N2O4, also known as dinitrogen tetroxide, is a covalent compound. This classification arises from the nature of the bond formed between the nitrogen and oxygen atoms in the molecule.
Covalent bonds occur when two atoms share electrons in order to achieve a more stable electronic configuration. In the case of N2O4, nitrogen (N) atoms and oxygen (O) atoms share electrons to fulfill the octet rule, which provides each atom with eight electrons in its outer shell. Specifically, in N2O4, each nitrogen atom forms two covalent bonds with an oxygen atom, resulting in a stable molecular structure.
On the other hand, ionic compounds are formed when there is a complete transfer of electrons from one atom to another, usually between metals and nonmetals. In ionic bonding, this transfer creates charged ions which are held together by electrostatic forces. Since N2O4 does not involve the transfer of electrons and no charged ions are present, it cannot be classified as ionic.
In conclusion, due to the sharing of electrons between the nitrogen and oxygen atoms, N2O4 is identified as a covalent compound.