DOE OSTI2020
Be5(FeAl2)2 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are three inequivalent Be sites. In the first Be site, Be is bonded to four Be, two equivalent Fe, and six Al atoms to form a mixture of distorted edge, corner, and face-sharing BeBe4Al6Fe2 cuboctahedra. There are two shorter (2.18 Å) and two longer (2.19 Å) Be–Be bond lengths. Both Be–Fe bond lengths are 2.26 Å. There are four shorter (2.64 Å) and two longer (2.65 Å) Be–Al bond lengths. In the second Be site, Be is bonded in a 2-coordinate geometry to two equivalent Fe and four equivalent Al atoms. Both Be–Fe bond lengths are 2.23 Å. There are two shorter (2.47 Å) and two longer (2.81 Å) Be–Al bond lengths. In the third Be site, Be is bonded to four equivalent Be, two equivalent Fe, and six Al atoms to form a mixture of distorted edge, corner, and face-sharing BeBe4Al6Fe2 cuboctahedra. Both Be–Fe bond lengths are 2.24 Å. There are two shorter (2.61 Å) and four longer (2.65 Å) Be–Al bond lengths. Fe is bonded in a distorted q6 geometry to five Be and six Al atoms. There are a spread of Fe–Al bond distances ranging from 2.50–2.59 Å. There are two inequivalent Al sites. In the first Al site, Al is bonded in a 3-coordinate geometry to six Be, three equivalent Fe, and three equivalent Al atoms. There are two shorter (2.64 Å) and one longer (2.67 Å) Al–Al bond lengths. In the second Al site, Al is bonded in a 1-coordinate geometry to seven Be, three equivalent Fe, and four Al atoms. The Al–Al bond length is 2.99 Å.