# 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."?

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.

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

Here are some examples of σ bonds,

Hydrogen has an $\text{s-s}$ σ bond, hydrogen fluoride has an $\text{s-p}$ σ bond, and fluorine has a $\text{p-p}$ σ bond.

Ethane has an $\text{sp"^3"-sp"^3color(white)(l) "C-C}$ σ bond and $\text{sp"^3"-s C-H}$ σ bonds.
You can also have $\text{p-d}$ and $\text{d-d}$ σ bonds.