What is the term for diatomic oxygen, a molecule comprised of two atoms of oxygen?

Diatomic oxygen refers specifically to a molecule made up of two oxygen atoms bonded together. This is represented by the chemical formula O2, where the subscript '2' indicates that there are two oxygen atoms in the molecule. Diatomic molecules play a crucial role in various chemical processes, including respiration and combustion.

In this case, the other options represent different molecules. O3 refers to ozone, which consists of three oxygen atoms; H2O is the formula for water, comprising two hydrogen atoms and one oxygen atom; and CO2 represents carbon dioxide, which consists of one carbon atom and two oxygen atoms. Each of these has a distinct chemical composition and properties, making O2 the correct classification for diatomic oxygen.