Number of electron does species have
The H22- ion can be conceived to result from the combination of two hydride ions (H-). This species have four electrons; two occupy the bonding molecular orbital, and two occupy the antibonding molecular orbital. In this species, the energetic benefit of the electrons in the bonding molecular orbital is cancelled by the energetic disadvantage of the similar number of electrons in the antibonding molecular orbital. This species consequently has no energetic benefit over two dissociated hydride (H-) ions, and thus it readily dissociates.