منابع مشابه
Influence of Substituents on Bond Lengths
Pseudopotential SCF calculations for YaC-X, Y =H, F; X=H, F, CI, PH2, PF2 and a simple model, simulating the substituents by a homogeneous, electric field, are presented in order to rationalize the substitution effect on the C-X bond.
متن کاملWeaker Bonds with Shorter Bond Lengths
One of the paradigms of chemistry predicts that the shorter the bond of a given type is always the stronger bond. Although this qualitatively holds for many compounds, there exists no general proof that this is always correct. Here, we discuss molecules, for which longer bonds lead to stronger rather than weaker bonds. This is possible by introducing the local mode stretching force constants as...
متن کاملMetal-metal bond lengths in complexes of transition metals.
In complexes of the transition metals containing clusters of metal atoms the cobalt-cobalt bond lengths are almost always within 1 pm of the single-bond value 246 pm given by the enneacovalent radius of cobalt, whereas most of the observed iron-iron bond lengths are significantly larger than the single-bond value 248 pm, the mean being 264 pm, which corresponds to a half-bond. A simple discussi...
متن کاملOn Heteroaromaticity of Nucleobases. Bond Lengths as Multidimensional Phenomena
Three hundred and nine carbon-carbon, carbon-nitrogen, and carbon-oxygen pi-bond lengths in high precision crystal structures of 31 purine and pyrimidine nucleobases were related to the Pauling pi-bond order, its analogues corrected to crystal packing effects, the numbers of non-hydrogen atoms around the bond, and the sum of atomic numbers of the bond atoms. Principal Component Analysis (PCA) a...
متن کاملDetermination of accurate, mean bond lengths from radial distribution functions.
The mean bond length d between a central atom and its nearest neighbors can be estimated from the position of the first peak in the radial distribution function g(r). However, as we demonstrate here, this estimate does not allow one to deduce temperature-induced changes in d. Instead, skewness has to be included into the analysis, which can be achieved, for example, via the skew normal distribu...
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ژورنال
عنوان ژورنال: Acta Crystallographica
سال: 1956
ISSN: 0365-110X
DOI: 10.1107/s0365110x56000851