Hydride Ion
See also: Hydrogen anionFree hydride anions exist only under extreme conditions and are not invoked for homogeneous solution. Instead, many compounds have hydrogen centres with hydridic character.
Aside from electride, the hydride ion is the simplest possible anion, consisting of two electrons and a proton. Hydrogen has a relatively low electron affinity, 72.77 kJ/mol and reacts exothermically with protons as a powerful Lewis base.
-
- H− + H+ → H2; ΔH = −1676 kJ/mol
The low electron affinity of hydrogen and the strength of the H–H bond (∆HBE = 436 kJ/mol) means that the hydride ion would also be a strong reducing agent
-
- H2 + 2e− ⇌ 2H−; E
o= −2.25 V
- H2 + 2e− ⇌ 2H−; E
Read more about this topic: Hydrides