Hypervalent Oxygen: Violating Rules & Reactions

[caters]

I know that it is possible for 2 H₂O molecules to gain and lose electrons. This reaction looks like this:

2 H₂O -> H₂O⁺ + H₂O^-

This causes 1 of the oxygen atoms to be hypervalent since it now has 9 electrons. The other oxygen has only 7 electrons. The electron on the hypervalent oxygen came from 1 of the other oxygen's lone pairs.

Obviously this ionic water is not stable.

But how is this ionic water possible when it violates 1 of the general rules in chemistry which is that hypervalency starts in the 3rd period not group 16 of the 2nd period.

 

[Abhirikshma]

Is this really true ? Because I have never seen anything like this, rather i have seen this
2H₂O = H₃O⁺ + OH^-
Pls. Read the equal to as a reversible arrow.

 

[caters]

Yes under certain conditions H₂O⁺ and H₂O^- can form

 

[DrDu]

Hypervalency not being possible in 2nd row elements is nowadays known to be a fairy tale, which nevertheless is going on to get told to high school students.
Nevertheless, I don't think that this reaction happens. In gas phase, H2O- is only marginally stable. The electron is bound by the dipole moment of the water molecule and is spread out over a large area. It does not resemble a valence electron at all. On the other hand, it cost's a lot of energy to ionize H2O to H2O+, so this reaction is not feasible in the gas phase.
In solution, H2O- doesn't exist. Rather, there exist a solvated electron for a short time, which rapidly reacts under the formation of H2 and OH-. Again, energetics isn't favourable.