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### Drawing the Lewis structure for Coordination Compounds

Posted: Wed Dec 06, 2017 10:14 am
If we are given a coordination compound, i.e. [HgF2(OH2))2]1+, do we use the total charge of the compound (1+) to find the formal charge of the lewis structure in addition to finding the oxidation state of the metal atom?

### Re: Drawing the Lewis structure for Coordination Compounds

Posted: Wed Dec 06, 2017 10:16 am
Yes, the formal charges actually refer to the individual atoms and their electrons though, so you would use this number to find the overall charge on the molecule given the individual formal charges.

### Re: Drawing the Lewis structure for Coordination Compounds

Posted: Wed Dec 06, 2017 10:19 am
In short: yes, I think so. The charge on the outside lets you know the overall charge of the whole molecule, thus it should be kept into account when drawing a Lewis structure. For your example for instance, [HgF2(OH2))2]1+, I believe the oxidation number of Hg would be (V) since there are 4 negative charges (2 from F- and 2 from OH-) but an overall +1 charge on the molecule.

### Re: Drawing the Lewis structure for Coordination Compounds

Posted: Wed Dec 06, 2017 10:35 am
Austin Ho 1E wrote:In short: yes, I think so. The charge on the outside lets you know the overall charge of the whole molecule, thus it should be kept into account when drawing a Lewis structure. For your example for instance, [HgF2(OH2))2]1+, I believe the oxidation number of Hg would be (V) since there are 4 negative charges (2 from F- and 2 from OH-) but an overall +1 charge on the molecule.

The OH2 is neutral; therefore it doesn't have a charge. There would be a -2 charge from F2; therefore, the oxidation number of mercury would be (III).