Is the Fe(C2O4)33- ion an inner or outer orbital complex?

http://en.wikipedia.org/wiki/Potassium_ferrioxalate

See the site above. This is a high spin complex which I believe means it is an outer orbital complex.

To determine whether the Fe(C2O4)33- ion is an inner or outer orbital complex, we need to consider the electronic configuration and the ligand field splitting.

First, let's determine the electronic configuration of Fe(III) ion (Fe3+). Fe has an atomic number of 26, and with a charge of +3, it loses 3 electrons to form Fe3+. Hence, the electronic configuration of Fe3+ is: 1s2 2s2 2p6 3s2 3p6 3d5.

Now, let's examine the ligand in Fe(C2O4)33-. C2O4 represents the oxalate ion, which is a bidentate ligand. This means that each oxalate ligand can coordinate with Fe3+ through two donor atoms.

Since there are three C2O4 ligands in Fe(C2O4)33-, we have a total of six donor atoms in coordination with Fe3+. This implies that there are six ligand-metal interactions, leading to the splitting of d orbitals.

The ligand field splitting in Fe(C2O4)33- is quite large compared to the pairing energy, causing the electrons to get distributed across both the lower and upper energy levels of the d orbitals. As a result, the Fe(C2O4)33- ion is classified as an outer orbital complex.

To summarize, Fe(C2O4)33- is an outer orbital complex due to the large ligand field splitting and the distribution of electrons between lower and upper energy levels of the d orbitals in the Fe3+ ion.