In my 10th grade book, it says that

A coordinate bond has properties of both covalent and ionic bonds. Therefore, it is also called dative or co-ionic bonds.

I understand that it has properties of covalent bonds, as electrons are still "shared" among the elements(though pair is provided by only one of the atoms), but how does it have ionic properties?


Ionic character means that there is some degree of charge separation, as in standard covalent bonds between atoms of different electronegativity, and even more so due to the mechanism of bond formation.

At an entry level, and I would say even at more advanced level, a formed dative bond is just a covalent bond, albeit a polar - often very polar - one.

You might read this thread If bond types are in reality intermixed, how come different bonds form completely different structures? which in part relates to the use of words like ionic character etc. Those terms are perfectly intelligible once one has a clear idea, but it seems that they have some limitations when a clear idea has to be conveyed to beginners.

You can refer to https://en.m.wikipedia.org/wiki/Coordinate_covalent_bond to see that in special cases and according to some authors the use of the specific term dative as well as its drawing by an arrow should be preferred.

IUPAC does indeed define a dative bond: https://goldbook.iupac.org/terms/view/D01523 Note that even without other considerations, IUPAC gives emphasis to the fact that a dative bond tends to break in a heterolytic way, so ionic character it is at least justified when its splitting is considered.

I would finally add a personal note. An ionic bond is per se quite strong. Increasing polarity of a covalent bond also usually increases the same bond strength. However for a dative bond, according to the IUPAC def. above, peculiarities are a long bond distance and a relative weakness. So again, the reality must be learned first, than some words just help the communication between initiated. As this community shows, no one use pictorial or even obscure terms just for fun or sake of closure.


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