Fluorine orbitals

Boron orbitals Molecular orbitals Fluorine orbitals... 

Chlorine orbital Oxygen orbital Fluorine orbital ... 

For zirconia with hydroxyl group of bridge type and anion fluorine, orbital connected with fluorine is absent in the forbidden gap and electrons appear in the conduction band. Thus, zirconia with anion fluorine and hydrogen on surface must be shallow doubly donor (i.e. with two donor electrons on the each defect). 

As far as the donors with lone pairs are concerned, two factors are important—the size of the lone pairs and the electronegativity of the element. If we look at the four halides (central box above) the lone pairs are in 2p(F), 3p(Cl), 4p(Br), and 5p(l) orbitals. In all cases the orbitals on the benzene ring are 2p so the fluorine orbital is of the right size and the others too large. Even though fluorine is the most electronegative, it is still the best donor. 

Fls will not combine with His because the energy of the fluorine orbital is so low. An energy mismatch also occurs between the F2S and His orbitals. The bond must form by combining the Hi6 and F2p orbitals. To produce... 

The S—F (T-bonds involve the radial 2p orbitals, and therefore the partial MO diagram that we construct for SFg focuses only on these fluorine orbitals. The wavefunctions that describe the LGOs for the Fg fragment in SFg are derived as follows. We first work out how many of the six radial 2p orbitals are unchanged under each Ojj S5Tnmetry operation. The following row of characters gives the result ... 

Overall, the orbitals used in the hybridization are the 2s, 2p and 2py orbitals of boron, comprising the familiar sp hybrids. The difference between this approach and the molecular orbital approach is that these orbitals are combined to form the hybrids before considering their interactions with the fluorine orbitals. Because the overall symmetry is trigonal planar, the resulting hybrids must have that same symmetry, so the three sp orbitals point at the three comers of a triangle, and each interacts with a fluorine p orbital to form the three a- bonds. The 2p orbital is not involved in the bonding and, according to the hybrid approach, is empty this orbital serves as an acceptor in acid-base reactions. 

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