Sm2Ni7 crystallizes in the trigonal R-3m space group. There are seven inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 18-coordinate geometry to three equivalent Ni(2), three equivalent Ni(3), six equivalent Ni(4), and six equivalent Ni(5) atoms. In the second Sm site, Sm(1) is bonded in a 18-coordinate geometry to three equivalent Ni(2); three equivalent Ni(3); six Ni(4,4); and six equivalent Ni(5) atoms. In the third Sm site, Sm(2) is bonded in a 12-coordinate geometry to three equivalent Ni(1) and nine equivalent Ni(5) atoms. In the fourth Sm site, Sm(1) is bonded in a 18-coordinate geometry to three equivalent Ni(2); three equivalent Ni(3); six Ni(4,4); and six equivalent Ni(5) atoms. In the fifth Sm site, Sm(1) is bonded in a 18-coordinate geometry to three equivalent Ni(2); three equivalent Ni(3); six Ni(4,4); and six equivalent Ni(5) atoms. In the sixth Sm site, Sm(1) is bonded in a 18-coordinate geometry to three equivalent Ni(2); three equivalent Ni(3); six Ni(4,4); and six equivalent Ni(5) atoms. In the seventh Sm site, Sm(1) is bonded in a 18-coordinate geometry to three equivalent Ni(2), three equivalent Ni(3), six equivalent Ni(4), and six equivalent Ni(5) atoms. There are eight inequivalent Ni sites. In the first Ni site, Ni(4) is bonded to four Sm(1,1); two equivalent Ni(2); two equivalent Ni(3); and four Ni(4,4) atoms to form NiSm4Ni8 cuboctahedra that share corners with four equivalent Ni(4)Sm4Ni8 cuboctahedra; corners with twelve equivalent Ni(5)Sm5Ni7 cuboctahedra; edges with two equivalent Ni(4)Sm4Ni8 cuboctahedra; edges with eight equivalent Ni(5)Sm5Ni7 cuboctahedra; faces with two equivalent Ni(5)Sm5Ni7 cuboctahedra; and faces with eight Ni(4,4)Sm4Ni8 cuboctahedra. In the second Ni site, Ni(1) is bonded to six equivalent Sm(2) and six equivalent Ni(5) atoms to form NiSm6Ni6 cuboctahedra that share corners with twelve equivalent Ni(5)Sm5Ni7 cuboctahedra, edges with six equivalent Ni(1)Sm6Ni6 cuboctahedra, and faces with eighteen equivalent Ni(5)Sm5Ni7 cuboctahedra. In the third Ni site, Ni(2) is bonded in a 9-coordinate geometry to three equivalent Sm(1); three Ni(4,4); and three equivalent Ni(5) atoms. In the fourth Ni site, Ni(4) is bonded to four Sm(1,1); two equivalent Ni(2); two equivalent Ni(3); and four Ni(4,4) atoms to form NiSm4Ni8 cuboctahedra that share corners with four equivalent Ni(4)Sm4Ni8 cuboctahedra; corners with twelve equivalent Ni(5)Sm5Ni7 cuboctahedra; edges with two equivalent Ni(4)Sm4Ni8 cuboctahedra; edges with eight equivalent Ni(5)Sm5Ni7 cuboctahedra; faces with two equivalent Ni(5)Sm5Ni7 cuboctahedra; and faces with eight Ni(4,4)Sm4Ni8 cuboctahedra. In the fifth Ni site, Ni(3) is bonded in a 9-coordinate geometry to three equivalent Sm(1), three equivalent Ni(4), and three equivalent Ni(5) atoms. In the sixth Ni site, Ni(4) is bonded to four Sm(1,1); two equivalent Ni(2); two equivalent Ni(3); and four equivalent Ni(4) atoms to form NiSm4Ni8 cuboctahedra that share corners with four equivalent Ni(4)Sm4Ni8 cuboctahedra, corners with twelve equivalent Ni(5)Sm5Ni7 cuboctahedra, edges with two equivalent Ni(4)Sm4Ni8 cuboctahedra, edges with eight equivalent Ni(5)Sm5Ni7 cuboctahedra, faces with two equivalent Ni(5)Sm5Ni7 cuboctahedra, and faces with eight equivalent Ni(4)Sm4Ni8 cuboctahedra. In the seventh Ni site, Ni(4) is bonded to four Sm(1,1); two equivalent Ni(2); two equivalent Ni(3); and four equivalent Ni(4) atoms to form NiSm4Ni8 cuboctahedra that share corners with four equivalent Ni(4)Sm4Ni8 cuboctahedra, corners with twelve equivalent Ni(5)Sm5Ni7 cuboctahedra, edges with two equivalent Ni(4)Sm4Ni8 cuboctahedra, edges with eight equivalent Ni(5)Sm5Ni7 cuboctahedra, faces with two equivalent Ni(5)Sm5Ni7 cuboctahedra, and faces with eight equivalent Ni(4)Sm4Ni8 cuboctahedra. In the eighth Ni site, Ni(5) is bonded to two equivalent Sm(1), three equivalent Sm(2), one Ni(1), one Ni(2), one Ni(3), and four equivalent Ni(5) atoms to form distorted NiSm5Ni7 cuboctahedra that share corners with two equivalent Ni(1)Sm6Ni6 cuboctahedra, corners with six equivalent Ni(4)Sm4Ni8 cuboctahedra, corners with nine equivalent Ni(5)Sm5Ni7 cuboctahedra, edges with four equivalent Ni(4)Sm4Ni8 cuboctahedra, edges with four equivalent Ni(5)Sm5Ni7 cuboctahedra,  a faceface with one Ni(4)Sm4Ni8 cuboctahedra, faces with three equivalent Ni(1)Sm6Ni6 cuboctahedra, and faces with ten equivalent Ni(5)Sm5Ni7 cuboctahedra.
Sm2Ni7 crystallizes in the trigonal R-3m space group. There are seven inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 18-coordinate geometry to three equivalent Ni(2), three equivalent Ni(3), six equivalent Ni(4), and six equivalent Ni(5) atoms. All Sm(1)-Ni(2) bond lengths are 2.86 Å. All Sm(1)-Ni(3) bond lengths are 2.86 Å. All Sm(1)-Ni(4) bond lengths are 3.10 Å. All Sm(1)-Ni(5) bond lengths are 3.28 Å. In the second Sm site, Sm(1) is bonded in a 18-coordinate geometry to three equivalent Ni(2); three equivalent Ni(3); six Ni(4,4); and six equivalent Ni(5) atoms. All Sm(1)-Ni(2) bond lengths are 2.86 Å. All Sm(1)-Ni(3) bond lengths are 2.86 Å. All Sm(1)-Ni(4,4) bond lengths are 3.10 Å. All Sm(1)-Ni(5) bond lengths are 3.28 Å. In the third Sm site, Sm(2) is bonded in a 12-coordinate geometry to three equivalent Ni(1) and nine equivalent Ni(5) atoms. All Sm(2)-Ni(1) bond lengths are 2.95 Å. There are six shorter (2.84 Å) and three longer (3.16 Å) Sm(2)-Ni(5) bond lengths. In the fourth Sm site, Sm(1) is bonded in a 18-coordinate geometry to three equivalent Ni(2); three equivalent Ni(3); six Ni(4,4); and six equivalent Ni(5) atoms. All Sm(1)-Ni(2) bond lengths are 2.86 Å. All Sm(1)-Ni(3) bond lengths are 2.86 Å. All Sm(1)-Ni(4,4) bond lengths are 3.10 Å. All Sm(1)-Ni(5) bond lengths are 3.28 Å. In the fifth Sm site, Sm(1) is bonded in a 18-coordinate geometry to three equivalent Ni(2); three equivalent Ni(3); six Ni(4,4); and six equivalent Ni(5) atoms. All Sm(1)-Ni(2) bond lengths are 2.86 Å. All Sm(1)-Ni(3) bond lengths are 2.86 Å. All Sm(1)-Ni(4,4) bond lengths are 3.10 Å. All Sm(1)-Ni(5) bond lengths are 3.28 Å. In the sixth Sm site, Sm(1) is bonded in a 18-coordinate geometry to three equivalent Ni(2); three equivalent Ni(3); six Ni(4,4); and six equivalent Ni(5) atoms. All Sm(1)-Ni(2) bond lengths are 2.86 Å. All Sm(1)-Ni(3) bond lengths are 2.86 Å. All Sm(1)-Ni(4,4) bond lengths are 3.10 Å. All Sm(1)-Ni(5) bond lengths are 3.28 Å. In the seventh Sm site, Sm(1) is bonded in a 18-coordinate geometry to three equivalent Ni(2), three equivalent Ni(3), six equivalent Ni(4), and six equivalent Ni(5) atoms. All Sm(1)-Ni(2) bond lengths are 2.86 Å. All Sm(1)-Ni(3) bond lengths are 2.86 Å. All Sm(1)-Ni(4) bond lengths are 3.10 Å. All Sm(1)-Ni(5) bond lengths are 3.28 Å. There are eight inequivalent Ni sites. In the first Ni site, Ni(4) is bonded to four Sm(1,1); two equivalent Ni(2); two equivalent Ni(3); and four Ni(4,4) atoms to form NiSm4Ni8 cuboctahedra that share corners with four equivalent Ni(4)Sm4Ni8 cuboctahedra; corners with twelve equivalent Ni(5)Sm5Ni7 cuboctahedra; edges with two equivalent Ni(4)Sm4Ni8 cuboctahedra; edges with eight equivalent Ni(5)Sm5Ni7 cuboctahedra; faces with two equivalent Ni(5)Sm5Ni7 cuboctahedra; and faces with eight Ni(4,4)Sm4Ni8 cuboctahedra. Both Ni(4)-Ni(2) bond lengths are 2.47 Å. Both Ni(4)-Ni(3) bond lengths are 2.46 Å. All Ni(4)-Ni(4,4) bond lengths are 2.48 Å. In the second Ni site, Ni(1) is bonded to six equivalent Sm(2) and six equivalent Ni(5) atoms to form NiSm6Ni6 cuboctahedra that share corners with twelve equivalent Ni(5)Sm5Ni7 cuboctahedra, edges with six equivalent Ni(1)Sm6Ni6 cuboctahedra, and faces with eighteen equivalent Ni(5)Sm5Ni7 cuboctahedra. All Ni(1)-Ni(5) bond lengths are 2.54 Å. In the third Ni site, Ni(2) is bonded in a 9-coordinate geometry to three equivalent Sm(1); three Ni(4,4); and three equivalent Ni(5) atoms. The Ni(2)-Ni(4) bond length is 2.47 Å. All Ni(2)-Ni(5) bond lengths are 2.45 Å. In the fourth Ni site, Ni(4) is bonded to four Sm(1,1); two equivalent Ni(2); two equivalent Ni(3); and four Ni(4,4) atoms to form NiSm4Ni8 cuboctahedra that share corners with four equivalent Ni(4)Sm4Ni8 cuboctahedra; corners with twelve equivalent Ni(5)Sm5Ni7 cuboctahedra; edges with two equivalent Ni(4)Sm4Ni8 cuboctahedra; edges with eight equivalent Ni(5)Sm5Ni7 cuboctahedra; faces with two equivalent Ni(5)Sm5Ni7 cuboctahedra; and faces with eight Ni(4,4)Sm4Ni8 cuboctahedra. Both Ni(4)-Ni(2) bond lengths are 2.47 Å. Both Ni(4)-Ni(3) bond lengths are 2.46 Å. All Ni(4)-Ni(4,4) bond lengths are 2.48 Å. In the fifth Ni site, Ni(3) is bonded in a 9-coordinate geometry to three equivalent Sm(1), three equivalent Ni(4), and three equivalent Ni(5) atoms. All Ni(3)-Ni(4) bond lengths are 2.46 Å. All Ni(3)-Ni(5) bond lengths are 2.46 Å. In the sixth Ni site, Ni(4) is bonded to four Sm(1,1); two equivalent Ni(2); two equivalent Ni(3); and four equivalent Ni(4) atoms to form NiSm4Ni8 cuboctahedra that share corners with four equivalent Ni(4)Sm4Ni8 cuboctahedra, corners with twelve equivalent Ni(5)Sm5Ni7 cuboctahedra, edges with two equivalent Ni(4)Sm4Ni8 cuboctahedra, edges with eight equivalent Ni(5)Sm5Ni7 cuboctahedra, faces with two equivalent Ni(5)Sm5Ni7 cuboctahedra, and faces with eight equivalent Ni(4)Sm4Ni8 cuboctahedra. Both Ni(4)-Ni(2) bond lengths are 2.47 Å. Both Ni(4)-Ni(3) bond lengths are 2.46 Å. In the seventh Ni site, Ni(4) is bonded to four Sm(1,1); two equivalent Ni(2); two equivalent Ni(3); and four equivalent Ni(4) atoms to form NiSm4Ni8 cuboctahedra that share corners with four equivalent Ni(4)Sm4Ni8 cuboctahedra, corners with twelve equivalent Ni(5)Sm5Ni7 cuboctahedra, edges with two equivalent Ni(4)Sm4Ni8 cuboctahedra, edges with eight equivalent Ni(5)Sm5Ni7 cuboctahedra, faces with two equivalent Ni(5)Sm5Ni7 cuboctahedra, and faces with eight equivalent Ni(4)Sm4Ni8 cuboctahedra. All Ni(4)-Ni(4) bond lengths are 2.48 Å. In the eighth Ni site, Ni(5) is bonded to two equivalent Sm(1), three equivalent Sm(2), one Ni(1), one Ni(2), one Ni(3), and four equivalent Ni(5) atoms to form distorted NiSm5Ni7 cuboctahedra that share corners with two equivalent Ni(1)Sm6Ni6 cuboctahedra, corners with six equivalent Ni(4)Sm4Ni8 cuboctahedra, corners with nine equivalent Ni(5)Sm5Ni7 cuboctahedra, edges with four equivalent Ni(4)Sm4Ni8 cuboctahedra, edges with four equivalent Ni(5)Sm5Ni7 cuboctahedra,  a faceface with one Ni(4)Sm4Ni8 cuboctahedra, faces with three equivalent Ni(1)Sm6Ni6 cuboctahedra, and faces with ten equivalent Ni(5)Sm5Ni7 cuboctahedra. There are two shorter (2.47 Å) and two longer (2.48 Å) Ni(5)-Ni(5) bond lengths.