Can a #"C"-"C"# bond exist in a stable compound?

1 Answer
Truong-Son N.
Oct 11, 2017

Yes it can... nearly every hydrocarbon proves that.

In any hydrocarbon containing two or more carbons, one must have a carbon-carbon bond.

#"H"_3"C"-"CH"_3#

#"H"_3"C"-"CH"_2-"CH"_3#

etc.

In all of these, carbon bonds with itself, and forms a stable compound.

Carbon cannot, however, form a stable #"C"_2# molecule at room temperature.

https://qph.ec.quoracdn.net/

Here, the MO diagram of #"C"_2# suggests a Lewis structure of:

#:stackrel(..)"C"=stackrel(..)"C":#

The formal charge on each carbon is #-2# and not #0# like it would be for a nonpolar homonuclear diatomic molecule.

Its #pi# electrons are also in separate orbitals, so the #pi# bond I drew is really artificial. In reality the #"C"_2# compound would then have two half-#pi#-bonds using perpendicular sets of orbitals, so it's not quite a regular double bond overall...

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