DOE OSTI2020
GdCu9In2 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. Gd is bonded in a 12-coordinate geometry to sixteen Cu and four equivalent In atoms. There are eight shorter (3.10 Å) and eight longer (3.35 Å) Gd–Cu bond lengths. All Gd–In bond lengths are 3.34 Å. There are three inequivalent Cu sites. In the first Cu site, Cu is bonded to eight Cu and four equivalent In atoms to form CuIn4Cu8 cuboctahedra that share corners with sixteen CuGd2In2Cu8 cuboctahedra, edges with two equivalent CuIn4Cu8 cuboctahedra, and faces with twenty CuGd2In3Cu7 cuboctahedra. There are four shorter (2.48 Å) and four longer (2.56 Å) Cu–Cu bond lengths. All Cu–In bond lengths are 2.93 Å. In the second Cu site, Cu is bonded to two equivalent Gd, eight Cu, and two equivalent In atoms to form distorted CuGd2In2Cu8 cuboctahedra that share corners with twenty CuIn4Cu8 cuboctahedra, edges with six CuGd2In3Cu7 cuboctahedra, and faces with nineteen CuIn4Cu8 cuboctahedra. There are a spread of Cu–Cu bond distances ranging from 2.54–2.79 Å. Both Cu–In bond lengths are 2.96 Å. In the third Cu site, Cu is bonded to two equivalent Gd, seven Cu, and three equivalent In atoms to form distorted CuGd2In3Cu7 cuboctahedra that share corners with eighteen CuIn4Cu8 cuboctahedra, edges with nine CuGd2In2Cu8 cuboctahedra, and faces with twenty CuIn4Cu8 cuboctahedra. There are one shorter (2.48 Å) and one longer (2.56 Å) Cu–Cu bond lengths. There are one shorter (2.67 Å) and two longer (2.87 Å) Cu–In bond lengths. In is bonded in a 6-coordinate geometry to two equivalent Gd, twelve Cu, and one In atom. The In–In bond length is 2.97 Å.