P orbitals hybridization

The asymmetry of sp3 orbitals arises because, as noted previously, the two lobes of a p orbital have different algebraic signs, + and -. Thus, when a p orbital hybridizes with an s orbital, the positive p lobe adds to the s orbital but the negative p lobe subtracts from the s orbital. The resultant hybrid orbital is therefore unsymmetrical about the nucleus and is strongly oriented in one direction. 

FIGURE 3.16 Three common hybridization schemes shown as outlines of the amplitude of the wavefunction and in terms of the orientations of the hybrid orbitals, (a) An s-orbital and a p-orbital hybridize into two sp hybrid orbitals that >oint in opposite direc tions, forming a linear molecular shape, (b) An s-orbital and two p-orbitals can blend together to give three ip hybrid orbitals that point to the corners of an equilateral triangle, (c) An s-orbital and three p-orbitals can blend together to give four sp hybrid orbitals that point to the corners of a tetrahedron. 

Element Pauling 4 Sanderson X Allred- Rochow Xttv1 Allen X p Orbital hybrid Pauling scale Volts b Volfs/ electron... 

Element Pauling Sandersan x% Allred-Rachow v d Allen p Orbital hybrid Pauling Volts b Volts/ electron... 

The number of hybrid orbitals formed is always the same as the total number of s and p orbitals hybridized. 

One s and three p orbitals hybridize to form four sp orbitals. According to VSEPR, a tetrahedral shape minimizes repulsion between the orbitals. 

We have seen that hybridization neatly explains bonding that involves and p orbitals. For elements in the third period and beyond, however, we cannot always account for molecular geometry by assuming that only. y and p orbitals hybridize. To understand the formation of molecules with trigonal bipyramidal and octahedral geometries, for instance, we must include d orbitals in the hybridization concept. 

These observations are consistent with a model in which the Pb s and p orbitals hybridize under normal energetic conditions to yield a stereochemically active lone pair and hemidirected structures. [The symmetries of either the nonrelativistic or the relativistic sets of orbitals are consistent with this hybridization (77, 78).] In the holodirected case, on the other hand, no hybridization takes place. The 6s electrons remain in the spherically symmetric s orbital and do not affect the molecular geometry. Holodirected complexes only appear with very large or bulky ligands, in which steric effects outweigh... 

The s and p orbital hybridization schemes are especially important in organic compounds, whose principal elements are C, O, and N, in addition to H. We will consider some important applications to organic chemistry in the next... 

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