Bond angle from electron diffraction

We conclude that the bond angle Is 180" 10" and adopt the bond distance from electron diffraction (21). Frequencies v, and v ... 

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

Fig. 3 Optimized geometries at BP86/TZ2P (BP86/SVP) of ligands 1-8. Experimental values are given in italics. Bond lengths in A, angles in degrees. Experimental values from electron diffraction taken from [5]. Experimental values from X-ray analysis taken from [6]. Experimental values from X-ray analysis taken from [7]. Experimental values top) from X-ray analysis taken from [18]. Experimental values bottom) from electron diffraction taken from [19]...

Electron diffraction measurements of gaseous 1,2,4-trioxolane point to either a C2 symmetry, as depicted at the bottom of Appendix A, or a Cj symmetry, corresponding to an envelope conformation. However, consideration of steric interactions favors the twisted chair conformation (288c) for the molecule. Table 5 presents the structural parameters derived from electron diffraction, assuming that both C—O distances are equal and that the H atoms are symmetrically placed with respect of the neighboring atoms. Assumptions on the vibrational amplitudes of the ring bonds do not affect the calculated values of Table 5, except for the H—C—H angle . ... 

The bond length and angle are those derived by Akishin et al. ( l.) from electron-diffraction data for the vapor. 

The vibrational levels are from the Raman data of Gerding et al. (3 ) and infrared spectra data of Sidorov and Sobolev (4). Bond distances and angles are from electron diffraction data by Hampson and Stosick (5). 

The valency angles, in addition to the bond distances, may be determined from electron diffraction studies and the magnitude of the bond angle may be regarded as an indication of the extent of the contribution of various valence bond structures in which the angle is different. For example, methyl wocyanide is generally considered as being a linear mole. 

The molecular structure of 1,3,5-triazine in the gas phase was determined from electron diffraction, infrared and Raman data and 4-21G force field calculations C—N bond length = 1.338 A, C—H = 1.106A, CNC bond angle = 113.9°, NCN= 126.1°, and HCN= 116.9° <86JST(147)321>. The geometries of 1,3,5-triazine and its protonated form, along with other azines, have been fully optimized at the STO-3G, 3-21G and 6-31G levels <87JST(35)135>. 

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