T-shaped molecule

As an example of the different combinations arising as couplings over several bonds are studied we note in passing that VF F across chlorine in the T shaped molecule C1F3 varies from 444 Hz in the gaseous state to 420 Hz in CC14 and 426.3 HzinCCl3F68>. 

C1FS. where the T-shaped molecule has a bent cross to the T ... 

Unshared pairs of electrons will occupy bond positions. Thus the nitrogen in the ammonia molecule may be considered to occupy the center of a tetrahedron with a pair of unshared electrons at one corner (Fig. 3-9), and the water molecule may be regarded as a tetrahedron with unshared pairs at two corners. Similarly the TeCl (pyramid) and C1F3 (T-shaped) molecules may be related to the trigonal bipyramid, and the IF molecule to the octahedron. 

As shown in Figure 4, IF3 has a polymeric structure based on planar T-shaped molecules [F-I-F = 160.3(2)°]. Intermolecular interactions to two adjacent molecules occur, which result in an unusual planar pentagonal coordination geometry around the iodine atom this is quite unlike that seen forBrFj or CIF3.1 ... 

Only at the former structure does the lack of s orbital interaction allow them to be degenerate. The destabilisation energy due to s orbital interaction of these components increases as the distortion from D3 , increases, crudely speaking simply because they become less like the e species function at the geometry which has no s orbital interaction. Since the sum total s orbital destabilisation interaction with these flj combinations remains constant, if 2a and 4uj increase in s orbital destabilisation energy then 3 must decrease in energy to counterbalance this effect, s-p mixing of this type was a process which Walsh did not consider and thus the T shape molecule is markedly absent from his scheme.)... 

For systems where the lowest two p manifold orbitals of Fig. 6 are doubly occupied we may readily show that the T shape molecule is not favoured. The quadratic term is independent of angle (6 S ) but the quartic term is — 4 7 Sj [4 cos 0 +... 

Low-temperature X-ray diffraction data show that solid CIF3 contains discrete T-shaped molecules, but in solid BrF3 and IF3 there are inter-molecular X—F X bridges resulting in coordination spheres not unlike those in [BrF4] and [IF5] A... 

Our infrared spectral data suggest no gross structural changes occur in going from solution to the solid state. Although neither our infrared nor other data provide direct information concerning the molecular structure, the T-shaped molecule shown below... 

Fig. 5.27 Dependence of the cylinder shape and wall thickness on the number of the lateral chains a double-wall cylinders of the T-shaped molecule 87 and b single-wall structure of X-shaped bolaamphiphiles 88/6 [159]. Reproduced from Ref. [181] by permission of The Royal Society of Chemistry...

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