Oxidation States

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Diego Zavala 2I
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Oxidation States

Postby Diego Zavala 2I » Sun Dec 03, 2017 10:34 pm

How do you determine the oxidation state in a compound with a transition metal?

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Re: Oxidation States

Postby CameronJohari1J » Sun Dec 03, 2017 10:43 pm

Look at the charge of the ligands and then the overall charge of the coordination complex. The sum of the ligand charges plus that of the transition metal equals the overall charge. From this equation solve for the transition metal charge which is the oxidation state.

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Re: Oxidation States

Postby mendozayael_2H » Sun Dec 03, 2017 10:48 pm

To determine the oxidation state of a metal in a complex ion, use this formula: Oxidation # = Charge of ion - [(number (amount) of ligand) X (charge of ligand)]. If you have multiple ligands, do the bracketed values once for each ligand.

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Re: Oxidation States

Postby juchung7 » Sun Dec 03, 2017 10:49 pm

An example: given Pt(NH3)2Cl4 find the oxidation number for Platinum
So we know that NH3 is a neutral ligand, and Cl has a -1 oxidation number. Since there are two 0 charge NH3 and four -1 charge Cl, there is a -4 charge by the ligands. To make this compound have an overall charge of 0, Platinum must have a charge of +4, thus it;s oxidation number is +4.

Julian Krzysiak 2K
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Re: Oxidation States

Postby Julian Krzysiak 2K » Sun Dec 03, 2017 10:54 pm

Are you saying if you want to find the oxidation state for anything, or just the transition metal in the coordination complex?

For many elements, you can find the oxidation state by imagining what would happen if the element were in an ionic bond, and were to have a full octet. How many electrons would it need to lose/gain in order to get to that state? For example, Sodium would have an oxidation state of 1+, since it would need to lose an electron, giving it a positive charge. Fluoride would have an oxidation state of 1-, since it needs to add an electron, a negative charge, to complete the octet.

Now, in order to find oxidation state for transition metals, you need to look at the whole complex'a charge, along with any other ligands that have a charge, and simply subtract/add to find the oxidation number.

For example, [Fe(CN)6]^4- You would need to consider any ligands and if they have a charge. Here, the cyanido ligands have a 1- charge. Since there are 6 of them, that would make the whole complex have a 6- charge, but it has a 4- charge. This means that the Iron has to have an oxidation state of 2+.

E.g. [Co(NH3)6]^3+ The amine groups dont have any charge, meaning that the Cobalt would have an oxidation state of 3+.

Also, writing out the oxidation state normally for transition metals would mean writing it in roman numerals after the metal, i.e., Co (III)

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