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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on U(Al2Cr)4 by Materials Project

UCr4Al8 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. U is bonded in a 12-coordinate geometry to eight equivalent Cr and twelve Al atoms. All U–Cr bond lengths are 3.38 Å. There are four shorter (3.03 Å) and eight longer (3.15 Å) U–Al bond lengths. Cr is bonded to two equivalent U, two equivalent Cr, and eight Al atoms to form a mixture of distorted edge, face, and corner-sharing CrU2Al8Cr2 cuboctahedra. Both Cr–Cr bond lengths are 2.50 Å. There are four shorter (2.56 Å) and four longer (2.67 Å) Cr–Al bond lengths. There are two inequivalent Al sites. In the first Al site, Al is bonded in a 10-coordinate geometry to one U, four equivalent Cr, and five Al atoms. There are a spread of Al–Al bond distances ranging from 2.73–2.88 Å. In the second Al site, Al is bonded in a 12-coordinate geometry to two equivalent U, four equivalent Cr, and six Al atoms. Both Al–Al bond lengths are 2.72 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U(Al10Cr)2 by Materials Project

U(CrAl10)2 crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. U is bonded in a 4-coordinate geometry to sixteen Al atoms. There are four shorter (3.11 Å) and twelve longer (3.17 Å) U–Al bond lengths. Cr is bonded to twelve Al atoms to form CrAl12 cuboctahedra that share corners with six equivalent CrAl12 cuboctahedra, edges with eighteen equivalent AlUAl10Cr cuboctahedra, and faces with six equivalent AlUAl10Cr cuboctahedra. There are six shorter (2.54 Å) and six longer (2.78 Å) Cr–Al bond lengths. There are three inequivalent Al sites. In the first Al site, Al is bonded in a distorted linear geometry to two equivalent U and twelve equivalent Al atoms. All Al–Al bond lengths are 3.07 Å. In the second Al site, Al is bonded in a 12-coordinate geometry to two equivalent Cr and ten Al atoms. There are a spread of Al–Al bond distances ranging from 2.70–2.82 Å. In the third Al site, Al is bonded to one U, one Cr, and ten Al atoms to form distorted AlUAl10Cr cuboctahedra that share corners with fifteen equivalent AlUAl10Cr cuboctahedra, edges with two equivalent AlUAl10Cr cuboctahedra, edges with three equivalent CrAl12 cuboctahedra, a faceface with one CrAl12 cuboctahedra, and faces with fifteen equivalent AlUAl10Cr cuboctahedra. There are a spread of Al–Al bond distances ranging from 2.68–2.90 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U(Al10Cr)2 by Materials Project

U(CrAl10)2 crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. U is bonded in a 4-coordinate geometry to four equivalent Cr and twelve equivalent Al atoms. All U–Cr bond lengths are 3.17 Å. All U–Al bond lengths are 3.16 Å. Cr is bonded in a 2-coordinate geometry to two equivalent U and twelve equivalent Al atoms. All Cr–Al bond lengths are 3.08 Å. There are three inequivalent Al sites. In the first Al site, Al is bonded to twelve Al atoms to form a mixture of distorted face, edge, and corner-sharing AlAl12 cuboctahedra. There are a spread of Al–Al bond distances ranging from 2.59–2.93 Å. In the second Al site, Al is bonded to twelve Al atoms to form a mixture of face, edge, and corner-sharing AlAl12 cuboctahedra. All Al–Al bond lengths are 2.91 Å. In the third Al site, Al is bonded to one U, two equivalent Cr, and nine Al atoms to form a mixture of distorted face, edge, and corner-sharing AlUAl9Cr2 cuboctahedra. There are a spread of Al–Al bond distances ranging from 2.63–3.02 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U6Al43Cr4 by Materials Project

U6Cr4Al43 is Hexagonal Laves-derived structured and crystallizes in the hexagonal P6_3/mcm space group. The structure is three-dimensional. U is bonded in a 2-coordinate geometry to one U, one Cr, and fifteen Al atoms. The U–U bond length is 3.02 Å. The U–Cr bond length is 3.65 Å. There are a spread of U–Al bond distances ranging from 3.00–3.52 Å. There are two inequivalent Cr sites. In the first Cr site, Cr is bonded in a distorted q6 geometry to two equivalent U and ten Al atoms. There are a spread of Cr–Al bond distances ranging from 2.52–2.64 Å. In the second Cr site, Cr is bonded to twelve Al atoms to form CrAl12 cuboctahedra that share faces with six equivalent AlU2Al9Cr cuboctahedra. There are six shorter (2.63 Å) and six longer (2.79 Å) Cr–Al bond lengths. There are seven inequivalent Al sites. In the first Al site, Al is bonded in a 12-coordinate geometry to one U, two Cr, and nine Al atoms. There are a spread of Al–Al bond distances ranging from 2.68–2.98 Å. In the second Al site, Al is bonded in a 12-coordinate geometry to four equivalent U and eight Al atoms. There are a spread of Al–Al bond distances ranging from 2.71–3.03 Å. In the third Al site, Al is bonded in a 12-coordinate geometry to two equivalent U, one Cr, and nine Al atoms. There are a spread of Al–Al bond distances ranging from 2.69–3.05 Å. In the fourth Al site, Al is bonded in a 2-coordinate geometry to two equivalent Cr and ten Al atoms. Both Al–Al bond lengths are 2.78 Å. In the fifth Al site, Al is bonded to two equivalent U, one Cr, and nine Al atoms to form distorted AlU2Al9Cr cuboctahedra that share a cornercorner with one AlU2Al9Cr cuboctahedra, edges with three AlU2Al9Cr cuboctahedra, a faceface with one CrAl12 cuboctahedra, and faces with six AlU2Al9Cr cuboctahedra. Both Al–Al bond lengths are 2.92 Å. In the sixth Al site, Al is bonded to three equivalent U and nine Al atoms to form AlU3Al9 cuboctahedra that share corners with three equivalent AlU3Al9 cuboctahedra, edges with three equivalent AlU2Al9Cr cuboctahedra, and faces with five AlU2Al9Cr cuboctahedra. All Al–Al bond lengths are 2.80 Å. In the seventh Al site, Al is bonded in a 10-coordinate geometry to two equivalent U, one Cr, and seven Al atoms. The Al–Al bond length is 2.64 Å.

36 MATERIALS SCIENCE↗