We have measured the magnetic properties of the cluster compound Ni23Se12(PEt3)13, where PEt3 is triethyl phosphine, by dc magnetization (1.5–300 K) and ac susceptibility (0.280–4 K). We observe a small, almost temperature-independent, magnetic moment of only ~2μB/cluster indicating the presence of two unpaired spins in the cluster. Despite the large shape anisotropy of the molecule, we find no preferred magnetic axis. We interpret this as the result of delocalization of the valence electrons due to covalent Ni-Se bonding.
