Ca3Mg2Ni13 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 distorted hexagonal planar geometry to two equivalent Mg(1), six equivalent Ni(1), and twelve equivalent Ni(2) atoms. In the second Ca site, Ca(2) is bonded in a 16-coordinate geometry to one Ca(2), three equivalent Mg(1), three equivalent Ni(2), three equivalent Ni(3), and six equivalent Ni(4) atoms. Mg(1) is bonded in a 16-coordinate geometry to one Ca(1), three equivalent Ca(2), three equivalent Ni(3), three equivalent Ni(4), and six equivalent Ni(2) atoms. There are four inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 9-coordinate geometry to three equivalent Ca(1) and six equivalent Ni(2) atoms. In the second Ni site, Ni(2) is bonded to one Ca(2), two equivalent Ca(1), two equivalent Mg(1), one Ni(3), two equivalent Ni(1), and four equivalent Ni(2) atoms to form NiCa3Mg2Ni7 cuboctahedra that share corners with two equivalent Ni(3)Ca3Mg3Ni6 cuboctahedra, corners with five equivalent Ni(4)Ca4Mg2Ni6 cuboctahedra, corners with ten equivalent Ni(2)Ca3Mg2Ni7 cuboctahedra, edges with two equivalent Ni(4)Ca4Mg2Ni6 cuboctahedra, edges with six equivalent Ni(2)Ca3Mg2Ni7 cuboctahedra, faces with two equivalent Ni(4)Ca4Mg2Ni6 cuboctahedra, faces with three equivalent Ni(3)Ca3Mg3Ni6 cuboctahedra, and faces with nine equivalent Ni(2)Ca3Mg2Ni7 cuboctahedra. In the third Ni site, Ni(3) is bonded to three equivalent Ca(2), three equivalent Mg(1), three equivalent Ni(2), and three equivalent Ni(4) atoms to form NiCa3Mg3Ni6 cuboctahedra that share corners with three equivalent Ni(3)Ca3Mg3Ni6 cuboctahedra, corners with six equivalent Ni(2)Ca3Mg2Ni7 cuboctahedra, corners with six equivalent Ni(4)Ca4Mg2Ni6 cuboctahedra, edges with six equivalent Ni(3)Ca3Mg3Ni6 cuboctahedra, faces with nine equivalent Ni(2)Ca3Mg2Ni7 cuboctahedra, and faces with nine equivalent Ni(4)Ca4Mg2Ni6 cuboctahedra. In the fourth Ni site, Ni(4) is bonded to four equivalent Ca(2), two equivalent Mg(1), two equivalent Ni(3), and four equivalent Ni(4) atoms to form NiCa4Mg2Ni6 cuboctahedra that share corners with four equivalent Ni(3)Ca3Mg3Ni6 cuboctahedra, corners with four equivalent Ni(4)Ca4Mg2Ni6 cuboctahedra, corners with ten equivalent Ni(2)Ca3Mg2Ni7 cuboctahedra, edges with two equivalent Ni(4)Ca4Mg2Ni6 cuboctahedra, edges with four equivalent Ni(2)Ca3Mg2Ni7 cuboctahedra, faces with four equivalent Ni(2)Ca3Mg2Ni7 cuboctahedra, faces with six equivalent Ni(3)Ca3Mg3Ni6 cuboctahedra, and faces with eight equivalent Ni(4)Ca4Mg2Ni6 cuboctahedra.
Ca3Mg2Ni13 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 distorted hexagonal planar geometry to two equivalent Mg(1), six equivalent Ni(1), and twelve equivalent Ni(2) atoms. Both Ca(1)-Mg(1) bond lengths are 3.33 Å. All Ca(1)-Ni(1) bond lengths are 2.84 Å. All Ca(1)-Ni(2) bond lengths are 3.15 Å. In the second Ca site, Ca(2) is bonded in a 16-coordinate geometry to one Ca(2), three equivalent Mg(1), three equivalent Ni(2), three equivalent Ni(3), and six equivalent Ni(4) atoms. The Ca(2)-Ca(2) bond length is 3.06 Å. All Ca(2)-Mg(1) bond lengths are 3.06 Å. All Ca(2)-Ni(2) bond lengths are 2.87 Å. All Ca(2)-Ni(3) bond lengths are 2.88 Å. All Ca(2)-Ni(4) bond lengths are 2.90 Å. Mg(1) is bonded in a 16-coordinate geometry to one Ca(1), three equivalent Ca(2), three equivalent Ni(3), three equivalent Ni(4), and six equivalent Ni(2) atoms. All Mg(1)-Ni(3) bond lengths are 2.92 Å. All Mg(1)-Ni(4) bond lengths are 3.01 Å. All Mg(1)-Ni(2) bond lengths are 2.81 Å. There are four inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 9-coordinate geometry to three equivalent Ca(1) and six equivalent Ni(2) atoms. There are three shorter (2.41 Å) and three longer (2.44 Å) Ni(1)-Ni(2) bond lengths. In the second Ni site, Ni(2) is bonded to one Ca(2), two equivalent Ca(1), two equivalent Mg(1), one Ni(3), two equivalent Ni(1), and four equivalent Ni(2) atoms to form NiCa3Mg2Ni7 cuboctahedra that share corners with two equivalent Ni(3)Ca3Mg3Ni6 cuboctahedra, corners with five equivalent Ni(4)Ca4Mg2Ni6 cuboctahedra, corners with ten equivalent Ni(2)Ca3Mg2Ni7 cuboctahedra, edges with two equivalent Ni(4)Ca4Mg2Ni6 cuboctahedra, edges with six equivalent Ni(2)Ca3Mg2Ni7 cuboctahedra, faces with two equivalent Ni(4)Ca4Mg2Ni6 cuboctahedra, faces with three equivalent Ni(3)Ca3Mg3Ni6 cuboctahedra, and faces with nine equivalent Ni(2)Ca3Mg2Ni7 cuboctahedra. The Ni(2)-Ni(3) bond length is 2.46 Å. There are two shorter (2.45 Å) and two longer (2.48 Å) Ni(2)-Ni(2) bond lengths. In the third Ni site, Ni(3) is bonded to three equivalent Ca(2), three equivalent Mg(1), three equivalent Ni(2), and three equivalent Ni(4) atoms to form NiCa3Mg3Ni6 cuboctahedra that share corners with three equivalent Ni(3)Ca3Mg3Ni6 cuboctahedra, corners with six equivalent Ni(2)Ca3Mg2Ni7 cuboctahedra, corners with six equivalent Ni(4)Ca4Mg2Ni6 cuboctahedra, edges with six equivalent Ni(3)Ca3Mg3Ni6 cuboctahedra, faces with nine equivalent Ni(2)Ca3Mg2Ni7 cuboctahedra, and faces with nine equivalent Ni(4)Ca4Mg2Ni6 cuboctahedra. All Ni(3)-Ni(4) bond lengths are 2.46 Å. In the fourth Ni site, Ni(4) is bonded to four equivalent Ca(2), two equivalent Mg(1), two equivalent Ni(3), and four equivalent Ni(4) atoms to form NiCa4Mg2Ni6 cuboctahedra that share corners with four equivalent Ni(3)Ca3Mg3Ni6 cuboctahedra, corners with four equivalent Ni(4)Ca4Mg2Ni6 cuboctahedra, corners with ten equivalent Ni(2)Ca3Mg2Ni7 cuboctahedra, edges with two equivalent Ni(4)Ca4Mg2Ni6 cuboctahedra, edges with four equivalent Ni(2)Ca3Mg2Ni7 cuboctahedra, faces with four equivalent Ni(2)Ca3Mg2Ni7 cuboctahedra, faces with six equivalent Ni(3)Ca3Mg3Ni6 cuboctahedra, and faces with eight equivalent Ni(4)Ca4Mg2Ni6 cuboctahedra. All Ni(4)-Ni(4) bond lengths are 2.46 Å.