Naked Science Forum
Non Life Sciences => Chemistry => Topic started by: johnson039 on 01/01/2009 12:13:45
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stigma bond is the overlapping of s-orbital, pi bond for the p-orbital,
then, is there any bond for d-orbital, or even f-orbital?
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A stigma is a part of a flower, I think you mean sigma...
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But it is an interesting question, most d-block and f-block elements don't usually bond covalenly unless it is to form complex ions. Bonding between the central atom or ion and the ligands is either an ion-dipole bond or a covalent bond formed by a process know as co-ordination (the process in which a covalent bond is formed using a pair of electrons supplied by one atom is referred to as co-ordination). Therefore, there is no head on overlap of orbitals or anything like that, unlike sigma or pi bonds.
All metal atoms are able to form complexes, though many do so only rarely and under particular circumstances. The ones that do so are the transition metals which have unoccupied d-orbitals into which they can accept electron pairs from the ligands.
Is that clear [:P]? I think I might have made a right royal mess of explaining this... [:I]
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A sigma bond can also be formed by the overlapping of hybrid orbitals. The only criterion for a bond to be called a sigma bond is that the region of the orbital overlap is along the line of centres of the two atoms... Forgive the ASCII art.
|===| A pi bond would occur along the "="
| | A sigma bond would occur along the ">>"
-O>>O-
| | So if we use Ethane for example, the C-H bond
|===| is still considered a sigma bond, even though
it is an s-sp3 overlap.
So coordinate bonds in ligands can be considered sigma bonds since the region of overlap is between the lines of centres.
H H Ligand formation is very much similar to the formation of the
\ / complex to the left, consisting of an sp3-sp3 overlap instead.
H-N->B-H
/ \
H H
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A stigma is a part of a flower, I think you mean sigma...
yeah, thx for correcting it ==