Single-molecule magnets are also based on iron clusters because they potentially have large spin states. In addition, the biomolecule ferritin is also considered a nanomagnet. In the cluster Fe 8 Br the cation Fe 8 stands for [Fe 8 O 2 (OH) 12 (tacn) 6 ], with tacn representing 1,4,7-triazacyclononane.