Why can h20 only donate 1 lone pair?

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Katherine Fitzgerald 1A
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Joined: Fri Sep 29, 2017 7:05 am

Why can h20 only donate 1 lone pair?

Postby Katherine Fitzgerald 1A » Wed Jul 24, 2019 8:43 pm

If the oxygen on H2O has 2 lone pairs, why can it only donate one? Similarly, why is it that the oxygens in C2O2 can only donate 1 lone pair? Why can the oxygen with the double bond in C2O2 not donate any at all?

D-nice1D
Posts: 19
Joined: Fri Sep 28, 2018 12:21 am

Re: Why can h20 only donate 1 lone pair?

Postby D-nice1D » Wed Jul 24, 2019 8:51 pm

I think that would lead to the oxygen having a 2+ formal charge

Chris Charton 1F
Posts: 19
Joined: Mon Jun 17, 2019 7:23 am

Re: Why can h20 only donate 1 lone pair?

Postby Chris Charton 1F » Mon Jul 29, 2019 12:25 am

In my understanding with coordinate covalent bonding the element can only donate one pair to another element, no matter how many lone pairs it may have.

David Zhang 1B
Posts: 48
Joined: Mon Jun 17, 2019 7:23 am

Re: Why can h20 only donate 1 lone pair?

Postby David Zhang 1B » Mon Jul 29, 2019 11:05 am

I think the shape of the molecule also plays a role since the way the electron pairs are positioned doesn’t really allow it to form 2 bonds.

Chem_Mod
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Re: Why can h20 only donate 1 lone pair?

Postby Chem_Mod » Mon Jul 29, 2019 4:32 pm

Both answers are correct; water typically donates only 1 lone pair because donating both would give it a very positive formal charge which is highly unfavorable for such an electronegative atom, and because the positioning of the lone pairs prevents both from donating to the same molecule at the same time.


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