Nd3NiSi3 crystallizes in the orthorhombic Imm2 space group. There are three inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a 7-coordinate geometry to one Si(1), two equivalent Si(3), and four equivalent Si(2) atoms. In the second Nd site, Nd(2) is bonded in a 7-coordinate geometry to two equivalent Ni(1), one Si(2), and four equivalent Si(1) atoms. In the third Nd site, Nd(3) is bonded to four equivalent Ni(1), two equivalent Si(1), two equivalent Si(2), and four equivalent Si(3) atoms to form a mixture of edge and face-sharing NdSi8Ni4 cuboctahedra. Ni(1) is bonded in a 9-coordinate geometry to two equivalent Nd(2), four equivalent Nd(3), one Si(3), and two equivalent Si(1) atoms. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to one Nd(1), two equivalent Nd(3), four equivalent Nd(2), and two equivalent Ni(1) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to one Nd(2), two equivalent Nd(3), four equivalent Nd(1), and two equivalent Si(3) atoms. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to two equivalent Nd(1), four equivalent Nd(3), one Ni(1), and two equivalent Si(2) atoms.
Nd3NiSi3 crystallizes in the orthorhombic Imm2 space group. There are three inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a 7-coordinate geometry to one Si(1), two equivalent Si(3), and four equivalent Si(2) atoms. The Nd(1)-Si(1) bond length is 3.22 Å. Both Nd(1)-Si(3) bond lengths are 3.13 Å. All Nd(1)-Si(2) bond lengths are 3.06 Å. In the second Nd site, Nd(2) is bonded in a 7-coordinate geometry to two equivalent Ni(1), one Si(2), and four equivalent Si(1) atoms. Both Nd(2)-Ni(1) bond lengths are 3.00 Å. The Nd(2)-Si(2) bond length is 3.19 Å. All Nd(2)-Si(1) bond lengths are 3.07 Å. In the third Nd site, Nd(3) is bonded to four equivalent Ni(1), two equivalent Si(1), two equivalent Si(2), and four equivalent Si(3) atoms to form a mixture of edge and face-sharing NdSi8Ni4 cuboctahedra. All Nd(3)-Ni(1) bond lengths are 3.19 Å. Both Nd(3)-Si(1) bond lengths are 3.26 Å. Both Nd(3)-Si(2) bond lengths are 3.34 Å. All Nd(3)-Si(3) bond lengths are 3.15 Å. Ni(1) is bonded in a 9-coordinate geometry to two equivalent Nd(2), four equivalent Nd(3), one Si(3), and two equivalent Si(1) atoms. The Ni(1)-Si(3) bond length is 2.27 Å. Both Ni(1)-Si(1) bond lengths are 2.37 Å. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to one Nd(1), two equivalent Nd(3), four equivalent Nd(2), and two equivalent Ni(1) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to one Nd(2), two equivalent Nd(3), four equivalent Nd(1), and two equivalent Si(3) atoms. Both Si(2)-Si(3) bond lengths are 2.49 Å. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to two equivalent Nd(1), four equivalent Nd(3), one Ni(1), and two equivalent Si(2) atoms.