General Question on Coordinate Covalent Bonds

[Alexa Pham 1D]

How do we know when two atoms have a coordinate covalent bond and when two atoms don't? For example, if we were to draw a Lewis structure on some molecule that has coordinate covalent bonds, how would we know that there are those coordinate covalent bonds in the molecule?

[Arielle Sass 2A]

Hi!
I don’t think there’s an exact way to know if a bond is a coordinate covalent bond just from looking at it, but I can imagine that if you have a good idea of some common Lewis acids and bases (H+, NH3, etc) you might be able to know that a molecule was a result of these other molecules bonding. For our class though, I’m pretty sure that we’ll only have to know how to recognize a coordinate covalent bond from two atoms/molecules when they’re still separate.

[AnnaNovoselov1G]

I think a coordinate covalent bond is when one atom donates both electrons (for instance in the bond between BF3 and NH3, the the two electrons in the bond both come from NH3. On the other hand, in the bond between two oxygen atoms, the oxygen atoms contribute 1 electron each (regular covalent bond).

[Saumya Tawakley 1E]

To tell if a coordinate covalent bond is present, check to see whether the two shared electrons are coming from the same atom. In the BF4 example, both the shared electrons came from the F- that was added to BF3. Any time one atom is providing both of the shared electrons, it is a coordinate covalent bond.

[chinmayeec 2H]

Dr. Lavelle mentioned in his lecture that there are no differences between a coordinate covalent bond and a normal covalent bond in a molecule like BF4 so I don't think you would be able to tell from the Lewis structures alone. I think you would need to know the molecules that reacted to form a molecule with a coordinate covalent bond: any reaction that involves a Lewis base reacting with a Lewis acid will have a coordinate covalent bond because the Lewis base will provide an electron pair and the Lewis acid will accept it.

Hope this helps!

[Thomas Gimeno]

I think about it like this, I draw each atom and the number of valance electrons it "should" have (so for nitrogen there would be 5). Then I started pairing up the electrons from different atoms to form bonds. If I find that all the valance electrons have been used up and the only way to form the necessary bond is with two electrons from a different atom then I know it's coordinate. This is obviously sorta a long process so I think it's only necessary if the question specifically asks about it. If you want a short cut I woul just memorize the ones he showed in class.

[Xavier Herrera 3H]

A coordinate covalent bond happens when a lewis acid donates both electrons from a lone pair to a lewis base, which needs two electrons to fill its octet. So, in the case of BF3 and NH3, you know there is a coordinate covalent bond because the B only has 6 electrons, so it needs the lone pair from NH3 to fill its octet.

[Bella Bursulaya 3G]

If both of the electrons that fulfilled the octet from the base come from the same element, it will be a coordinate covalent bond. Like in NH3 and BF3. Both electrons to fulfill the octet for B come from N, so it will be a coordinate covalent bond.

[Jaden Haskins 2E]

Are Lewis acids and Lewis bases the only ones involved in coordinate covalent bonding, or is it any transition metal and ligand?