Part 1: I was just reviewing concept of the dative covalent bond in some simple molecules. One of which was carbon monoxide.

Some structures I saw featured the use of formal charges, in which the carbon atom had a negative formal charge while the oxygen atom had positive formal charge. These did not show that a dative bond was involved.

Some I saw claimed the molecule remained neutral and showed a dative bond between the two atoms.

I understand that the formal charge is a theoretical construct and does not refer to actual charges on atoms. Rather, they indicate to the chemists where are the regions of electron-richness and electron-deficiency.

So these two structures do not contradict each other and each are limited in some way.

However, dative bonding in complex metal ions always show dative bonding which is the latter structure, never the former structure, with formal charges. Why is this so?

Part 2: Secondly, what are the differences between a dative covalent bond, where one species donating both electrons, and a typical covalent bond, where each species donates one electron. Other than the process of bond making, is every other characteristic of the two bonds the same?

If you think about it, a lot of covalent bonds are actually "dative". Consider all the bonds between nucleophiles and electrophiles. Isn't it always the case where the nucleophile donates a pair of electrons?

In my opinion, the only difference appears to only be the difference in the bond making process and all else is exactly the same.

  • $\begingroup$ Possible duplicate of The bond in coordination complexes $\endgroup$
    – Mithoron
    Commented Jun 17, 2017 at 14:08
  • $\begingroup$ Second part may be a dupe of chemistry.stackexchange.com/questions/39293/… $\endgroup$
    – Mithoron
    Commented Jun 17, 2017 at 14:10
  • $\begingroup$ I agree with Mith. This is a dupe of two different questions. Since it is also to not-so-related questions in one, I’m going to vote to close it as too broad. $\endgroup$
    – Jan
    Commented Jun 17, 2017 at 14:25
  • $\begingroup$ @Mithoron I agree that my question is a duplicate, sorry for the mistake on my part as I did not see those posts when I searched the site. However, I would like to point out the accepted answers to the two questions on those two posts are somewhat lacking and do not give complete and coherent responses to my questions. $\endgroup$ Commented Jun 17, 2017 at 17:49
  • $\begingroup$ Philipp has just recently revealed in his reply to my comment claiming that based on his knowledge of MO, there is not much of a difference between the coordinate covalent bonds and non-coordinate covalent bonds. Jan has also clarified in his replies to my comments that the difference lies in whether the bond cleaves homo- or hetero- lytically upon addition of bond dissociation energy. Both answers are not substantiated by any sources regarding the views they hold and I find Jan's answer very dubious, based on my knowledge of chemistry. $\endgroup$ Commented Jun 17, 2017 at 17:55