hybridization of the central atom ...what's all that about?

Question

Hands up, I haven't got a clue what its on about, let alone how to work it out.... so for the benefit of others like me, can someone please enlighten?

I've noticed quite a few such questions on site regarding calclulating hybridization....with little response, so I'm not the only one in the dark about molecular chemistry.... so can you please answer as detailed as possible for future searches....Thanks (on behalf of many)

Is this sort of question based solely on inert gasses? most answers are given as sp..this n that...why? what is "sp"?

Listen guys, thanks for all the mind numbing explanations.. the chemistry I believe in may be just as explosive at times but I think I understand that a whole lot better..(I only said ..THINK)... can anyone be mobre basic, layman .. from the top?

now look what you made me do, I can't even spell..lol)

Answer 1

In order to predict the hybridization of the central atom using the molecular profiles of the VSEPR Approach, one has to deal with the electron pair geometry. This will be different then the molecular geometry. Molecular geometry considers the shape with the atoms being considered alone. Electron pair geometry considers any non-bonding electron pairs as groups as well in determing the electron pair geometry. For example, AB4 profile would be tetrahedral molecular geometry. Since there are no non-bonding pairs on the central atom, the electron pair geometry would be the same. In fact all molecular profiles in which there are zero non-bonding (or lone) pairs on the central atom would have the same geometry for molecular geometry and non-bonding pair geometry.


AB6 = octahedral = molecular geometry = non-bonding electron pair geometry = sp3d2 hybridization of central atom
AB5 = Trigonal Bipyramidal = molecular geometry = non-bonding electron pair geometry = sp3d hybridization on the central atom
AB4 = Tetrahedral = molecular geometry = non-bonding electron geometry = sp3 hybridization on central atom
AB3 = Trigonal Planar = molecular geometry = non-bonding electron pair geometry = sp2 hybridization of the central atom
AB2 = linear = molecular geometry = non-bonding electron pair geometry = SP hybridization on the central atom

For molecular profiles where there is one or more non-bonding electron pairs attached to the central atom the non-bonding electron pair geometry which decides the hybridization of the central atom will differ from the molecular geometry where non-bonding electron pairs are not counted.


:AB2 = non-bonding electron pair geometry = trigonal planar = sp2 hybridization on the central atom
:AB3 = ::AB2 = non-bonding electron pair geometry = tetrahedral = sp3 hybridization of central atom
:AB4 = ::AB3 = :::AB2= non-bonding electron pair geometry = Trigonal Bipyramidal = sp3d hybridization of the central atom
:AB5 = ::AB4 = non-bonding electron pair geometry = octahedral = sp3d2 hybridization of central atom
In summary:

It is the number of electron pairs (bonding or non-bonding) connected to the central atom that determines its hybridization. If there are 6 electron pairs then the central atom will be sp3d2. If there are 5 electrons pairs attached to the central atom then the central atom will be sp3d. If there are four electron pairs attached to the central atom then the central atom will be sp3 hybridized. If there are three electron pairs attached to the central atom then the central atom will be sp2 hybridized. If there are two electron pairs attached to the central atom then the central atom will be sp hybridized.

Answer 2

The simple explanation: Hybridization is a tool for approximating the molecular orbitals centered on a central atom, given the number of atoms and lone pairs around that atom. Suppose you have a carbon atom. If the number of things around it is 2, you have sp hybridization (the s orbital and the pz orbital combine in + and - ways to generate orbitals pointing in the direction of the two things). For 3, it would be sp^2, for 4 it would be sp^3. This is a simple picture.

The more general answer:
Molecular orbitals must transform according to the irreducible representations within the symmetry group of the molecule. Using group theory, you can derive the approximate shapes of molecular orbitals centered on a central atom by observing how these orbitals transform under different symmetry operations. The results are often called "hybrid orbitals". These orbitals will allow you to approximate bond angles.

Answer 3

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RE:
hybridization of the central atom ...what's all that about?
Hands up, I haven't got a clue what its on about, let alone how to work it out.... so for the benefit of others like me, can someone please enlighten?

I've noticed quite a few such questions on site regarding calclulating hybridization....with little response, so I'm not the only one...

Answer 4

In valence bond theory, s, p, d, and f orbitals do not bond with other atoms in some kind of free-for-all. Rather they combine with one another to form new orbitals, all of the same kind. These new orbitals then form the bonds. Hybridization is most important in beginning chemistry to understand geometries and bond angles of compounds.

For example, in organic chemistry, sp3 orbitals are directed toward vertexes of an imaginary tetrahedron, with bond angles of 107deg. sp2 leads to planar molecules with bond angles of 120deg. sp give linear molecules, bond angle 180deg.

dsp2 is used by some metals to give square-planar molecules. d2sp3 is used by other metals to give octahedral geometry with bond angles of 90deg (180deg, if you count the ones that are "across" from one another.

For the most part, beginners must learn each case.