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X-Ray Diffraction Study of the Electron Density and Anharmonicity in K2PtCl6
Journal article

X-Ray Diffraction Study of the Electron Density and Anharmonicity in K2PtCl6

  • Restori, Renzo 1Institute of Crystallography, University of Lausanne, BSP, CH-1015 Lausanne, Switzerland
  • Schwarzenbach, Dieter 1Institute of Crystallography, University of Lausanne, BSP, CH-1015 Lausanne, Switzerland
Published in:
  • Zeitschrift für Naturforschung A. - Walter de Gruyter GmbH. - 1993, vol. 48, no. 1-2, p. 12-20
Physical and Theoretical Chemistry
Mathematical Physics
General Physics and Astronomy
English Abstract X-ray diffraction data in heavy-atom compounds may be sensitive to anharmonic atomic displacements, since the large core electron densities result in appreciable scattering amplitudes at large reciprocal distances. Since bonding electron densities may also exhibit sharp features affecting high-order reflections, they may be difficult to distinguish from anharmonic effects. We have analyzed an accurate room-temperature single-crystal X-ray data set of K2 PtCl6 using least-squares anharmonic displacement and charge density formalisms. The Hirshfeld charge density formalism, which has successfully been applied to many light-atom structures, fails to parametrize satisfactorily the data, whereas the electron densities at K and CI are easily accounted for by an anharmonic Gram-Charlier expansion to 4th order. Densities around Pt are parametrized only by a combination of anharmonicity and charge density formalisms. If economical parametrizations of the experimental data are preferred to more complicated ones, anharmonicity may be conjectured to play an important rôle while the main bonding feature consists of a preferential occupation of the 5d-orbitals of Pt with t2g symmetry.
Language
  • English
Open access status
closed
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Persistent URL
https://sonar.rero.ch/global/documents/297628
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