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In a session I'm solving, I'm presented with the problem of choosing the most appropriate Lewis structure for $\ce{NH3O}$. The two given structures are the following:

and the other which I couldn't draw has Nitrogen as the central atom, surrounded by the hydrogen and oxygen atoms where each H atom is bonded (by a single covalent bond) with the Nitrogen atom and the oxygen atom is bonded by a dative bond to the nitrogen one (The nitrogen donates both atoms in this case) and has 3 nonbonding pairs around it.

I chose the first as an answer, yet the second seems to be the correct one. Can anyone please explain why?

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up vote 11 down vote accepted

Technically, bot structure of $\ce{H2N-OH}$ and $\ce{H3N\rightarrow O}$ may exists. However, in reality hydrogen atom is rather prone to migration and the second structure is not favorable. So, for compound with composition $\ce{NH3O}$ the correct structure would be $\ce{H2N-OH}$. The structure of second type is stable for compound $\ce{NOF3}$ and may be observed for amine oxides like $\ce{(C2H5)3N\rightarrow O}$ or pyridine-N-oxide.

why $\ce{H2N-OH}$ and not $\ce{H3N\rightarrow O}$ ? One can come with several explanations for that, but I would like to focus on one: charge distribution. In $\ce{H3N\rightarrow O}$ nitrogen has to carry formal positive (and actually very real) charge, while for $\ce{H2N-OH}$ the structure has no formal charges. Still, according to some sources up to 20% of hydroxylamine in water exists as ammonia oxide $\ce{H3N\rightarrow O}$, probably, due to stabilization by hydrogen bonds.

Somewhat similar uncertainty may be found for phosphorous compounds (like hypophosphorous acid) and sulfur compounds (like sulfinic acids)

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So basically the first structure is the most probable one and the teacher is wrong? – Hasan Saad Jan 17 at 11:49
@HasanSaad Pretty much. Point to this article if needed.… – permeakra Jan 17 at 12:00
Thanks, I appreciate it. – Hasan Saad Jan 17 at 12:00

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