When an oxygen atom forms chemical bonds with other atoms, it shares its orbitals through a process called orbital overlap. In particular, oxygen commonly forms covalent bonds, where it shares electrons with other atoms.
Oxygen has six valence electrons, occupying two 2s orbitals and two 2p orbitals. In the process of bonding, these valence electrons can participate in the formation of new molecular orbitals by overlapping with the orbitals of other atoms.
Let's take the example of oxygen forming a covalent bond with another oxygen atom to create an oxygen molecule (O2). Each oxygen atom has two unpaired electrons in its 2p orbitals. In the bonding process, one electron from each oxygen atom is shared, resulting in the formation of a sigma (σ) bond.
The overlapping of atomic orbitals occurs as follows:
The 2p orbitals of the oxygen atoms approach each other. They align in a head-to-head fashion along the internuclear axis, forming a molecular orbital known as a sigma bonding orbital (σ bond).
The overlap occurs between the lobes of the 2p orbitals, enabling the shared electron density to be concentrated along the internuclear axis. This overlapping region is where the electrons are most likely to be found.
As a result, the shared electrons occupy the newly formed molecular orbital, which encompasses the entire molecule rather than being localized to a specific atom.
This process of orbital overlap and electron sharing allows oxygen atoms to achieve a more stable electron configuration, satisfying the octet rule (having eight electrons in the valence shell) and lowering their overall energy.
It's important to note that oxygen can also form other types of bonds, such as double or triple bonds, depending on the number of electrons it shares with other atoms. In these cases, additional p orbitals may participate in the overlap, resulting in the formation of pi (π) bonds alongside the sigma bond.
Overall, the sharing of orbitals between oxygen and other atoms facilitates the formation of chemical bonds and the creation of stable molecules.