Nd4Si7 crystallizes in the orthorhombic Pmm2 space group. There are four inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a 6-coordinate geometry to two equivalent Nd(1), one Si(1), one Si(5), and two equivalent Si(3) atoms. In the second Nd site, Nd(2) is bonded in a 3-coordinate geometry to one Si(1), one Si(2), two equivalent Si(4), and two equivalent Si(7) atoms. In the third Nd site, Nd(3) is bonded in a 4-coordinate geometry to one Si(3), one Si(7), and two equivalent Si(1) atoms. In the fourth Nd site, Nd(4) is bonded in a distorted square co-planar geometry to one Si(4), one Si(6), two equivalent Si(2), and two equivalent Si(5) atoms. There are seven inequivalent Si sites. In the first Si site, Si(1) is bonded in a 4-coordinate geometry to one Nd(1), one Nd(2), and two equivalent Nd(3) atoms. In the second Si site, Si(2) is bonded in a square co-planar geometry to one Nd(2), two equivalent Nd(4), and one Si(5) atom. In the third Si site, Si(3) is bonded in a distorted square co-planar geometry to one Nd(3), two equivalent Nd(1), and one Si(6) atom. In the fourth Si site, Si(4) is bonded in a square co-planar geometry to one Nd(4), two equivalent Nd(2), and one Si(7) atom. In the fifth Si site, Si(5) is bonded in a distorted linear geometry to one Nd(1), two equivalent Nd(4), one Si(2), and two equivalent Si(6) atoms. In the sixth Si site, Si(6) is bonded in a distorted linear geometry to one Nd(4), one Si(3), and two equivalent Si(5) atoms. In the seventh Si site, Si(7) is bonded in a 4-coordinate geometry to one Nd(3), two equivalent Nd(2), and one Si(4) atom.
Nd4Si7 crystallizes in the orthorhombic Pmm2 space group. There are four inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a 6-coordinate geometry to two equivalent Nd(1), one Si(1), one Si(5), and two equivalent Si(3) atoms. Both Nd(1)-Nd(1) bond lengths are 3.27 Å. The Nd(1)-Si(1) bond length is 3.27 Å. The Nd(1)-Si(5) bond length is 3.58 Å. Both Nd(1)-Si(3) bond lengths are 2.85 Å. In the second Nd site, Nd(2) is bonded in a 3-coordinate geometry to one Si(1), one Si(2), two equivalent Si(4), and two equivalent Si(7) atoms. The Nd(2)-Si(1) bond length is 3.68 Å. The Nd(2)-Si(2) bond length is 2.95 Å. Both Nd(2)-Si(4) bond lengths are 2.82 Å. Both Nd(2)-Si(7) bond lengths are 3.35 Å. In the third Nd site, Nd(3) is bonded in a 4-coordinate geometry to one Si(3), one Si(7), and two equivalent Si(1) atoms. The Nd(3)-Si(3) bond length is 2.86 Å. The Nd(3)-Si(7) bond length is 2.79 Å. Both Nd(3)-Si(1) bond lengths are 2.95 Å. In the fourth Nd site, Nd(4) is bonded in a distorted square co-planar geometry to one Si(4), one Si(6), two equivalent Si(2), and two equivalent Si(5) atoms. The Nd(4)-Si(4) bond length is 2.85 Å. The Nd(4)-Si(6) bond length is 2.86 Å. Both Nd(4)-Si(2) bond lengths are 2.81 Å. Both Nd(4)-Si(5) bond lengths are 3.46 Å. There are seven inequivalent Si sites. In the first Si site, Si(1) is bonded in a 4-coordinate geometry to one Nd(1), one Nd(2), and two equivalent Nd(3) atoms. In the second Si site, Si(2) is bonded in a square co-planar geometry to one Nd(2), two equivalent Nd(4), and one Si(5) atom. The Si(2)-Si(5) bond length is 2.33 Å. In the third Si site, Si(3) is bonded in a distorted square co-planar geometry to one Nd(3), two equivalent Nd(1), and one Si(6) atom. The Si(3)-Si(6) bond length is 2.21 Å. In the fourth Si site, Si(4) is bonded in a square co-planar geometry to one Nd(4), two equivalent Nd(2), and one Si(7) atom. The Si(4)-Si(7) bond length is 2.24 Å. In the fifth Si site, Si(5) is bonded in a distorted linear geometry to one Nd(1), two equivalent Nd(4), one Si(2), and two equivalent Si(6) atoms. Both Si(5)-Si(6) bond lengths are 2.91 Å. In the sixth Si site, Si(6) is bonded in a distorted linear geometry to one Nd(4), one Si(3), and two equivalent Si(5) atoms. In the seventh Si site, Si(7) is bonded in a 4-coordinate geometry to one Nd(3), two equivalent Nd(2), and one Si(4) atom.