Sulfur hexafluoride geometry

A molecule with a steric number of 6 requires six hybrid orbitals arranged in octahedral geometry. In Chapter 9, sulfur hexafluoride appears as the primary example of a molecule with a steric number of 6 (Figure ). Six equivalent orbitals for sulfur can be constmcted for the inner sulfur atom by combining the 3. S, the three 3 p,... 

Electron affinity of sulfur hexafluoride was studied using various density functionals and systematically expanded basis sets with polarization function exponents optimized in molecular environment, /-type polarization functions were found necessary to ensure convergence of both geometry and electron affinity. The ion was found to have octahedral symmetry, and the smallest value of electron affinity is only 1.40 eV (1.6 eV with zero-point energy correction). 

The central atoms of some molecules have six electron pairs, and the geometries are then related to the octahedron. A simple example is sulfur hexafluoride (SFg). 

The hybridization of one s orbital, three p orbitals, and two d orbitals results in sp tf hybrid orbitals, as shown in Figure 10.12a a. The six sp d hybrid orbitals have an octahedral geometry, shown in Figure 10.12b a. As an example of sp d hybridization, consider sulfur hexafluoride, SF5. The sulfur atom bonds to six fluorine atoms by overlap between the sp d hybrid orbitals on sulfur and p orbitals on the fluorine atoms ... 

Hexacoordinate, hypervalent sulfur fluorides have an octahedral geometry that is symmetrical for SF6, the fluorines of which appear as a sharp singlet at +50 ppm, as do those of SeF6 (+54 ppm) and TeF6 (-56 ppm) (Scheme 7.22). NMR data for other molecular hexafluorides are also available in a recent review.5... 

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