Sm2Fe14Ga3C2 crystallizes in the monoclinic C2/m space group. Sm(1) is bonded in a distorted bent 120 degrees geometry to one Fe(1), two equivalent Fe(4), three equivalent Fe(2), one Ga(1), two equivalent Ga(2), and two equivalent C(1) atoms. There are five inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 14-coordinate geometry to one Sm(1), one Fe(1), one Fe(2), two equivalent Fe(3), two equivalent Fe(4), four equivalent Fe(5), one Ga(1), and two equivalent Ga(2) atoms. In the second Fe site, Fe(2) is bonded to three equivalent Sm(1), one Fe(1), two equivalent Fe(3), two equivalent Fe(4), two equivalent Fe(5), and two equivalent Ga(2) atoms to form FeSm3Ga2Fe7 cuboctahedra that share corners with two equivalent Ga(2)Sm2Fe10 cuboctahedra, corners with three equivalent Ga(1)Sm2Fe10 cuboctahedra, corners with four equivalent Fe(2)Sm3Ga2Fe7 cuboctahedra, corners with four equivalent C(1)Sm2Fe4 octahedra,  an edgeedge with one Fe(2)Sm3Ga2Fe7 cuboctahedra,  an edgeedge with one Ga(1)Sm2Fe10 cuboctahedra, edges with two equivalent Ga(2)Sm2Fe10 cuboctahedra,  a faceface with one Fe(2)Sm3Ga2Fe7 cuboctahedra,  a faceface with one Ga(1)Sm2Fe10 cuboctahedra, faces with two equivalent Ga(2)Sm2Fe10 cuboctahedra, and faces with two equivalent C(1)Sm2Fe4 octahedra. The corner-sharing octahedral tilt angles range from 63-69°. In the third Fe site, Fe(3) is bonded in a single-bond geometry to one Fe(1), one Fe(2), one Fe(4), one Ga(1), one Ga(2), and one C(1) atom. In the fourth Fe site, Fe(4) is bonded in a 12-coordinate geometry to two equivalent Sm(1), two equivalent Fe(1), two equivalent Fe(2), two equivalent Fe(3), two equivalent Fe(5), and two equivalent Ga(2) atoms. In the fifth Fe site, Fe(5) is bonded in a single-bond geometry to one Fe(2), one Fe(4), two equivalent Fe(1), one Ga(1), one Ga(2), and one C(1) atom. There are two inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to two equivalent Sm(1), two equivalent Fe(1), four equivalent Fe(3), and four equivalent Fe(5) atoms to form distorted GaSm2Fe10 cuboctahedra that share corners with four equivalent Ga(2)Sm2Fe10 cuboctahedra, corners with six equivalent Fe(2)Sm3Ga2Fe7 cuboctahedra, edges with two equivalent Fe(2)Sm3Ga2Fe7 cuboctahedra, faces with two equivalent Fe(2)Sm3Ga2Fe7 cuboctahedra, faces with four equivalent Ga(2)Sm2Fe10 cuboctahedra, and faces with four equivalent C(1)Sm2Fe4 octahedra. In the second Ga site, Ga(2) is bonded to two equivalent Sm(1), two equivalent Fe(1), two equivalent Fe(2), two equivalent Fe(3), two equivalent Fe(4), and two equivalent Fe(5) atoms to form distorted GaSm2Fe10 cuboctahedra that share corners with two equivalent Fe(2)Sm3Ga2Fe7 cuboctahedra, corners with two equivalent Ga(1)Sm2Fe10 cuboctahedra, corners with two equivalent Ga(2)Sm2Fe10 cuboctahedra, corners with two equivalent C(1)Sm2Fe4 octahedra, edges with two equivalent Fe(2)Sm3Ga2Fe7 cuboctahedra, faces with two equivalent Fe(2)Sm3Ga2Fe7 cuboctahedra, faces with two equivalent Ga(1)Sm2Fe10 cuboctahedra, faces with two equivalent Ga(2)Sm2Fe10 cuboctahedra, and faces with two equivalent C(1)Sm2Fe4 octahedra. The corner-sharing octahedral tilt angles are 45°. C(1) is bonded to two equivalent Sm(1), two equivalent Fe(3), and two equivalent Fe(5) atoms to form CSm2Fe4 octahedra that share corners with two equivalent Ga(2)Sm2Fe10 cuboctahedra, corners with four equivalent Fe(2)Sm3Ga2Fe7 cuboctahedra, corners with two equivalent C(1)Sm2Fe4 octahedra, faces with two equivalent Fe(2)Sm3Ga2Fe7 cuboctahedra, faces with two equivalent Ga(1)Sm2Fe10 cuboctahedra, and faces with two equivalent Ga(2)Sm2Fe10 cuboctahedra. The corner-sharing octahedral tilt angles are 63°.
Sm2Fe14Ga3C2 crystallizes in the monoclinic C2/m space group. Sm(1) is bonded in a distorted bent 120 degrees geometry to one Fe(1), two equivalent Fe(4), three equivalent Fe(2), one Ga(1), two equivalent Ga(2), and two equivalent C(1) atoms. The Sm(1)-Fe(1) bond length is 3.14 Å. Both Sm(1)-Fe(4) bond lengths are 3.07 Å. There are a spread of Sm(1)-Fe(2) bond distances ranging from 3.06-3.33 Å. The Sm(1)-Ga(1) bond length is 3.40 Å. Both Sm(1)-Ga(2) bond lengths are 3.32 Å. Both Sm(1)-C(1) bond lengths are 2.54 Å. There are five inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 14-coordinate geometry to one Sm(1), one Fe(1), one Fe(2), two equivalent Fe(3), two equivalent Fe(4), four equivalent Fe(5), one Ga(1), and two equivalent Ga(2) atoms. The Fe(1)-Fe(1) bond length is 2.31 Å. The Fe(1)-Fe(2) bond length is 2.73 Å. Both Fe(1)-Fe(3) bond lengths are 2.69 Å. Both Fe(1)-Fe(4) bond lengths are 2.75 Å. There are two shorter (2.74 Å) and two longer (2.75 Å) Fe(1)-Fe(5) bond lengths. The Fe(1)-Ga(1) bond length is 2.66 Å. Both Fe(1)-Ga(2) bond lengths are 2.68 Å. In the second Fe site, Fe(2) is bonded to three equivalent Sm(1), one Fe(1), two equivalent Fe(3), two equivalent Fe(4), two equivalent Fe(5), and two equivalent Ga(2) atoms to form FeSm3Ga2Fe7 cuboctahedra that share corners with two equivalent Ga(2)Sm2Fe10 cuboctahedra, corners with three equivalent Ga(1)Sm2Fe10 cuboctahedra, corners with four equivalent Fe(2)Sm3Ga2Fe7 cuboctahedra, corners with four equivalent C(1)Sm2Fe4 octahedra,  an edgeedge with one Fe(2)Sm3Ga2Fe7 cuboctahedra,  an edgeedge with one Ga(1)Sm2Fe10 cuboctahedra, edges with two equivalent Ga(2)Sm2Fe10 cuboctahedra,  a faceface with one Fe(2)Sm3Ga2Fe7 cuboctahedra,  a faceface with one Ga(1)Sm2Fe10 cuboctahedra, faces with two equivalent Ga(2)Sm2Fe10 cuboctahedra, and faces with two equivalent C(1)Sm2Fe4 octahedra. The corner-sharing octahedral tilt angles range from 63-69°. Both Fe(2)-Fe(3) bond lengths are 2.54 Å. Both Fe(2)-Fe(4) bond lengths are 2.66 Å. Both Fe(2)-Fe(5) bond lengths are 2.57 Å. Both Fe(2)-Ga(2) bond lengths are 2.50 Å. In the third Fe site, Fe(3) is bonded in a single-bond geometry to one Fe(1), one Fe(2), one Fe(4), one Ga(1), one Ga(2), and one C(1) atom. The Fe(3)-Fe(4) bond length is 2.58 Å. The Fe(3)-Ga(1) bond length is 2.51 Å. The Fe(3)-Ga(2) bond length is 2.50 Å. The Fe(3)-C(1) bond length is 1.91 Å. In the fourth Fe site, Fe(4) is bonded in a 12-coordinate geometry to two equivalent Sm(1), two equivalent Fe(1), two equivalent Fe(2), two equivalent Fe(3), two equivalent Fe(5), and two equivalent Ga(2) atoms. Both Fe(4)-Fe(5) bond lengths are 2.50 Å. Both Fe(4)-Ga(2) bond lengths are 2.46 Å. In the fifth Fe site, Fe(5) is bonded in a single-bond geometry to one Fe(2), one Fe(4), two equivalent Fe(1), one Ga(1), one Ga(2), and one C(1) atom. The Fe(5)-Ga(1) bond length is 2.44 Å. The Fe(5)-Ga(2) bond length is 2.44 Å. The Fe(5)-C(1) bond length is 1.86 Å. There are two inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to two equivalent Sm(1), two equivalent Fe(1), four equivalent Fe(3), and four equivalent Fe(5) atoms to form distorted GaSm2Fe10 cuboctahedra that share corners with four equivalent Ga(2)Sm2Fe10 cuboctahedra, corners with six equivalent Fe(2)Sm3Ga2Fe7 cuboctahedra, edges with two equivalent Fe(2)Sm3Ga2Fe7 cuboctahedra, faces with two equivalent Fe(2)Sm3Ga2Fe7 cuboctahedra, faces with four equivalent Ga(2)Sm2Fe10 cuboctahedra, and faces with four equivalent C(1)Sm2Fe4 octahedra. In the second Ga site, Ga(2) is bonded to two equivalent Sm(1), two equivalent Fe(1), two equivalent Fe(2), two equivalent Fe(3), two equivalent Fe(4), and two equivalent Fe(5) atoms to form distorted GaSm2Fe10 cuboctahedra that share corners with two equivalent Fe(2)Sm3Ga2Fe7 cuboctahedra, corners with two equivalent Ga(1)Sm2Fe10 cuboctahedra, corners with two equivalent Ga(2)Sm2Fe10 cuboctahedra, corners with two equivalent C(1)Sm2Fe4 octahedra, edges with two equivalent Fe(2)Sm3Ga2Fe7 cuboctahedra, faces with two equivalent Fe(2)Sm3Ga2Fe7 cuboctahedra, faces with two equivalent Ga(1)Sm2Fe10 cuboctahedra, faces with two equivalent Ga(2)Sm2Fe10 cuboctahedra, and faces with two equivalent C(1)Sm2Fe4 octahedra. The corner-sharing octahedral tilt angles are 45°. C(1) is bonded to two equivalent Sm(1), two equivalent Fe(3), and two equivalent Fe(5) atoms to form CSm2Fe4 octahedra that share corners with two equivalent Ga(2)Sm2Fe10 cuboctahedra, corners with four equivalent Fe(2)Sm3Ga2Fe7 cuboctahedra, corners with two equivalent C(1)Sm2Fe4 octahedra, faces with two equivalent Fe(2)Sm3Ga2Fe7 cuboctahedra, faces with two equivalent Ga(1)Sm2Fe10 cuboctahedra, and faces with two equivalent Ga(2)Sm2Fe10 cuboctahedra. The corner-sharing octahedral tilt angles are 63°.