What is the oxidation state of the metal centre in #[Fe(OH_2)_5(NCS)]SO_4#?

1 Answer
May 1, 2017

We have #"ferric ion"#, i.e. #Fe(+III)#.

Explanation:

We have #[Fe(OH_2)_5(NCS)]^(2+)SO_4^(2-)#.

And the actual complex ion is #[Fe{(OH)_2}_5(NCS)]^(2+)# after we remove the #SO_4^(2-)# counterion. The water ligands are neutral, but the thiocyanate ion has a formal #-1# charge. And thus we have an #Fe^(3+)# centre. Capisce?