Meaning- "Sigma bonds can occur between any kind of atomic orbitals; the only requirement is that the atomic orbital overlap happens directly between the nuclei of atoms."?

1 Answer
Jun 12, 2017

It is saying that the bonding electrons must be directly between the nuclei of the bonding atoms.

Explanation:

Sigma (σ) bonds are formed by head-on overlapping of atomic orbitals.

upload.wikimedia.org

This puts most of the electron density along the internuclear axis between the two nuclei.

Here are some examples of σ bonds,

leaving-cert-notes.weebly.com

Hydrogen has an #"s-s"# σ bond, hydrogen fluoride has an #"s-p"# σ bond, and fluorine has a #"p-p"# σ bond.

Ethane
(From Google Sites)

Ethane has an #"sp"^3"-sp"^3color(white)(l) "C-C"# σ bond and #"sp"^3"-s C-H"# σ bonds.

You can also have #"p-d"# and #"d-d"# σ bonds.

d sigma
(Adapted from Boundless)

In all of these σ bonds, the bonding electrons are on the internuclear axis between the two nuclei.