* Nature of the Elements: Both nitrogen (N) and oxygen (O) are nonmetals. Nonmetals tend to form covalent bonds by sharing electrons rather than transferring them like in ionic bonds.

* Electronegativity Difference: The electronegativity difference between nitrogen and oxygen is not large enough to form a purely ionic bond. While oxygen is more electronegative than nitrogen, the difference is not significant enough to fully transfer electrons.

* Molecular Structure: N₂O₃ exists as a molecule with a specific arrangement of atoms, indicating covalent bonding.

In summary, N₂O₃ forms covalent bonds due to the sharing of electrons between nitrogen and oxygen atoms within the molecule.