DOE OSTI2020
Ni15Cu4Ga is alpha La-derived structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. there are six inequivalent Ni sites. In the first Ni site, Ni is bonded to eight equivalent Ni and four equivalent Ga atoms to form NiGa4Ni8 cuboctahedra that share corners with twelve NiGa4Ni8 cuboctahedra, edges with eight equivalent CuNi12 cuboctahedra, edges with sixteen equivalent NiGa2Cu2Ni8 cuboctahedra, faces with four equivalent GaNi12 cuboctahedra, and faces with fourteen NiGa2Cu2Ni8 cuboctahedra. All Ni–Ni bond lengths are 2.51 Å. All Ni–Ga bond lengths are 2.51 Å. In the second Ni site, Ni is bonded to eight Ni and four equivalent Cu atoms to form NiCu4Ni8 cuboctahedra that share corners with twelve NiGa4Ni8 cuboctahedra, edges with four equivalent CuNi12 cuboctahedra, edges with four equivalent GaNi12 cuboctahedra, edges with sixteen NiCu4Ni8 cuboctahedra, faces with four equivalent CuNi12 cuboctahedra, and faces with fourteen NiGa4Ni8 cuboctahedra. All Ni–Ni bond lengths are 2.50 Å. All Ni–Cu bond lengths are 2.51 Å. In the third Ni site, Ni is bonded to eight Ni and four equivalent Cu atoms to form NiCu4Ni8 cuboctahedra that share corners with twelve NiCu4Ni8 cuboctahedra, edges with eight CuNi12 cuboctahedra, edges with sixteen NiCu4Ni8 cuboctahedra, faces with four equivalent CuNi12 cuboctahedra, and faces with fourteen NiCu4Ni8 cuboctahedra. All Ni–Ni bond lengths are 2.50 Å. All Ni–Cu bond lengths are 2.51 Å. In the fourth Ni site, Ni is bonded to eight Ni, two equivalent Cu, and two equivalent Ga atoms to form NiGa2Cu2Ni8 cuboctahedra that share corners with twelve NiGa2Cu2Ni8 cuboctahedra, edges with four equivalent CuNi12 cuboctahedra, edges with four equivalent GaNi12 cuboctahedra, edges with sixteen NiGa4Ni8 cuboctahedra, faces with two equivalent CuNi12 cuboctahedra, faces with two equivalent GaNi12 cuboctahedra, and faces with fourteen NiGa4Ni8 cuboctahedra. All Ni–Ni bond lengths are 2.51 Å. Both Ni–Cu bond lengths are 2.50 Å. Both Ni–Ga bond lengths are 2.51 Å. In the fifth Ni site, Ni is bonded to eight Ni and four Cu atoms to form NiCu4Ni8 cuboctahedra that share corners with twelve NiGa2Cu2Ni8 cuboctahedra, edges with eight CuNi12 cuboctahedra, edges with sixteen NiCu4Ni8 cuboctahedra, faces with four CuNi12 cuboctahedra, and faces with fourteen NiCu4Ni8 cuboctahedra. All Ni–Ni bond lengths are 2.51 Å. All Ni–Cu bond lengths are 2.50 Å. In the sixth Ni site, Ni is bonded to eight Ni and four equivalent Cu atoms to form NiCu4Ni8 cuboctahedra that share corners with twelve NiCu4Ni8 cuboctahedra, edges with eight equivalent CuNi12 cuboctahedra, edges with sixteen NiCu4Ni8 cuboctahedra, faces with four equivalent CuNi12 cuboctahedra, and faces with fourteen NiCu4Ni8 cuboctahedra. All Ni–Ni bond lengths are 2.51 Å. All Ni–Cu bond lengths are 2.50 Å. There are two inequivalent Cu sites. In the first Cu site, Cu is bonded to twelve Ni atoms to form CuNi12 cuboctahedra that share corners with four equivalent GaNi12 cuboctahedra, corners with eight CuNi12 cuboctahedra, edges with twenty-four NiGa2Cu2Ni8 cuboctahedra, a faceface with one GaNi12 cuboctahedra, faces with five CuNi12 cuboctahedra, and faces with twelve NiCu4Ni8 cuboctahedra. In the second Cu site, Cu is bonded to twelve Ni atoms to form CuNi12 cuboctahedra that share corners with twelve CuNi12 cuboctahedra, edges with twenty-four NiCu4Ni8 cuboctahedra, faces with six CuNi12 cuboctahedra, and faces with twelve NiCu4Ni8 cuboctahedra. Ga is bonded to twelve Ni atoms to form GaNi12 cuboctahedra that share corners with four equivalent GaNi12 cuboctahedra, corners with eight equivalent CuNi12 cuboctahedra, edges with twenty-four NiGa2Cu2Ni8 cuboctahedra, faces with two equivalent CuNi12 cuboctahedra, faces with four equivalent GaNi12 cuboctahedra, and faces with twelve NiGa2Cu2Ni8 cuboctahedra.