Accurate Bragg intensities for uracil: a thermal parameter refinement
- 1 February 1969
- journal article
- Published by Walter de Gruyter GmbH in Zeitschrift für Kristallographie
- Vol. 128 (1-2), 133-147
- https://doi.org/10.1524/zkri.1969.128.1-2.133
Abstract
Accurate and extensive three-dimensional intensity data for a single crystal of uracil have been collected by diffractometry using MoK[unk] x-radiation. The average precision in the Bragg intensities is less than 2%. Secondary extinction was eliminated by powder-diffraction measurements. Multiple diffraction could not be detected. The interaction of thermal parameters with scattering factors is analyzed with a simple model. A refinement of the anisotropic thermal parameters, based on reflections for which (sinθ)/λ exceeds.648 Å−1, led to values which are significantly different from refinement based on all data. The carbon-atom parameter differences are consistent with recent studies of combined x-ray and neutron-diffraction analysis.Keywords
This publication has 8 references indexed in Scilit:
- Valence Structure from Coherent X-Ray Scattering: Fourier Difference SynthesisThe Journal of Chemical Physics, 1968
- The elimination of multiple reflection on the four-circle diffractometerActa Crystallographica Section A, 1968
- Comparative X-Ray and Neutron Diffraction Study of Bonding Effects in s -TriazineScience, 1967
- The crystal and molecular structure of 2,5-dimethyl-7,7-dicyanonorcaradieneActa Crystallographica, 1966
- Coherent X-Ray Scattering for the Hydrogen Atom in the Hydrogen MoleculeThe Journal of Chemical Physics, 1965
- New calculations of atomic scattering factorsActa Crystallographica, 1955
- The calculation of structure factors for centrosymmetric monoclinic systems with anisotropic atomic vibrationActa Crystallographica, 1955
- The crystal structure of uracilActa Crystallographica, 1954