DOE OSTI2020
PrAl4 crystallizes in the orthorhombic Imm2 space group. The structure is three-dimensional. there are two inequivalent Pr sites. In the first Pr site, Pr is bonded in a 8-coordinate geometry to sixteen Al atoms. There are a spread of Pr–Al bond distances ranging from 3.28–3.62 Å. In the second Pr site, Pr is bonded in a 8-coordinate geometry to sixteen Al atoms. There are a spread of Pr–Al bond distances ranging from 3.28–3.60 Å. There are eight inequivalent Al sites. In the first Al site, Al is bonded in a 9-coordinate geometry to four equivalent Pr and five Al atoms. There are a spread of Al–Al bond distances ranging from 2.54–2.67 Å. In the second Al site, Al is bonded in a 9-coordinate geometry to four equivalent Pr and five Al atoms. There are two shorter (2.65 Å) and two longer (2.66 Å) Al–Al bond lengths. In the third Al site, Al is bonded to four Pr and eight Al atoms to form a mixture of distorted edge, face, and corner-sharing AlPr4Al8 cuboctahedra. There are two shorter (2.65 Å) and four longer (3.06 Å) Al–Al bond lengths. In the fourth Al site, Al is bonded to four Pr and eight Al atoms to form a mixture of distorted edge, face, and corner-sharing AlPr4Al8 cuboctahedra. There are two shorter (2.65 Å) and four longer (3.01 Å) Al–Al bond lengths. In the fifth Al site, Al is bonded to four Pr and eight Al atoms to form a mixture of distorted edge, face, and corner-sharing AlPr4Al8 cuboctahedra. There are three shorter (2.66 Å) and two longer (3.03 Å) Al–Al bond lengths. In the sixth Al site, Al is bonded in a 9-coordinate geometry to four Pr and five Al atoms. There are one shorter (2.55 Å) and two longer (2.66 Å) Al–Al bond lengths. In the seventh Al site, Al is bonded in a 9-coordinate geometry to four Pr and five Al atoms. The Al–Al bond length is 2.65 Å. In the eighth Al site, Al is bonded to four Pr and eight Al atoms to form a mixture of distorted edge, face, and corner-sharing AlPr4Al8 cuboctahedra.