The electron presence in anti-bonding orbital result in repulsion and decrease of stability The stability order follows the molecular orbital theory The formula for bonding order can be regarded as follows Bonding order =
1
2
(Number of bonding electrons -Number of antibonding electrons) The number of antibonding electrons in H2+is 0 The number of antibonding electrons in H2−is 1 The bonding order of H2+is =
1
2
(1−0)=0.5 The bonding order of H2−is =
1
2
(2−1)=0.5 H2+and H2−molecule have the same bond order Presence of anti-bonding electron decreases the stability of the molecule Therefore, H2+is more stable than H2−