SmNi9Si2 crystallizes in the tetragonal I4_1/amd space group. Sm(1) is bonded in a 18-coordinate geometry to two equivalent Ni(1) and sixteen equivalent Ni(2) atoms. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 14-coordinate geometry to two equivalent Sm(1), eight equivalent Ni(2), and four equivalent Si(1) atoms. In the second Ni site, Ni(2) is bonded to two equivalent Sm(1), one Ni(1), seven equivalent Ni(2), and two equivalent Si(1) atoms to form a mixture of distorted edge, corner, and face-sharing NiSm2Si2Ni8 cuboctahedra. Si(1) is bonded in a 10-coordinate geometry to two equivalent Ni(1) and eight equivalent Ni(2) atoms.
SmNi9Si2 crystallizes in the tetragonal I4_1/amd space group. Sm(1) is bonded in a 18-coordinate geometry to two equivalent Ni(1) and sixteen equivalent Ni(2) atoms. Both Sm(1)-Ni(1) bond lengths are 3.09 Å. There are eight shorter (3.03 Å) and eight longer (3.17 Å) Sm(1)-Ni(2) bond lengths. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 14-coordinate geometry to two equivalent Sm(1), eight equivalent Ni(2), and four equivalent Si(1) atoms. All Ni(1)-Ni(2) bond lengths are 2.61 Å. All Ni(1)-Si(1) bond lengths are 2.57 Å. In the second Ni site, Ni(2) is bonded to two equivalent Sm(1), one Ni(1), seven equivalent Ni(2), and two equivalent Si(1) atoms to form a mixture of distorted edge, corner, and face-sharing NiSm2Si2Ni8 cuboctahedra. There are a spread of Ni(2)-Ni(2) bond distances ranging from 2.41-2.58 Å. There is one shorter (2.33 Å) and one longer (2.37 Å) Ni(2)-Si(1) bond length. Si(1) is bonded in a 10-coordinate geometry to two equivalent Ni(1) and eight equivalent Ni(2) atoms.