I am getting confused with oxidation states of my compounds can someone help me with the oxidation states of the cobalt metal.
[Co(NH3)5Cl]CL2
[Co(NH3)4Cl2)]CL
[Co(acac)2]
[Co(NH3)CO3]NO3-
Also the overall charge of the complex. Thank you
Work out the overall charge of the complex by comparing with the charge on the counter ions.
For example, in [Co(NH3)5Cl]CL2, we know that Cl has a -1 charge, and there are two of them, so to make the compound neutral the charge on the complex part must be 2+.
Now, to work out the oxidation state of the cobalt you need to think about the charge on each of the ligands and also the overall charge of the complex.
So we know the complex is [Co(NH3)5Cl]](2+). We know that NH3 is neutral and Cl is -1. So the contribution to the charge from the ligands is -1 overall. So to get the complex to have an overall +2 charge this means that the cobalt contributes +3, which is its oxidation state.
You can use this expression : metal ox state = Overall complex charge - combined charge contribution from ligands, or just reason it out as above.
Work out the overall charge of the complex by comparing with the charge on the counter ions.
For example, in [Co(NH3)5Cl]CL2, we know that Cl has a -1 charge, and there are two of them, so to make the compound neutral the charge on the complex part must be 2+.
Now, to work out the oxidation state of the cobalt you need to think about the charge on each of the ligands and also the overall charge of the complex.
So we know the complex is [Co(NH3)5Cl]](2+). We know that NH3 is neutral and Cl is -1. So the contribution to the charge from the ligands is -1 overall. So to get the complex to have an overall +2 charge this means that the cobalt contributes +3, which is its oxidation state.
You can use this expression : metal ox state = Overall complex charge - combined charge contribution from ligands, or just reason it out as above.
FYI, acac and CO are neutral.
For [Co(NH3)5Cl]Cl2 oxidation state Cl = -1, NH3 = 0 therefore Co = 2+
overally charge I got is 2+
for [Co(NH3)4Cl2]Cl
oxidation states Cl = -2 NH3 = 0 therefore Co = 1+
overall charge = ?
for [Co(acac)2] oxidation state acac= 0 or is it -2 as 2 oxgyens are coordinated to the cobalt, colbalt = 1+ or 3+
for Co(NH3)CO3 Oxidation state NH3 = 0 CO3 = Is it -2 since 2 oxygen is coordinated to the cobalt? Overall charge ??
therefor Co oxidation is +3 and charge is +1 for [Co(NH3)4Cl2]Cl
so for [CO(NH3)5Cl] Co oxidation is =
[Co(NH3)5Cl2]Cl, Cl is -2 and counterion outside the bracket is -1 therefore oxidation of Co + (-2) = -1 Co= (2+1) Co=+3
charge = +2
I think you confused the formula a bit there ... there are 2 chlorines outside the complex in your question, and only one inside.
If we were to follow this one through though: [Co(NH3)5Cl2]Cl, then the charge on the complex would be +1, because it has to neutralise the -1 Cl on the outside of it.
The ligands would be indeed have a -2 charge, so to get the overall charge to be +1 the cobalt does need to contribute +3.
Sunnydazzleeyes
is the above correct?
Also what is the overall charge of acac? Is it -2 as two oxgyen is attatched to Co. acac2-?
And the oxidation state of CO3 where 2 oxygen binds to the Co metal. CO3?
I think you confused the formula a bit there ... there are 2 chlorines outside the complex in your question, and only one inside.
If we were to follow this one through though: [Co(NH3)5Cl2]Cl, then the charge on the complex would be +1, because it has to neutralise the -1 Cl on the outside of it.
The ligands would be indeed have a -2 charge, so to get the overall charge to be +1 the cobalt does need to contribute +3.