Journal ArticleDOI
Coherent X‐Ray Scattering for the Hydrogen Atom in the Hydrogen Molecule
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In this paper, the x-ray form factors for a bonded hydrogen in the hydrogen molecule have been calculated for a spherical approximation to the bonded atom, and the corresponding complex scattering factors have also been calculated.Abstract:
The x‐ray form factors for a bonded hydrogen in the hydrogen molecule have been calculated for a spherical approximation to the bonded atom. These factors may be better suited for the least‐squares refinement of x‐ray diffraction data from organic molecular crystals than those for the isolated hydrogen atom. It has been shown that within the spherical approximation for the bonded hydrogens in H2, a least‐squares refinement of the atomic positions will result in a bond length (Re value) short of neutron diffraction or spectroscopic values. The spherical atoms are optimally positioned 0.07 A off each proton into the bond. A nonspherical density for the bonded hydrogen atom in the hydrogen molecule has also been defined and the corresponding complex scattering factors have been calculated. The electronic density for the hydrogen molecule in these calculations was based on a modified form of the Kolos—Roothaan wavefunction for H2. Scattering calculations were made tractable by expansion of a plane wave in spheroidal wavefunctions.read more
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Journal ArticleDOI
Calcium-carbohydrate bridges composed of uncharged sugars. Structure of a hydrated calcium bromide complex of α-fucose
William J. Cook,Charles E. Bugg +1 more
TL;DR: The results indicate that calcium-fucose interactions can provide an effective, sterospecific mechanism for cross-linking carbo hydrate chains and may be involved in a variety of Ca-2+-dependent agglutination and adhesion processes.
Journal ArticleDOI
NMR-spektroskopische und strukturelle charakterisierung der tri-iso-propylsilylphosphanide des calciums
TL;DR: The reaction of (1,2-dimethoxyethane-O,O′)lithium phosphanide with chloro tri-iso-propylsilylphosphane 1 as well as bis(tri-methyl silyl)amide 2 gave single crystals of 2 (monoclinic, P21/c, a = 15105(1), b = 77118(5), c = 20334(1) pm, β = 108972(6)°, Z = 4, wR2 = 00947
Journal ArticleDOI
Electron density study of urea using TDS-corrected X-ray diffraction data: quantitative comparison of experimental and theoretical results.
TL;DR: The electron-density distribution in urea, CO(NH(2))(2), was studied by high-precision single-crystal X-ray diffraction analysis at 148 (1) K.
Journal ArticleDOI
Reassessment of large dipole moment enhancements in crystals: a detailed experimental and theoretical charge density analysis of 2-methyl-4-nitroaniline.
TL;DR: Anisotropic modeling of the motion of hydrogen atoms, integral use of periodic ab initio calculations, and improved data quality are all aspects of this study that represent a considerable advance over previous work.
Journal ArticleDOI
The stereochemistry of polynuclear compounds of the main group elements [C2H5Mg2Cl3(C4H8O)3]2, a tetrameric Grignard reagent
J. Toney,Galen D. Stucky +1 more
TL;DR: In this article, the reaction of ethyl chloride with magnesium in tetrahydrofuran (THF) yields a compound which has been determined by a single crystal X-ray diffraction study to be a tetrameric Grignard reagent, [C2H5Mg2Cl3(C4H8O)3]2.
References
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Journal ArticleDOI
The Physical Nature of the Chemical Bond
TL;DR: In this article, the quantum mechanical wave functions of molecules are discussed and an attempt is made to effect a simultaneous regional and physical partitioning of the molecular density, the molecular pair density, and the molecular energy, in such a way that meaningful concepts can be associated with the density and energy fragments thus formed.
Journal ArticleDOI
Accurate Electronic Wave Functions for the H 2 Molecule
W. Kolos,Clemens C. J. Roothaan +1 more
Journal ArticleDOI
The Problem of the Normal Hydrogen Molecule in the New Quantum Mechanics
TL;DR: The solution of Schroedinger's equation for the normal hydrogen molecule is approximated by the function $C[{e}^{\ensuremath{-}\frac{z({r}_{1}+{p}_{2})}{a}}+{e^{\ensem{-]-{m{e})+{m}−m{n}−n}]$ where m is the distance of one of the electrons to the two nuclei, and r is the distances of one electron to the other electron.
Journal ArticleDOI
The Normal State of the Hydrogen Molecule
TL;DR: In this paper, a simple wave function for the normal state of the hydrogen molecule, in which both the atomic and ionic configurations are taken into account, was set up and treated by a variational method.
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