A New Discovery of FeBi2

Figure Caption: Crystal structure of FeBi<sub>2</sub>, determined at HPCAT 16-ID-B at 30 GPa, where Fe is represented by red spheres and Bi, by purple spheres. This phase possesses the first known bond between Fe and Bi.
Figure Caption: Crystal structure of FeBi2, determined at HPCAT 16-ID-B at 30 GPa, where Fe is represented by red spheres and Bi, by purple spheres. This phase possesses the first known bond between Fe and Bi.

Among thousands of known chemical interactions between common elements in the periodic table, there remain bonds that are curiously absent. Iron-bismuth is such a system, exhibiting complete immiscibility even in the liquid state. Using laser-heated diamond anvil cells, recent experiments at HPCAT have revealed a new form of intermetallic FeBi2. The new material, formed at 1500 K and 30 GPa, possesses the Al2Cu-type structure featuring Fe coordinated by eight Bi atoms in face-sharing square antiprisms along the c-axis. By combining the paramagnetism of iron with the spin-orbit coupling inherent to bismuth, the new material may display transformative magnetic properties. This research, conducted at beamline 16-ID-B, is a collaboration between Danna Freedman (Chemistry) and Steve Jacobsen (Earth and Planetary Sciences) from Northwestern and Yue Meng (Carnegie Institution of Washington). Published in: Walsh et al.,  ACS Cent. Sci., 2016, 2 (11), pp 867–871