COMPOUNDS WITH INTERMEDIATE SPIN .2. CRYSTAL-STRUCTURE OF TRIS(1,10-PHENANTHROLINE)IRON(II) IODIDE DIHYDRATE

The crystal structure of tris(1,10-phenthroline)iron(II) iodide dihydrate, Fe(C12N2H8)3I2 ·2H2O, has been determined from X-ray intensity data collected on a four circle diffractometer. The space group is P21/a with four formula units in the cell. The cell dimensions are a = 10.623(2), b = 16.402(2), c = 20.375(4) Å, and β = 104.48(1)°. The structure was refined by least-squares methods to a conventional R factor of 7.2%. Each Fe is pseudo-octahedrally coordinated by three phenanthroline molecules with FeN distances in the range 1.96-1.99 Å. The coordination polyhedra are packed in layers parallel to the ab-plane with Fe close to z = 0.25 and 0.75. The water molecules and the iodide ions form hydrogen bond chains between the layers of the metal complexes. The FeO distances are in the range 4.90-5.54 Å, and the FeI distances 6.06-6.43 Å. © 1978.