Sigma bonds

A sigma (σ) bond is the strongest type of covalent bond formed when two atomic orbitals overlap directly along the axis connecting the two nuclei. This overlap allows the shared electrons to be concentrated in the space between the atoms, creating a strong, stable connection. Sigma bonds are the first bonds formed between two atoms and are fundamental to the structure of molecules. They facilitate free rotation around the bond axis and are essential for the integrity of many chemical compounds, such as hydrocarbons like methane and ethane.