Materials Data on TbAlCu4 by Materials Project
TbCu4Al crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. Tb is bonded in a 6-coordinate geometry to fifteen Cu and three equivalent Al atoms. There are three shorter (2.99 Å) and twelve longer (3.28 Å) Tb–Cu bond lengths. All Tb–Al bond lengths are 2.99 Å. There are two inequivalent Cu sites. In the first Cu site, Cu is bonded to three equivalent Tb, six equivalent Cu, and three equivalent Al atoms to form CuTb3Al3Cu6 cuboctahedra that share corners with nine equivalent AlTb3Cu9 cuboctahedra, corners with twelve equivalent CuTb4Al2Cu6 cuboctahedra, edges with six equivalent CuTb3Al3Cu6 cuboctahedra, faces with three equivalent AlTb3Cu9 cuboctahedra, and faces with twenty CuTb3Al3Cu6 cuboctahedra. All Cu–Cu bond lengths are 2.51 Å. All Cu–Al bond lengths are 2.99 Å. In the second Cu site, Cu is bonded to four equivalent Tb, six Cu, and two equivalent Al atoms to form distorted CuTb4Al2Cu6 cuboctahedra that share corners with four equivalent AlTb3Cu9 cuboctahedra, corners with twenty CuTb3Al3Cu6 cuboctahedra, edges with ten equivalent CuTb4Al2Cu6 cuboctahedra, faces with six equivalent AlTb3Cu9 cuboctahedra, and faces with sixteen CuTb3Al3Cu6 cuboctahedra. There are two shorter (2.58 Å) and two longer (2.61 Å) Cu–Cu bond lengths. Both Cu–Al bond lengths are 2.52 Å. Al is bonded to three equivalent Tb and nine Cu atoms to form distorted AlTb3Cu9 cuboctahedra that share corners with twenty-one CuTb3Al3Cu6 cuboctahedra, edges with six equivalent AlTb3Cu9 cuboctahedra, faces with two equivalent AlTb3Cu9 cuboctahedra, and faces with twenty-one CuTb3Al3Cu6 cuboctahedra.