Materials Data on Be4AlCr by Materials Project

Be4CrAl crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. there are three inequivalent Be sites. In the first Be site, Be is bonded to six equivalent Be and six equivalent Al atoms to form BeBe6Al6 cuboctahedra that share corners with twelve equivalent BeBe6Al3Cr3 cuboctahedra, edges with six equivalent BeBe6Al6 cuboctahedra, and faces with twenty BeBe6Cr6 cuboctahedra. All Be–Be bond lengths are 2.21 Å. All Be–Al bond lengths are 2.56 Å. In the second Be site, Be is bonded to six equivalent Be and six equivalent Cr atoms to form BeBe6Cr6 cuboctahedra that share corners with twelve equivalent BeBe6Al3Cr3 cuboctahedra, edges with six equivalent BeBe6Cr6 cuboctahedra, and faces with twenty BeBe6Al6 cuboctahedra. All Be–Be bond lengths are 2.11 Å. All Be–Cr bond lengths are 2.53 Å. In the third Be site, Be is bonded to six Be, three equivalent Cr, and three equivalent Al atoms to form BeBe6Al3Cr3 cuboctahedra that share corners with eighteen BeBe6Al6 cuboctahedra, edges with six equivalent BeBe6Al3Cr3 cuboctahedra, and faces with eighteen BeBe6Al6 cuboctahedra. There are two shorter (2.14 Å) and two longer (2.19 Å) Be–Be bond lengths. There are one shorter (2.40 Å) and two longer (2.54 Å) Be–Cr bond lengths. There are two shorter (2.51 Å) and one longer (2.65 Å) Be–Al bond lengths. Cr is bonded in a 12-coordinate geometry to twelve Be, three equivalent Cr, and one Al atom. All Cr–Cr bond lengths are 2.61 Å. The Cr–Al bond length is 2.60 Å. Al is bonded in a 10-coordinate geometry to twelve Be, one Cr, and three equivalent Al atoms. All Al–Al bond lengths are 2.72 Å.