Sm5Bi3 crystallizes in the orthorhombic Pnma space group. There are four inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 5-coordinate geometry to two equivalent Bi(2) and three equivalent Bi(1) atoms. In the second Sm site, Sm(2) is bonded to one Bi(2) and four equivalent Bi(1) atoms to form distorted edge-sharing SmBi5 square pyramids. In the third Sm site, Sm(3) is bonded in a 6-coordinate geometry to two equivalent Bi(2) and four equivalent Bi(1) atoms. In the fourth Sm site, Sm(4) is bonded in a 5-coordinate geometry to one Bi(2) and four equivalent Bi(1) atoms. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a 9-coordinate geometry to two equivalent Sm(2), two equivalent Sm(3), two equivalent Sm(4), and three equivalent Sm(1) atoms. In the second Bi site, Bi(2) is bonded in a 8-coordinate geometry to one Sm(2), one Sm(4), two equivalent Sm(3), and four equivalent Sm(1) atoms.
Sm5Bi3 crystallizes in the orthorhombic Pnma space group. There are four inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 5-coordinate geometry to two equivalent Bi(2) and three equivalent Bi(1) atoms. There is one shorter (3.16 Å) and one longer (3.26 Å) Sm(1)-Bi(2) bond length. There are a spread of Sm(1)-Bi(1) bond distances ranging from 3.43-3.63 Å. In the second Sm site, Sm(2) is bonded to one Bi(2) and four equivalent Bi(1) atoms to form distorted edge-sharing SmBi5 square pyramids. The Sm(2)-Bi(2) bond length is 3.25 Å. There are two shorter (3.29 Å) and two longer (3.34 Å) Sm(2)-Bi(1) bond lengths. In the third Sm site, Sm(3) is bonded in a 6-coordinate geometry to two equivalent Bi(2) and four equivalent Bi(1) atoms. There is one shorter (3.19 Å) and one longer (3.67 Å) Sm(3)-Bi(2) bond length. There are two shorter (3.30 Å) and two longer (3.44 Å) Sm(3)-Bi(1) bond lengths. In the fourth Sm site, Sm(4) is bonded in a 5-coordinate geometry to one Bi(2) and four equivalent Bi(1) atoms. The Sm(4)-Bi(2) bond length is 3.13 Å. There are two shorter (3.35 Å) and two longer (3.44 Å) Sm(4)-Bi(1) bond lengths. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a 9-coordinate geometry to two equivalent Sm(2), two equivalent Sm(3), two equivalent Sm(4), and three equivalent Sm(1) atoms. In the second Bi site, Bi(2) is bonded in a 8-coordinate geometry to one Sm(2), one Sm(4), two equivalent Sm(3), and four equivalent Sm(1) atoms.