Electronic structure of paramagnetic clusters of transition metal ions. 3. Magnetic properties and scattered wave description of the electronic structure of the hexanuclear octahedral cluster [Fe₆(μ₃−S)₈(PEt₃)₆] (BPh₄)₂

Spin‐polarized Xα–SW calculations of [Fe 6 (μ 3 −S) 8 (PH 3 ) 6 ] 2+ as a model of the cluster [Fe 6 (μ 3 −S) 8 (PEt 3 ) 6 ] (BPh 4 ) 2 have been performed. The highest occupied energy levels are well separated from empty levels, and up to a maximum of eight electrons can be unpaired, giving a maximum spin state with S = 4. This electronic state is consistent with the magnetic data of [Fe 6 (μ 3 −S) 8 (PEt 3 ) 6 ](BPh 4 ) 2 , which have been interpreted using the Heisenberg–Dirac–Van Vleck exchange spin Hamiltonian. The S = 4 state arises from the magnetic coupling between five low‐spin ( S i = 1/2) and one intermediate‐spin ( S = 3/2) iron(III) center.