Crystal structure of a third polymorph of tris(acetylacetonato-κ2 O,O')iron(III)

Abstract

In the structure of the title complex, [Fe(C5H7O2)3] or Fe(acac)3, the asymmetric unit contains one molecule in a general position. The coordination sphere of the FeIII atom is that of a slightly distorted octahedron. The crystal under investigation was a two-component pseudo-merohedral twin in the monoclinic system with a β angle close to 90°. Twin law [100/0-10/00-1] reduced the R1 residual [I > 2σ(I)] from 0.0769 to 0.0312, and the mass ratio of twin components refined to 0.8913(5):0.1087(5). In the crystal, molecules are arranged in sheets normal to [001] via non-classical C - H⋯O hydrogen bonding. No other significant intermolecular interactions are observed. The structure is a new polymorph of Fe(acac)3 and is isotypic with one polymorph of its gallium analog.