# What is the first ionization energy of the hydride ion?

What is the first ionization energy for hydride?

Since there are two electrons in the s orbital, I suppose it should be more stable than hydrogen, despite the extra electric charge, so the ionization energy should be greater than the 13 eV needed to ionize hydrogen. However, I could not find any table with the energies for hydride.

## migrated from biology.stackexchange.comFeb 21 at 13:50

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• The negative ion of hydrogen used in biology has no relation whatsoever to the one used in chemistry. – Ivan Neretin Feb 21 at 13:57
• From what I can tell, OP is interested in the chemical species, not the biological equivalents of it. The mention of hydride as a biological reductant was only there to justify their posting on Biology.SE. Since the question has been migrated to Chemistry, I removed that reference. – orthocresol Feb 21 at 14:20
• @orthocresol My impression was exactly opposite. – Ivan Neretin Feb 21 at 14:35
• @orthocresol is right, I am not interested in the biological properties of hydride. I would like to understand whether an ion with 2 electrons in the orbital s is more stable than an atom with 1 electron in the same orbital. From what I have seen, hydride is not very stable since a photon of light can displace the extra electron. This does not happen with hydrogen... – Gigiux Feb 22 at 14:29
• @Gigiux, careful there. A photon can strip a hydrogen atom of an electron. You just need a photon that matches the first ionization energy. – Zhe Feb 22 at 14:51

$$\ce{H + e- -> H-}$$
You'd measure the enthalpy change here as the electron affinity (EA) of the hydrogen atom. The Wikipedia data page says $$72.8\ \mathrm{kJ}/\mathrm{mol}$$.