Materials Data on UMnAl by Materials Project
UMnAl is Frank-Kasper $\mu$ Phase-derived structured and crystallizes in the orthorhombic Imma space group. The structure is three-dimensional. U is bonded in a 2-coordinate geometry to two equivalent U, six equivalent Mn, and six equivalent Al atoms. Both U–U bond lengths are 2.86 Å. There are two shorter (2.74 Å) and four longer (3.13 Å) U–Mn bond lengths. There are four shorter (3.11 Å) and two longer (3.15 Å) U–Al bond lengths. Mn is bonded to six equivalent U, two equivalent Mn, and four equivalent Al atoms to form distorted MnU6Mn2Al4 cuboctahedra that share corners with eight equivalent AlU6Mn4Al2 cuboctahedra, corners with ten equivalent MnU6Mn2Al4 cuboctahedra, edges with six equivalent MnU6Mn2Al4 cuboctahedra, faces with six equivalent MnU6Mn2Al4 cuboctahedra, and faces with twelve equivalent AlU6Mn4Al2 cuboctahedra. Both Mn–Mn bond lengths are 2.76 Å. All Mn–Al bond lengths are 2.57 Å. Al is bonded to six equivalent U, four equivalent Mn, and two equivalent Al atoms to form AlU6Mn4Al2 cuboctahedra that share corners with eight equivalent MnU6Mn2Al4 cuboctahedra, corners with ten equivalent AlU6Mn4Al2 cuboctahedra, edges with six equivalent AlU6Mn4Al2 cuboctahedra, faces with six equivalent AlU6Mn4Al2 cuboctahedra, and faces with twelve equivalent MnU6Mn2Al4 cuboctahedra. Both Al–Al bond lengths are 2.57 Å.