Crystal structure of a third polymorph of tris­(acetyl­acetonato-κ(2) O,O′)iron(III)

In the structure of the title complex, [Fe(C(5)H(7)O(2))(3)] or Fe(acac)(3), the asymmetric unit contains one mol­ecule in a general position. The coordination sphere of the Fe(III) 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.