CaNi3 crystallizes in the trigonal R-3m space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 12-coordinate geometry to three equivalent Ni(3) and nine equivalent Ni(1) atoms. In the second Ca site, Ca(2) is bonded in a 18-coordinate geometry to six equivalent Ni(2) and twelve equivalent Ni(1) atoms. There are three inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent Ca(2), three equivalent Ca(1), one Ni(3), two equivalent Ni(2), and four equivalent Ni(1) atoms to form NiCa5Ni7 cuboctahedra that share corners with two equivalent Ni(3)Ca6Ni6 cuboctahedra, corners with fifteen equivalent Ni(1)Ca5Ni7 cuboctahedra, edges with eight equivalent Ni(1)Ca5Ni7 cuboctahedra, faces with three equivalent Ni(3)Ca6Ni6 cuboctahedra, and faces with eleven equivalent Ni(1)Ca5Ni7 cuboctahedra. In the second Ni site, Ni(2) is bonded in a 9-coordinate geometry to three equivalent Ca(2) and six equivalent Ni(1) atoms. In the third Ni site, Ni(3) is bonded to six equivalent Ca(1) and six equivalent Ni(1) atoms to form NiCa6Ni6 cuboctahedra that share corners with twelve equivalent Ni(1)Ca5Ni7 cuboctahedra, edges with six equivalent Ni(3)Ca6Ni6 cuboctahedra, and faces with eighteen equivalent Ni(1)Ca5Ni7 cuboctahedra.
CaNi3 crystallizes in the trigonal R-3m space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 12-coordinate geometry to three equivalent Ni(3) and nine equivalent Ni(1) atoms. All Ca(1)-Ni(3) bond lengths are 2.94 Å. There are six shorter (2.87 Å) and three longer (3.05 Å) Ca(1)-Ni(1) bond lengths. In the second Ca site, Ca(2) is bonded in a 18-coordinate geometry to six equivalent Ni(2) and twelve equivalent Ni(1) atoms. All Ca(2)-Ni(2) bond lengths are 2.87 Å. All Ca(2)-Ni(1) bond lengths are 3.16 Å. There are three inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent Ca(2), three equivalent Ca(1), one Ni(3), two equivalent Ni(2), and four equivalent Ni(1) atoms to form NiCa5Ni7 cuboctahedra that share corners with two equivalent Ni(3)Ca6Ni6 cuboctahedra, corners with fifteen equivalent Ni(1)Ca5Ni7 cuboctahedra, edges with eight equivalent Ni(1)Ca5Ni7 cuboctahedra, faces with three equivalent Ni(3)Ca6Ni6 cuboctahedra, and faces with eleven equivalent Ni(1)Ca5Ni7 cuboctahedra. The Ni(1)-Ni(3) bond length is 2.50 Å. There is one shorter (2.41 Å) and one longer (2.43 Å) Ni(1)-Ni(2) bond length. There are two shorter (2.48 Å) and two longer (2.50 Å) Ni(1)-Ni(1) bond lengths. In the second Ni site, Ni(2) is bonded in a 9-coordinate geometry to three equivalent Ca(2) and six equivalent Ni(1) atoms. In the third Ni site, Ni(3) is bonded to six equivalent Ca(1) and six equivalent Ni(1) atoms to form NiCa6Ni6 cuboctahedra that share corners with twelve equivalent Ni(1)Ca5Ni7 cuboctahedra, edges with six equivalent Ni(3)Ca6Ni6 cuboctahedra, and faces with eighteen equivalent Ni(1)Ca5Ni7 cuboctahedra.