How atomic orbitals form other orbitals that are directional by lsp20098

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									               Hybridization
How atomic orbitals form other orbitals that are directional
Hybridization

The shapes of the atomic orbitals are inappropriate
for the formation of bonds within the molecules.
For example, here are the shapes of the s and p
atomic orbitals:



                                              Z

      X


                           Y
  s             px         py            pz
Hybridization

To share electrons, the electron wave needs to be
in the direction of the atom be bonded. The s
orbital is not directional and the p orbitals are
directed along the x, y and z axises, but equally in
both positive and negative directions.

                                                Z

       X


                            Y
  s             px          py            pz
Hybridization

To solve this problem, recall that these are waves.
As such one can recombine them in such a way as
to form new waves that, although look different, are
overall identical. Here are the ways that they are
combined.
    Hybridization

    The first combination is to combine the s orbital with
    one of the p orbitals. These are referred to as sp
    hybrids. There are 2 to start with and 2 resultant.


½            +½                     !

½            –½                     !
    Red here indicates a “trouth” in the wave function
    and Green represents a “peak”.
Hybridization

The first combination is to combine the s orbital with
one of the p orbitals. These are referred to as sp
hybrids. There are 2 to start with and 2 resultant.
The small “trouth” in the hybrids are usually not
shown in the overall picture since they are not
involved in the final bonding. The two together
looks like this:


        X



Along one of the axises.
Hybridization

More complicated is the sp2 hybrid formed from an s
orbital 2 of the p orbitals. There are 3 to starting
orbitals and 3 resulting hybrid orbitals.
    Hybridization

    The sp2 hybrid formations:

½        +½                 !


¼         –¼                +½   !



¼         –¼               –½    !
Hybridization

...or more simply for the sp2 hybrid formations:




      +                     !
Hybridization

The next more complicated combination is the
combination the s orbital with three of the p orbitals.
These are referred to as sp3 hybrids. There are 4 to
start with and 4 resulting orbitals.

These are shown on the next slide.
Hybridization

Combinating 1 s orbital
with 3 p orbitals yield 4 sp3
hybrids.
              X                         Y

                                    X



     +                          !           Z


                    Y      Z                Z
Hybridization

or, showing sp3 hybrid formations altogether:

          X




                                                Z
  +                             !    X


                  Y
                          Z                 Y
    Hybridization

    So far these are the hybrids allowed for the rule of
    8. The geometry of these are:




                                                    Z
X                     X
                                            X


                                                Y




     sp - linear      sp2 - trigonal      sp3 - tetrahedral
Hybridization

There are 2 more hybrids which use the d orbitals.
These hybrids are for those central atoms which
have 10 or 12 electrons about them.
Hybridization

For those central atoms which have 10 electrons
about them, a hybrid is formed from an s, 3 ps and
1 d orbital to for 5 sp3d hybrids.
Hybridization

For those central atoms which have 10 electrons
about them, a hybrid is formed from an s, 3 ps and
1 d orbital to for 5 sp3d hybrids. These look like:



                               Z

           X




                      Y
Hybridization

This is a trigonal bipyramid. One can envision this
as two orbitals on the y-axis, up and down, and
three around the waist at 120E from each other:



          back                  Z

          X                         to the side

forward

                      Y
Hybridization

For those central atoms which have 12 electrons
about them, a hybrid is formed from an s, 3 ps and
2 d orbital to for 6 sp3d2 hybrids.
Hybridization

For those central atoms which have 12 electrons
about them, a hybrid is formed from an s, 3 ps and
2 d orbital to for 6 sp3d2 hybrids. This looks like:



                                Z

            X




                       Y
Hybridization

This is the octahedral arrangement with 2 orbital on
each of the axises in the + and – direction:




                               Z

           X




                      Y
Hybridization

Hybrids are formed from the following atomic
orbitals, yielding the following shapes for the orbitals
formed:

1 s and 1 p - 2 sp hybrids - linear
1 s and 2 ps - 3 sp2 hybrids - trigonal
1 s and 3 ps - 4 sp3 hybrids - tetrahedral
1 s, 3 ps and 1 d - 5 sp3d hybrids - trigonal bipyramid
1 s, 3 ps and 2 ds- 6 sp3d2 hybrids - octahedral
The End of Hybridization

								
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