Electron diffraction bond lengths

Electron Diffraction.— Bond-length and bond-angle data have become available for trifluoromethanethiol, phenyl vinyl sulphide, dimethyl disulphide, ethyl methyl disulphide, dimethyl sulphurdi-imide, and benzenesulphonyl chloride. ... 

The average bond lengths determined for some transition metal dichlorides by electron diffraction the length of the vertical bar indicates experimental uncertainty the line connect the data points for CaQ2> MnQ2 and ZnQj... 

The X-ray diffraction pattern is photographed and computer software is used to calculate the positions of the particles within the lattice. This can be used to generate an electron density map (Figure 4.10) of the molecule in a molecular lattice. Each contour line connects points of the same electron density. Bond lengths and bond angles of the molecule may be obtained from the electron density map. 

As in the case of ions we can assign values to covalent bond lengths and covalent bond radii. Interatomic distances can be measured by, for example. X-ray and electron diffraction methods. By halving the interatomic distances obtained for diatomic elements, covalent bond radii can be obtained. Other covalent bond radii can be determined by measurements of bond lengths in other covalently bonded compounds. By this method, tables of multiple as well as single covalent bond radii can be determined. A number of single covalent bond radii in nm are at the top of the next page. 

In Figure 2 the bond lengths and internal bond angles are given for some of the simple azines. Gas-phase electron diffraction, microwave spectroscopy, or the two techniques in combination, provided the results on compounds which were sufficiently volatile but with insufficient tendency to crystallize at accessible temperatures X-ray diffraction provided the remainder. 

Structural parameters and interatomic distances derived from electron diffraction (7) (77JST(42)l2i) and X-ray diffraction (8) studies (76AX(B)3178) provide unequivocal evidence that pyrazine is planar with >2a symmetry. There is an increased localization of electron density in the carbon-nitrogen bonds, with carbon-carbon bonds being similar in length to those in benzene. ... 

Section 4.04.1.2.1). The spectroscopic and the diffraction results refer to molecules in different vibrational quantum states. In neither case are the- distances those of the hypothetical minimum of the potential function (the optimized geometry). Nevertheless, the experimental evidence appears to be strong enough to lead to the conclusion that the electron redistribution, which takes place upon transfer of a molecule from the gas phase to the crystalline phase, results in experimentally observable changes in bond lengths. 

Azetidine itself has been studied by electron diffraction, which reveals a non-planar structure (Figure 1) (73CC772). The enhanced length of the bonds reflects the strain in the ring and the angle between the CCC and CNC planes of 37° is similar to that found for cyclobutane (35°), but quite different from that for oxetane (4°). 

The most stable conformation of cyclohexane is the chair. Electron diffraction studies in the gas phase reveal a slight flattening of the chair compared with the geometry obtained when tetrahedral molecular models are used. The torsion angles are 55.9°, compared with 60° for the ideal chair conformation, and the axial C—H bonds are not perfectly parallel but are oriented outward by about 7°. The length of the C—C bonds is 1.528 A, the length of the C—H bonds is 1.119 A, and the C—C—C angles are 111.05°. ... 

TABLE 1. Bond lengths (rg) and bond angles (ra) of thionyl halides from electron diffraction... 

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