A stable and strongly ferromagnetic Fe(17)O(10)(–) cluster with an accordion-like structure

Isolated clusters are ideal systems for tailoring molecule-based magnets and investigating the evolution of magnetic order from microscopic to macroscopic regime. We have prepared pure Fe(n)(–) (n = 7-31) clusters and observed their gas-collisional reactions with oxygen in a flow tube reactor. Interestingly, only the larger Fe(n)(–) (n ≥ 15) clusters support the observation of O(2)-intake, while the smaller clusters Fe(n)(–) (n = 7-14) are nearly nonreactive. What is more interesting is that Fe(17)O(10)(–) shows up with prominent abundance in the mass spectra indicative of its distinct inertness. In combination with DFT calculations, we unveil the stability of Fe(17)O(10)(–) within an interesting acordion-like structure and elucidate the spin accommodation in such a strongly ferromagnetic iron cluster oxide.