment of two pairs of symmetry-related nitro-chelating ligand anions, and a pair of nitro-O coordinating neutral 4-npH ligands; the whole [(H2O)4Ba(4-np)2(4-npH)2] array may be envisaged as a single neutral (super)molecule. Hydrogen bonds between confronting phenoxides of the neutral 4-npH components of the parent and the 4-np- components of neighbouring molecules link the whole into a three-dimensional array.

A fourfold interpenetrating diamond-like three-dimensional zinc(II) coordination polymer: synthesis, crystal structure and physical properties

2019 ◽  
Vol 75 (5) ◽  
pp. 504-507 ◽  
Author(s):  
Hui-Ru Chen
Keyword(s):  
Crystal Structure ◽  
Room Temperature ◽  
Three Dimensional ◽  
Fluorescence Emission ◽  
Crystal Structure Analysis ◽  
The Novel ◽  
X Ray Diffraction ◽  
Metal Compounds ◽  
X Ray ◽  
Coordination Framework

Excellent fluorescence properties are exhibited by d 10 metal compounds. The novel three-dimensional ZnII coordination framework, poly[[{μ2-bis[4-(2-methyl-1H-imidazol-1-yl)phenyl] ether-κ2 N 3:N 3′}(μ2-furan-2,5-dicarboxylato-κ2 O 2:O 5)zinc(II)] 1.76-hydrate], {[Zn(C6H2O5)(C20H18N4O)]·1.76H2O} n , has been prepared and characterized using IR spectroscopy, elemental analysis and single-crystal X-ray diffraction. The crystal structure analysis revealed that the compound exhibits a novel fourfold interpenetrating diamond-like network. This polymer also displays a strong fluorescence emission in the solid state at room temperature.

A three-dimensional CdIIcoordination framework: poly[di-μ2-aqua-{μ2-1,4-bis[(1H-1,2,4-triazol-1-yl)methyl]benzene-κ2N4:N4′}di-μ3-terephthalato-κ3O:O′:O′′-dicadmium(II)]

2014 ◽  
Vol 70 (11) ◽  
pp. 1025-1028
Author(s):  
Hong Shen
Keyword(s):  
Solid State ◽  
Thermogravimetric Analysis ◽  
Room Temperature ◽  
Three Dimensional ◽  
Fluorescence Emission ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
Strong Fluorescence ◽  
X Ray ◽  
Methyl Benzene

The title CdIIcoordination polymer, [Cd(C10H8O4)(C12H12N6)0.5(H2O)]n, has been obtained by the hydrothermal method and studied by single-crystal X-ray diffraction, elemental analysis, thermogravimetric analysis, IR spectroscopy and fluorescence spectroscopy. The compound forms a novel three-dimensional framework with 3,8-connected three-dimensional binodal {4.52}2{42.510.612.7.83} topology. An investigation of its photoluminescence properties shows that the compound exhibits a strong fluorescence emission in the solid state at room temperature.

Zeolite Rho Loaded with Methylamines. III. Trimethylamine Loadings

1997 ◽  
Vol 53 (3) ◽  
pp. 444-450 ◽  
Author(s):  
C. Weidenthaler ◽  
R. X. Fischer ◽  
L. Abrams ◽  
A. Hewat
Keyword(s):  
Data Collection ◽  
Neutron Diffraction ◽  
Diffraction Analysis ◽  
Room Temperature ◽  
Methyl Groups ◽  
Neutron Data ◽  
Rietveld Refinements ◽  
X Ray ◽  
Deuterated Sample ◽  
Zeolite Rho

Samples of two differently prepared zeolites rho loaded with different amounts of trimethylamine (TMA) were studied in their hydrated and dehydrated forms by X-ray and neutron diffraction experiments. Both zeolites are partially dealuminated, as indicated by nonframework Al, which is assumed to be Al2O3 or AlOOH. Series I was prepared from dry-calcined NHn-rho at 873 K, series II from steam-calcined NHn-rho at 773 K. The samples were loaded with different amounts of deuterated TMA. Rietveld refinements yielded the following results for series I: (1) H3.8(H-TMA)5Cs0.2Al9 Si39O96.Al2O3.22H2O, X-ray data collection at room temperature, Im\overline 3m, a = 15.0542 (2) Å, R wp = 0.094; (2) composition as in (1) (anhydrous), neutron data collection at 5 K of dehydrated and deuterated sample, Im3m, a = 15.0467 (4) Å, R wp = 0.034. Series II: (3) H0.3(H-TMA)5Cs0.7Al6Si42O96.2.5Al2O3.22H2O, X-ray data collection at room temperature, Im\overline 3m, a = 15.0574 (2) Å, R wp = 0.118; (4) composition as in (3) (anhydrous), neutron data collection at 5 K of dehydrated and deuterated sample, lm\overline 3m, a = 15.0761 (5) Å, R wp = 0.037. In all determinations the TMA molecules reside with the N and H (D in neutron diffraction analysis) atoms on the central axes (x, 0, 0) pointing towards the center of the single eight-ring, whilst the three methyl groups point away to the center of the \alpha-cage.

scholarly journals The synthesis, structure and photoluminescence property of a novel 3D supramolecular compound based on mixed ligands of 8-hydroxy-quionline-5-sulfonate and ethylenediamine

2011 ◽  
Vol 76 (11) ◽  
pp. 1497-1504 ◽  
Author(s):  
Ying Wang ◽  
Changfu Zhuang ◽  
Chunhua Wu ◽  
Jiayan Zhang ◽  
Wang Li ◽  
...  
Keyword(s):  
Room Temperature ◽  
Three Dimensional ◽  
Photoluminescence Property ◽  
Supramolecular Network ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mixed Ligands ◽  
Structure Solution ◽  
Hydroxy Quinoline ◽  
Hybrid Coordination

A new organic-inorganic hybrid coordination compound ZnQS (en)?2H2O (1) in which two different organic ligands, ethylenediamine (en) and 8-hydroxy-quinoline-5-sulfonic acid (H2QS) coordinate with zinc ions, has been synthesized via the evaporation method and characterized by single crystal X-ray diffraction analysis, IR spectroscopy and thermogravimetric analysis (TGA). The structure solution showed that compound 1 displays a three-dimensional supramolecular network by synergic linkage of hydrogen and coordinated bonds. Moreover, compound 1 exhibits intense photoluminescence at 513 nm excited at 396 nm in the solid state at room temperature.

Investigation into the Crystal Structure of the Perovskite Lead Hafnate, PbHfO3

1998 ◽  
Vol 54 (1) ◽  
pp. 18-28 ◽  
Author(s):  
D. L. Corker ◽  
A. M. Glazer ◽  
W. Kaminsky ◽  
R. W. Whatmore ◽  
J. Dec ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Room Temperature ◽  
Lead Zirconate ◽  
Crystal Structure Analysis ◽  
Temperature Structure ◽  
X Ray Diffraction ◽  
Neutron Data ◽  
X Ray

The room-temperature crystal structure of the perovskite lead hafnate PbHfO3 is investigated using both low-temperature single crystal X-ray diffraction (Mo Kα radiation, λ = 0.71069 Å) and polycrystalline neutron diffraction (D1A instrument, ILL, λ = 1.90788 Å). Single crystal X-ray data at 100 K: space group Pbam, a = 5.856 (1), b = 11.729 (3), c = 8.212 (2) Å, V = 564.04 Å3 with Z = 8, μ = 97.2 mm−1, F(000) = 1424, final R = 0.038, wR = 0.045 over 439 reflections with F >1.4σ(F). Polycrystalline neutron data at 383 K: a = 5.8582 (3), b = 11.7224 (5), c = 8.2246 (3) Å, V = 564.80 Å3 with χ2 = 1.62. Although lead hafnate has been thought to be isostructural with lead zirconate, no complete structure determination has been reported, as crystal structure analysis in both these materials is not straightforward. One of the main difficulties encountered is the determination of the oxygen positions, as necessary information lies in extremely weak l = 2n + 1 X-ray reflections. To maximize the intensity of these reflections the X-ray data are collected at 100 K with unusually long scans, a procedure which had previously been found successful with lead zirconate. In order to establish that no phase transitions exist between room temperature and 100 K, and hence that the collected X-ray data are relevant to the room-temperature structure, birefringence measurements for both PbZrO3 and PbHfO3 are also reported.

Tetrabutylammonium Salts of 2-Nitropropane, Cyclopentadiene and 9-Ethylfluorene: Crystal Structures and Use in Anionic Polymerization

1995 ◽  
Vol 50 (3) ◽  
pp. 415-422 ◽  
Author(s):  
Manfred T. Reetz ◽  
Stephan Hütte ◽  
Richard Goddard
Keyword(s):  
Anionic Polymerization ◽  
Room Temperature ◽  
Ion Pairs ◽  
Three Dimensional ◽  
Star Polymers ◽  
X Ray ◽  
Dimensional Network ◽  
Acidic Compounds ◽  
Cyclopentadienyl Anion ◽  
Special Case

Reaction of the CH-acidic compounds 2-nitropropane, cyclopentadiene and 9-ethylfluorene with HON (nBu)4 affords the corresponding tetrabutylammonium salts in crystalline form, which have been characterized by X -ray structure analysis. The nitrostabilized salt is not a “naked ” anion (real carbanion). Rather, the α-methylene entities of the N+(nBu)4 cations form relatively strong hydrogen bonds with the O -atom s of the nitronateanion, forming dimers in a three-dimensional network. In solution dimers in the form of supramolecular ion pairs exist. In contrast, the cyclopentadienyl anion appears to be a real carbanion, since anion and cation do not interact with one another via H -bonding. The structure of the N+(nBu)4 salt of the 9-ethylfluorenyl anion is a special case in that closer contacts between cation and anion occur, which may be indicative of unusual [CH ··· C]- bonding. All three salts function as initiators in the metal-free anionic polymerization of acrylates and methacrylates at room temperature. In the case of tetrabutylammoniumcyclopentadienide, star polymers are formed.

A twofold interpenetrating three-dimensional CdIIcoordination framework: poly[[μ2-1,3-bis(2-methyl-1H-imidazol-1-yl)benzene](μ3-5-nitrobenzene-1,3-dicarboxylato)cadmium(II)]

2014 ◽  
Vol 70 (12) ◽  
pp. 1138-1142 ◽  
Author(s):  
Le Li ◽  
Jian-Qing Tao
Keyword(s):  
Thermal Analysis ◽  
Solid State ◽  
Ir Spectroscopy ◽  
Room Temperature ◽  
Three Dimensional ◽  
Pentagonal Bipyramid ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Coordination Framework

A twofold interpenetrating three-dimensional CdIIcoordination framework, [Cd(C8H3NO6)(C14H14N4)]n, has been prepared and characterized by IR spectroscopy, elemental analysis, thermal analysis and single-crystal X-ray diffraction. The asymmetric unit consists of a divalent CdIIatom, one 1,3-bis(2-methyl-1H-imidazol-1-yl)benzene (1,3-BMIB) ligand and one fully deprotonated 5-nitrobenzene-1,3-dicarboxylate (NO2-BDC2−) ligand. The coordination sphere of the CdIIatom consists of five O-donor atoms from three different NO2-BDC2−ligands and two imidazole N-donor atoms from two different 1,3-BMIB ligands, forming a distorted {CdN2O5} pentagonal bipyramid. The NO2-BDC ligand links three CdIIatomsviaa μ1-η1:η1chelating mode and a μ2-η2:η1bridging mode. The title compound is a twofold interpenetrating 3,5-connected network with the {42.65.83}{42.6} topology. In addition, the compound exhibits fluorescence emissions in the solid state at room temperature.

Synthese, Kristallstruktur und Eigenschaften von 1,1,3,3,3-Pentaamino-1-oxo- 1λ5 ,3λ5-diphosphaz-2-en, (NH2)2(O)P-N=P(NH2)3 / Synthesis, Crystal Structure, and Properties of 1,1,3,3,3-Pentaamino-1-oxo-1λ5, 3λ5-diphosphaz-2-ene, (NH2)2(O)P-N=P(NH2)3

1996 ◽  
Vol 51 (8) ◽  
pp. 1079-1083 ◽  
Author(s):  
N. Stock ◽  
W. Schnick
Keyword(s):  
Crystal Structure ◽  
Thermal Properties ◽  
Room Temperature ◽  
Three Dimensional ◽  
Intermolecular Hydrogen Bonding ◽  
Structure And Properties ◽  
X Ray ◽  
Hydrogen Bonding Interactions ◽  
Dimensional Network ◽  
Ray Methods

Coarse crystalline (NH2)2(O)P-N=P(NH2)3 is obtained from a NH3 saturated CH2Cl2 suspension of (NH2)2(O)P-N=P(NH2)3 NH4Cl at room temperature. (NH2)2(O)P-N=P(NH2)3·NH4Cl is synthesized by slow addition of Cl2(O)P-N=PCl3 to a solution of NH3 in CH2Cl2 at -78 °C. Excess NH4Cl is removed by treatment with HNEt2 followed by extraction with CH2Cl2. The crystal structure of (NH2)2(O)P-N=P(NH2)3 has been determined by single crystal X-ray methods (P21/c; a = 1462.8(3), b = 944.8(2), c = 1026.9(2) pm, β = 110.69(3)°; Z = 8). In the unit cell there are two crystallographically unique molecules. They form a three dimensional network by intermolecular hydrogen bonding interactions (N-H···N ≥ 313 pm. N-H···O ≥ 293 pm). The investigation of the thermal properties shows decomposition with evolution of NH3 above 80 °C.

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