C-C Bond Type in Acetone: Sigma-Bond?

[JonnyG]

I know that in acetone the central carbon atom is $sp^2$ hybridized. It is bonded to the single oxygen atom with a $\sigma$-bond and a $\pi$-bond. But what is the bond type with the two C-C bonds? The lower carbon atoms are $sp^3$ hybridized and so their geometry is tetrahedral. Are the two "lower" carbon atoms oriented such that the C-C bond is a $\sigma$-bond? If so, can we generalize this and say that all single bonds are $\sigma$-bonds?

 

[DrClaude]

On the other carbon atoms, all p orbitals have been hybridized into sp³, so there are no possibilities of making π bonds.

I don't know of a single example of a single bond that is not a σ bond. That may be wrong, but it is at least a very good rule of thumb.

 

[DrDu]

I know that in acetone the central carbon atom is $sp^2$ hybridized. It is bonded to the single oxygen atom with a $\sigma$-bond and a $\pi$-bond. But what is the bond type with the two C-C bonds? The lower carbon atoms are $sp^3$ hybridized and so their geometry is tetrahedral. Are the two "lower" carbon atoms oriented such that the C-C bond is a $\sigma$-bond? If so, can we generalize this and say that all single bonds are $\sigma$-bonds?

How is a sigma bond defined?

 

[olle isaxon]

A sigma bond is defined as a single bond lol. My guess is it's defined according to the same alphabetical principle as the "spdf" of orbitals. That is, sigma, pi, delta, phi. Am I wrong?

 

[DrClaude]

A sigma bond is defined as a single bond lol.

Where did you read that?