* Diatomic Oxygen (O₂): This is the most common form of oxygen found in the air we breathe. It is a colorless, odorless, and tasteless gas.

* Ozone (O₃): Ozone is a triatomic molecule, meaning it contains three oxygen atoms. It is a pale blue gas with a pungent odor and is a powerful oxidizer.

There are also other, less common forms of oxygen, including:

* Atomic Oxygen (O): This is a highly reactive and short-lived form of oxygen that is found in the upper atmosphere.

* Oxygen Ions (O⁻, O²⁻): These are negatively charged oxygen atoms that are found in various chemical compounds.

In summary, the most common chemical form of oxygen is diatomic oxygen (O₂).