Hybrid orbitals, creation

Although the Lewis theory has been useful in our discussion of chemical bonding, some cases require more sophisticated approaches. One such approach involves the familiar s, p, and d atomic orbitals, or mixed-orbital types called hybrid orbitals. A second approach involves the creation of a set of orbitals that belongs to a molecule as a whole. Electrons are then assigned to these molecular orbitals. 

The transition of compound [1] to compound D changes the orbital hybridization of carbon number 5 from sp to sp. This transition is extremely difficult primarily because of the creation of eclipsing interactions between the substituents on carbons number 5 and 6. In compound [11 there are no such interactions the carbonyl oxygen is not eclipsing any substituents on adjacent carbon atoms. In compound D however, the hydroxyl group is eclipsing the hydrogen on carbon number 5. This is illustrated as Compound [i]... 

Since the latter effect is much weaker than the former, we can neglect the hole hybridization and concentrate on the bond creation aspect of d orbital participation. 

Atoms with four sp hybrid atomic orbitals are referred to as sp hybridized, or as having a hybridization state of sp. A diagram depicting this hybridization shows the creation of four orbitals of equal energy. 

The 3B premise provides an alternative view on the reconstruction suggesting that O, N, and C tend to find their own environment to form the tetrahedron with bond and nonbond creation. Tetrahedron bond formation drives the radial and the subsequent clock reconstruction on the O-Rh(OOl) surface. Meanwhile, the 0 transits into an 0 with sp-orbital hybridization. The ip-orbital hybridization also holds for the C and N when they react with the Ni(OOl) surface. The electrostatic... 

In metals, the electron density behaves somewhat like a fluid and tends to smooth out the surface relief created on cleavage. As a result, electronic surface dipoles appear in the surface region which cause inward displacements of surface atomic cores, i.e., relaxation. A qualitatively different case is found at semiconductor surfaces. A terminated semiconductor crystal contains on its surface so-called dangling bonds which originate from hybrid sp -orbitals of surface atoms. Upon their saturation the creation of new bonds between adjacent surface atoms leads to a lowering of the free surface energy. Such a rearrangement causes shifts of the atoms in the surface plane, i.e., a reconstruction. 

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