ligand induced reductions are not new and have been known to happen with a variety of lanthanide complexes. However, steric factors must also be considered on the reactivity of the Sm(III) complex as less crowded structures do not have any reductive activity. For years, it was thought that (C5Me5)3Sm was not a possible compound due to the huge strain of cone angles greater than 120 degrees. However, this compound is formed from the Sm(II) complex, and X-Ray structures of the Sm(II) complex have shown that there was enough room for a third spot. Also, X-ray structures of (C5Me5)3Sm show that the C5Me5s are 0.1 Angstroms farther from the metal than normally predicted and expected. This increased distance, forced by sterics, makes the ligands have less electronic stability and may be a possible reason for the observed redox reaction of the ligands instead of the metal. Sm is a typical and well studied metal due to its unusual stability in a divalent and trivalent state. With the discovery of sterically induced reductions other lanthanide metals can now be studied in their more stable trivalent state, which can allow for more control of reduction reactions by tuning the reaction based on the metal size and electronics. References Coordination chemistry