Chemists have discovered a new, highly reactive form of iron that promises to deepen our understanding of this important element. Iron is found in abundance in the natural world, and in its ionized form plays a crucial role in virtually all living processes.

Iron can have as many as eight electrons in its outer shell, but most typically iron has five or six of these valence electrons. The new form of iron, designated iron VI, has only two electrons in its outer shell, making it very electron deficient and thus highly reactive. Only one other form of iron VI, called ferrate, is known. Ferrate is a powerful oxidant, but reacts indiscriminately and thus can be difficult to use. The new species of iron VI instead forms a bond with nitrogen, which could result in different reactivity, which has promise for industrial and biomedical applications.

"We hope that this complex will have practical advantages over other iron compounds, and we might expect that it does based on its structure," explained John F. Berry, an Alexander von Humboldt postdoctoral fellow at Germany's Max-Planck Institute for Bioinorganic Chemistry in Mulheim. Berry is lead author of the paper describing the new compound, which was originally published in Science Magazine's online publication, Science Express (http://www.sciencemag.org/cgi/content/abstract/1128506v1).

The research team, which included scientists from the Max-Planck Institute for Bioinorganic Chemistry in Germany and the Stanford Synchrotron Radiation Laboratory, conducted x-ray absorption spectroscopy (XAS) experimemts at SSRL's beamline 9-3 to characterize their discovery. The XAS studies, combined with other spectroscopic results and calculations, were key in establishing that the structure of this novel compound.

To learn more about this research see the full technical highlight at:
http://www-ssrl.slac.stanford.edu/ research/highlights_archive/fe6.html

J. F. Berry, E. Bill, E. Bothe, S. DeBeer George, B. Mienert, B. F. Neese, K. Wieghardt, Science 2006, 312, 1937.