Oxidation State of Metal

[005532550]

When a compound has an ion outside of the brackets, how does this affect the oxidation state of the metal within the brackets?

[Kayla Ziebell 1H]

Im pretty sure it gets factored in as the other ones do. In our notes, I have down that the oxidation state for Cobalt in [Co(NH3)5Cl]Cl.2H20 is 2 (Cobalt(II)). When looking at the formula, both he Cl atoms have a charge of -1, therefore the compound has a total charge of -2, and to make it neutral, cobalt will take a +2 charge. Even though Cl is outside the brackets I believe the charge gets accounted for.
I think atoms that are outside the bracket are not accounted for when determining coordination compound but I might be wrong on that

[Rose Arcallana 2B]

No? we know the anion outside of the bracket is an indicator of the overall charge of the coordinate complex.

For example, from the achieve HW, [Co(NH3)4Cl2]Cl, we know the coordinate complex has an overall charge of +1 because a singular Cl, with a charge of -1, is able to bind to it and result in a neutral atom. We can determine Co has a +3 charge from the neutral NH3 and Cl contributing two -2 charges to end with a -1 overall charge.

So a better way to look at it is that the anion outside assist in determining the oxidation state of the metal because if you think about it the anion is an after the fact atom where it simply attaches to the complex. The anion is not "making" the metal to change states for its sake. Hopefully that helps :)

[Qinyan Feng 1H]

Hi

From my understanding, the oxidation state of the metal is somehow decided by other anions and the overall charge of the ion (since metal can have a different oxidation state, it is usually hard to determine directly). Charges of anions or common ligands are fixed, so you can decide the charge of metal by using the overall charge to minus the charge of anions (ligands or other known value).

Hope this helps a little bit.

[Phoebe Ko 3E]

I believe the ion outside of the bracket does contribute to the oxidation state of the metal inside the bracket. In other words, we can determine the oxidation state of the metal through the oxidation states of the anions bonded to the metal, as well as the ions bonded to the compound.

From W9 Achieve HW #6, we were asked to determine the oxidation state of Co in [Co(NH3)5Cl]Cl. Since the chloride ion contributes a -1 charge, the overall charge of the compound within the bracket should be +1. NH3 is neutral and the chloro ligand (Cl-) is -1, so the oxidation state of Co would be +2 in order to account for the overall -2 charges. I hope this was helpful!