An iron(II) complex with a five-coordinate trigonal bipyramical coordination geometry was recently synthesized by University of Washington researchers (Shoner, S. C., Nienstedt, A. M., Ellison, J. J., Kung, I. Y., Barnhart, D., Kovacs, J. A., "Structural Comparison of Five-Coordinate Thiolate-Ligated MII = FeII, CoII, NiII, and ZnII Ions Wrapped in a Chiral Helical Ligand", Inorganic Chemistry; 1998; 37; 5721-5726.). The compound was made in an attempt to model the spectroscopic and reactivity properties of an iron-containing enzyme called nitrile hydratase.

Using the software (which you will need to download) Chime (or RASMOL), you can view and rotate the following images:

• crystal structure of the molecule, as shown above
• molecules packed together in the crystal. (shows about 50 molecules as they pack together)