How many unpaired electrons does Fe(acac)3 have?

To determine the number of unpaired electrons in Fe(acac)3, we need to know the electron configuration of Fe and the nature of the ligand acac.

1. Iron (Fe) in its ground state has the electron configuration [Ar] 3d6 4s2.

2. In Fe(acac)3, Fe is in its +3 oxidation state (Fe3+), which means it has lost 3 electrons. Two of these electrons are removed from the 4s orbital and one from the 3d orbital, leaving us with the electron configuration [Ar] 3d5.

3. The ligand acac is a weak field ligand, which means it does not cause a large split in the d orbitals. Therefore, the five d electrons will fill up the five d orbitals singly first before any pairing occurs (according to Hund's rule).

4. Therefore, Fe(acac)3 has 5 unpaired electrons.