dative bonding vs covalent bonding

[JadenErius]

sorry if this is in the wrong section but I thought this section would be best suited to this topic. Anyway back to the topic.

Can anyone tell me the difference between dative and normal covalent bonding? I've read that they is no difference in them once it has been set up. Can anyone tell me why is that so and why does dative bonding occur?

[Greippi]

A dative bond (aka dipolar bond) is where one atom donates both electrons to a bond.

This commonly happens with hydrogen ions - with no electrons. They can accept two electrons to complete their electron shell from e.g. NH3 to form the ammonium ion.

It's no different from a covalent bond as the end result you can't tell where the electrons came from.

[JadenErius]

for example the ammonium ion, how does the positive charge spread across the ion?

[JadenErius]

why isnt anyone replying me? Is it cause no one knows or cause its slightly off topic?

[hermanntrude]

this is a smallish forum, it takes a while to get answers. sometimes u won't get them at all, especially if the question doesn't interest people.

 

In ammonium, the positive charge is considered to be mostly on the nitrogen (it has what we call a formal charge of +1. Formal charges are best learned by reading. try google). Ammonium is entirely symmetrical and none of the bonds is any different to the others, although one is formed by the donation of the lone pair on ammonia to an empty s-orbital in an H+ ion.

 

dative bonds form for the same reason any bond forms: because it can. the positive-negative-positive arrangement of nucleus-electrons-nucleus is quite stable.

[JadenErius]

makes sense, thanks for answering my question =D