La3Ni3Si7 crystallizes in the orthorhombic Amm2 space group. There are three inequivalent La sites. In the first La site, La(1) is bonded in a 16-coordinate geometry to four equivalent Ni(3), two equivalent Si(1), two equivalent Si(2), two equivalent Si(5), two equivalent Si(6), and four equivalent Si(7) atoms. In the second La site, La(2) is bonded in a 14-coordinate geometry to four equivalent Ni(2), two equivalent Si(1), two equivalent Si(3), two equivalent Si(6), and four equivalent Si(4) atoms. In the third La site, La(3) is bonded in a 14-coordinate geometry to four equivalent Ni(1), two equivalent Si(2), two equivalent Si(4), two equivalent Si(5), and four equivalent Si(3) atoms. There are three inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 9-coordinate geometry to four equivalent La(3), one Si(3), two equivalent Si(2), and two equivalent Si(5) atoms. In the second Ni site, Ni(2) is bonded in a 5-coordinate geometry to four equivalent La(2), one Si(4), two equivalent Si(1), and two equivalent Si(6) atoms. In the third Ni site, Ni(3) is bonded in a 9-coordinate geometry to four equivalent La(1), one Si(7), 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 8-coordinate geometry to two equivalent La(1), two equivalent La(2), two equivalent Ni(2), and two equivalent Si(7) atoms. In the second Si site, Si(2) is bonded in a 8-coordinate geometry to two equivalent La(1), two equivalent La(3), two equivalent Ni(1), and two equivalent Ni(3) atoms. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to two equivalent La(2), four equivalent La(3), one Ni(1), and two equivalent Si(4) atoms. In the fourth Si site, Si(4) is bonded in a 9-coordinate geometry to two equivalent La(3), four equivalent La(2), one Ni(2), and two equivalent Si(3) atoms. In the fifth Si site, Si(5) is bonded in a 8-coordinate geometry to two equivalent La(1), two equivalent La(3), two equivalent Ni(1), and two equivalent Ni(3) atoms. In the sixth Si site, Si(6) is bonded in a 8-coordinate geometry to two equivalent La(1), two equivalent La(2), two equivalent Ni(2), and two equivalent Si(7) atoms. In the seventh Si site, Si(7) is bonded in a 9-coordinate geometry to four equivalent La(1), one Ni(3), two equivalent Si(1), and two equivalent Si(6) atoms.
La3Ni3Si7 crystallizes in the orthorhombic Amm2 space group. There are three inequivalent La sites. In the first La site, La(1) is bonded in a 16-coordinate geometry to four equivalent Ni(3), two equivalent Si(1), two equivalent Si(2), two equivalent Si(5), two equivalent Si(6), and four equivalent Si(7) atoms. All La(1)-Ni(3) bond lengths are 3.22 Å. Both La(1)-Si(1) bond lengths are 3.19 Å. Both La(1)-Si(2) bond lengths are 3.17 Å. Both La(1)-Si(5) bond lengths are 3.20 Å. Both La(1)-Si(6) bond lengths are 3.23 Å. All La(1)-Si(7) bond lengths are 3.11 Å. In the second La site, La(2) is bonded in a 14-coordinate geometry to four equivalent Ni(2), two equivalent Si(1), two equivalent Si(3), two equivalent Si(6), and four equivalent Si(4) atoms. All La(2)-Ni(2) bond lengths are 3.27 Å. Both La(2)-Si(1) bond lengths are 3.21 Å. Both La(2)-Si(3) bond lengths are 3.17 Å. Both La(2)-Si(6) bond lengths are 3.17 Å. All La(2)-Si(4) bond lengths are 3.12 Å. In the third La site, La(3) is bonded in a 14-coordinate geometry to four equivalent Ni(1), two equivalent Si(2), two equivalent Si(4), two equivalent Si(5), and four equivalent Si(3) atoms. All La(3)-Ni(1) bond lengths are 3.21 Å. Both La(3)-Si(2) bond lengths are 3.16 Å. Both La(3)-Si(4) bond lengths are 3.24 Å. Both La(3)-Si(5) bond lengths are 3.13 Å. All La(3)-Si(3) bond lengths are 3.15 Å. There are three inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 9-coordinate geometry to four equivalent La(3), one Si(3), two equivalent Si(2), and two equivalent Si(5) atoms. The Ni(1)-Si(3) bond length is 2.35 Å. Both Ni(1)-Si(2) bond lengths are 2.34 Å. Both Ni(1)-Si(5) bond lengths are 2.38 Å. In the second Ni site, Ni(2) is bonded in a 5-coordinate geometry to four equivalent La(2), one Si(4), two equivalent Si(1), and two equivalent Si(6) atoms. The Ni(2)-Si(4) bond length is 2.41 Å. Both Ni(2)-Si(1) bond lengths are 2.30 Å. Both Ni(2)-Si(6) bond lengths are 2.34 Å. In the third Ni site, Ni(3) is bonded in a 9-coordinate geometry to four equivalent La(1), one Si(7), two equivalent Si(2), and two equivalent Si(5) atoms. The Ni(3)-Si(7) bond length is 2.28 Å. Both Ni(3)-Si(2) bond lengths are 2.38 Å. Both Ni(3)-Si(5) bond lengths are 2.34 Å. There are seven inequivalent Si sites. In the first Si site, Si(1) is bonded in a 8-coordinate geometry to two equivalent La(1), two equivalent La(2), two equivalent Ni(2), and two equivalent Si(7) atoms. Both Si(1)-Si(7) bond lengths are 2.56 Å. In the second Si site, Si(2) is bonded in a 8-coordinate geometry to two equivalent La(1), two equivalent La(3), two equivalent Ni(1), and two equivalent Ni(3) atoms. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to two equivalent La(2), four equivalent La(3), one Ni(1), and two equivalent Si(4) atoms. Both Si(3)-Si(4) bond lengths are 2.47 Å. In the fourth Si site, Si(4) is bonded in a 9-coordinate geometry to two equivalent La(3), four equivalent La(2), one Ni(2), and two equivalent Si(3) atoms. In the fifth Si site, Si(5) is bonded in a 8-coordinate geometry to two equivalent La(1), two equivalent La(3), two equivalent Ni(1), and two equivalent Ni(3) atoms. In the sixth Si site, Si(6) is bonded in a 8-coordinate geometry to two equivalent La(1), two equivalent La(2), two equivalent Ni(2), and two equivalent Si(7) atoms. Both Si(6)-Si(7) bond lengths are 2.53 Å. In the seventh Si site, Si(7) is bonded in a 9-coordinate geometry to four equivalent La(1), one Ni(3), two equivalent Si(1), and two equivalent Si(6) atoms.