Modern computational chemistry demonstrates that bonds traditionally classified as ionic frequently possess partial covalent character, involving overlapping atomic orbitals that form bonding and antibonding molecular orbitals.
Although ionic bonding is classically viewed purely through electrostatic attraction, advanced quantum chemical studies (such as DFT and NBO analyses) regularly evaluate ionic bonds for covalent contributions, revealing that molecular orbital descriptions incorporating bonding and anti-bonding orbitals apply across various systems traditionally termed ionic.