The reason why OF2 is not considered an oxide is due to the difference in electronegativity between oxygen and fluorine. Electronegativity is a measure of an atom’s ability to attract electrons towards itself in a chemical bond. Fluorine has a higher electronegativity than oxygen, which means it has a stronger pull on the shared electrons in a bond.
When oxygen forms a compound with fluorine, such as OF2, the fluorine atom attracts the shared electrons more strongly than the oxygen atom. This creates a polar covalent bond, where the electrons are unequally shared between the two atoms. In OF2, the oxygen atom has a partial positive charge (+δ) and the fluorine atoms have partial negative charges (-δ).
In contrast, when oxygen forms compounds with elements that have lower electronegativity, such as metals or nonmetals with lower electronegativity than oxygen, the resulting compound is typically considered an oxide. In oxides, the oxygen atom has a negative charge and the other element has a positive charge.
To further clarify, let’s compare OF2 with a well-known oxide, such as CO2 (carbon dioxide). In CO2, carbon and oxygen have a significant difference in electronegativity, but it is not as pronounced as the difference between oxygen and fluorine. The electronegativity difference in CO2 results in a polar covalent bond, but the oxygen atom still has a partial negative charge, while the carbon atom has a partial positive charge. This gives CO2 its oxide characteristic.
The reason why OF2 is not considered an oxide is because the electronegativity of fluorine is greater than that of oxygen, leading to a stronger pull on the shared electrons and a different distribution of charges within the molecule.