Gaël Labat, Colette Boskovic and Hans U. Güdel
Hexakis(m₄-2-amino-2-methylpropane-1,3-diolato)hexachloroheptairon(II,III) acetonitrile disolvate monohydrate
Acta Cryst. E 61, m611-m613 (2005)                       

Abstract: Single crystals of a new mixed-valence compound, [Fe₇(C₄H₉NO₂)₆Cl₆]·2CH₃CN·H₂O, were synthesized by solvothermal methods. The crystal structure consists of discrete heptanuclear complexes which are linked by weak intermolecular C-H···Cl hydrogen bonds to form a two-dimensional network. In each complex, a central Fe atom is connected to six surrounding Fe centres by alkoxo-type O atoms from the organic ligand. Bond-valence sum calculations indicate that the central Fe ion is Fe^II, as are two of the outer Fe centers, while the remaining four Fe centers are Fe^III. Although the outer Fe atoms are crystallographically equivalent, it is uncertain whether this arises from positional disorder or charge delocalization. The molecular structure has S₆ point symmetry.