Fe3Ni3Si2 is alpha La-derived structured and crystallizes in the orthorhombic Pmmm space group. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent Fe(2), two equivalent Ni(1), two equivalent Ni(2), two equivalent Ni(3), and four equivalent Si(1) atoms to form FeFe2Si4Ni6 cuboctahedra that share corners with twelve equivalent Fe(1)Fe2Si4Ni6 cuboctahedra, edges with four equivalent Fe(2)Fe4Si4Ni4 cuboctahedra, edges with four equivalent Ni(1)Fe4Si4Ni4 cuboctahedra, edges with four equivalent Ni(3)Fe4Si4Ni4 cuboctahedra, edges with four equivalent Ni(2)Fe8Si4 cuboctahedra, edges with eight equivalent Si(1)Fe6Ni6 cuboctahedra, faces with two equivalent Fe(2)Fe4Si4Ni4 cuboctahedra, faces with two equivalent Ni(1)Fe4Si4Ni4 cuboctahedra, faces with two equivalent Ni(3)Fe4Si4Ni4 cuboctahedra, faces with two equivalent Ni(2)Fe8Si4 cuboctahedra, faces with four equivalent Si(1)Fe6Ni6 cuboctahedra, and faces with six equivalent Fe(1)Fe2Si4Ni6 cuboctahedra. In the second Fe site, Fe(2) is bonded to four equivalent Fe(1), four equivalent Ni(2), and four equivalent Si(1) atoms to form FeFe4Si4Ni4 cuboctahedra that share corners with four equivalent Fe(2)Fe4Si4Ni4 cuboctahedra, corners with eight equivalent Ni(1)Fe4Si4Ni4 cuboctahedra, edges with eight equivalent Fe(1)Fe2Si4Ni6 cuboctahedra, edges with eight equivalent Ni(3)Fe4Si4Ni4 cuboctahedra, edges with eight equivalent Si(1)Fe6Ni6 cuboctahedra, faces with two equivalent Ni(1)Fe4Si4Ni4 cuboctahedra, faces with four equivalent Fe(1)Fe2Si4Ni6 cuboctahedra, faces with four equivalent Fe(2)Fe4Si4Ni4 cuboctahedra, faces with four equivalent Ni(2)Fe8Si4 cuboctahedra, and faces with four equivalent Si(1)Fe6Ni6 cuboctahedra. There are three inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to four equivalent Fe(1), four equivalent Ni(3), and four equivalent Si(1) atoms to form NiFe4Si4Ni4 cuboctahedra that share corners with four equivalent Ni(1)Fe4Si4Ni4 cuboctahedra, corners with eight equivalent Fe(2)Fe4Si4Ni4 cuboctahedra, edges with eight equivalent Fe(1)Fe2Si4Ni6 cuboctahedra, edges with eight equivalent Ni(2)Fe8Si4 cuboctahedra, edges with eight equivalent Si(1)Fe6Ni6 cuboctahedra, faces with two equivalent Fe(2)Fe4Si4Ni4 cuboctahedra, faces with four equivalent Fe(1)Fe2Si4Ni6 cuboctahedra, faces with four equivalent Ni(1)Fe4Si4Ni4 cuboctahedra, faces with four equivalent Ni(3)Fe4Si4Ni4 cuboctahedra, and faces with four equivalent Si(1)Fe6Ni6 cuboctahedra. In the second Ni site, Ni(2) is bonded to four equivalent Fe(1), four equivalent Fe(2), and four equivalent Si(1) atoms to form NiFe8Si4 cuboctahedra that share corners with four equivalent Ni(2)Fe8Si4 cuboctahedra, corners with eight equivalent Ni(3)Fe4Si4Ni4 cuboctahedra, edges with eight equivalent Fe(1)Fe2Si4Ni6 cuboctahedra, edges with eight equivalent Ni(1)Fe4Si4Ni4 cuboctahedra, edges with eight equivalent Si(1)Fe6Ni6 cuboctahedra, faces with two equivalent Ni(3)Fe4Si4Ni4 cuboctahedra, faces with four equivalent Fe(1)Fe2Si4Ni6 cuboctahedra, faces with four equivalent Fe(2)Fe4Si4Ni4 cuboctahedra, faces with four equivalent Ni(2)Fe8Si4 cuboctahedra, and faces with four equivalent Si(1)Fe6Ni6 cuboctahedra. In the third Ni site, Ni(3) is bonded to four equivalent Fe(1), four equivalent Ni(1), and four equivalent Si(1) atoms to form NiFe4Si4Ni4 cuboctahedra that share corners with four equivalent Ni(3)Fe4Si4Ni4 cuboctahedra, corners with eight equivalent Ni(2)Fe8Si4 cuboctahedra, edges with eight equivalent Fe(1)Fe2Si4Ni6 cuboctahedra, edges with eight equivalent Fe(2)Fe4Si4Ni4 cuboctahedra, edges with eight equivalent Si(1)Fe6Ni6 cuboctahedra, faces with two equivalent Ni(2)Fe8Si4 cuboctahedra, faces with four equivalent Fe(1)Fe2Si4Ni6 cuboctahedra, faces with four equivalent Ni(1)Fe4Si4Ni4 cuboctahedra, faces with four equivalent Ni(3)Fe4Si4Ni4 cuboctahedra, and faces with four equivalent Si(1)Fe6Ni6 cuboctahedra. Si(1) is bonded to two equivalent Fe(2), four equivalent Fe(1), two equivalent Ni(1), two equivalent Ni(2), and two equivalent Ni(3) atoms to form SiFe6Ni6 cuboctahedra that share corners with twelve equivalent Si(1)Fe6Ni6 cuboctahedra, edges with four equivalent Fe(2)Fe4Si4Ni4 cuboctahedra, edges with four equivalent Ni(1)Fe4Si4Ni4 cuboctahedra, edges with four equivalent Ni(3)Fe4Si4Ni4 cuboctahedra, edges with four equivalent Ni(2)Fe8Si4 cuboctahedra, edges with eight equivalent Fe(1)Fe2Si4Ni6 cuboctahedra, faces with two equivalent Fe(2)Fe4Si4Ni4 cuboctahedra, faces with two equivalent Ni(1)Fe4Si4Ni4 cuboctahedra, faces with two equivalent Ni(3)Fe4Si4Ni4 cuboctahedra, faces with two equivalent Ni(2)Fe8Si4 cuboctahedra, faces with four equivalent Fe(1)Fe2Si4Ni6 cuboctahedra, and faces with six equivalent Si(1)Fe6Ni6 cuboctahedra.
Fe3Ni3Si2 is alpha La-derived structured and crystallizes in the orthorhombic Pmmm space group. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent Fe(2), two equivalent Ni(1), two equivalent Ni(2), two equivalent Ni(3), and four equivalent Si(1) atoms to form FeFe2Si4Ni6 cuboctahedra that share corners with twelve equivalent Fe(1)Fe2Si4Ni6 cuboctahedra, edges with four equivalent Fe(2)Fe4Si4Ni4 cuboctahedra, edges with four equivalent Ni(1)Fe4Si4Ni4 cuboctahedra, edges with four equivalent Ni(3)Fe4Si4Ni4 cuboctahedra, edges with four equivalent Ni(2)Fe8Si4 cuboctahedra, edges with eight equivalent Si(1)Fe6Ni6 cuboctahedra, faces with two equivalent Fe(2)Fe4Si4Ni4 cuboctahedra, faces with two equivalent Ni(1)Fe4Si4Ni4 cuboctahedra, faces with two equivalent Ni(3)Fe4Si4Ni4 cuboctahedra, faces with two equivalent Ni(2)Fe8Si4 cuboctahedra, faces with four equivalent Si(1)Fe6Ni6 cuboctahedra, and faces with six equivalent Fe(1)Fe2Si4Ni6 cuboctahedra. Both Fe(1)-Fe(2) bond lengths are 2.45 Å. Both Fe(1)-Ni(1) bond lengths are 2.49 Å. Both Fe(1)-Ni(2) bond lengths are 2.51 Å. Both Fe(1)-Ni(3) bond lengths are 2.54 Å. All Fe(1)-Si(1) bond lengths are 2.51 Å. In the second Fe site, Fe(2) is bonded to four equivalent Fe(1), four equivalent Ni(2), and four equivalent Si(1) atoms to form FeFe4Si4Ni4 cuboctahedra that share corners with four equivalent Fe(2)Fe4Si4Ni4 cuboctahedra, corners with eight equivalent Ni(1)Fe4Si4Ni4 cuboctahedra, edges with eight equivalent Fe(1)Fe2Si4Ni6 cuboctahedra, edges with eight equivalent Ni(3)Fe4Si4Ni4 cuboctahedra, edges with eight equivalent Si(1)Fe6Ni6 cuboctahedra, faces with two equivalent Ni(1)Fe4Si4Ni4 cuboctahedra, faces with four equivalent Fe(1)Fe2Si4Ni6 cuboctahedra, faces with four equivalent Fe(2)Fe4Si4Ni4 cuboctahedra, faces with four equivalent Ni(2)Fe8Si4 cuboctahedra, and faces with four equivalent Si(1)Fe6Ni6 cuboctahedra. All Fe(2)-Ni(2) bond lengths are 2.51 Å. All Fe(2)-Si(1) bond lengths are 2.54 Å. There are three inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to four equivalent Fe(1), four equivalent Ni(3), and four equivalent Si(1) atoms to form NiFe4Si4Ni4 cuboctahedra that share corners with four equivalent Ni(1)Fe4Si4Ni4 cuboctahedra, corners with eight equivalent Fe(2)Fe4Si4Ni4 cuboctahedra, edges with eight equivalent Fe(1)Fe2Si4Ni6 cuboctahedra, edges with eight equivalent Ni(2)Fe8Si4 cuboctahedra, edges with eight equivalent Si(1)Fe6Ni6 cuboctahedra, faces with two equivalent Fe(2)Fe4Si4Ni4 cuboctahedra, faces with four equivalent Fe(1)Fe2Si4Ni6 cuboctahedra, faces with four equivalent Ni(1)Fe4Si4Ni4 cuboctahedra, faces with four equivalent Ni(3)Fe4Si4Ni4 cuboctahedra, and faces with four equivalent Si(1)Fe6Ni6 cuboctahedra. All Ni(1)-Ni(3) bond lengths are 2.51 Å. All Ni(1)-Si(1) bond lengths are 2.51 Å. In the second Ni site, Ni(2) is bonded to four equivalent Fe(1), four equivalent Fe(2), and four equivalent Si(1) atoms to form NiFe8Si4 cuboctahedra that share corners with four equivalent Ni(2)Fe8Si4 cuboctahedra, corners with eight equivalent Ni(3)Fe4Si4Ni4 cuboctahedra, edges with eight equivalent Fe(1)Fe2Si4Ni6 cuboctahedra, edges with eight equivalent Ni(1)Fe4Si4Ni4 cuboctahedra, edges with eight equivalent Si(1)Fe6Ni6 cuboctahedra, faces with two equivalent Ni(3)Fe4Si4Ni4 cuboctahedra, faces with four equivalent Fe(1)Fe2Si4Ni6 cuboctahedra, faces with four equivalent Fe(2)Fe4Si4Ni4 cuboctahedra, faces with four equivalent Ni(2)Fe8Si4 cuboctahedra, and faces with four equivalent Si(1)Fe6Ni6 cuboctahedra. All Ni(2)-Si(1) bond lengths are 2.48 Å. In the third Ni site, Ni(3) is bonded to four equivalent Fe(1), four equivalent Ni(1), and four equivalent Si(1) atoms to form NiFe4Si4Ni4 cuboctahedra that share corners with four equivalent Ni(3)Fe4Si4Ni4 cuboctahedra, corners with eight equivalent Ni(2)Fe8Si4 cuboctahedra, edges with eight equivalent Fe(1)Fe2Si4Ni6 cuboctahedra, edges with eight equivalent Fe(2)Fe4Si4Ni4 cuboctahedra, edges with eight equivalent Si(1)Fe6Ni6 cuboctahedra, faces with two equivalent Ni(2)Fe8Si4 cuboctahedra, faces with four equivalent Fe(1)Fe2Si4Ni6 cuboctahedra, faces with four equivalent Ni(1)Fe4Si4Ni4 cuboctahedra, faces with four equivalent Ni(3)Fe4Si4Ni4 cuboctahedra, and faces with four equivalent Si(1)Fe6Ni6 cuboctahedra. All Ni(3)-Si(1) bond lengths are 2.46 Å. Si(1) is bonded to two equivalent Fe(2), four equivalent Fe(1), two equivalent Ni(1), two equivalent Ni(2), and two equivalent Ni(3) atoms to form SiFe6Ni6 cuboctahedra that share corners with twelve equivalent Si(1)Fe6Ni6 cuboctahedra, edges with four equivalent Fe(2)Fe4Si4Ni4 cuboctahedra, edges with four equivalent Ni(1)Fe4Si4Ni4 cuboctahedra, edges with four equivalent Ni(3)Fe4Si4Ni4 cuboctahedra, edges with four equivalent Ni(2)Fe8Si4 cuboctahedra, edges with eight equivalent Fe(1)Fe2Si4Ni6 cuboctahedra, faces with two equivalent Fe(2)Fe4Si4Ni4 cuboctahedra, faces with two equivalent Ni(1)Fe4Si4Ni4 cuboctahedra, faces with two equivalent Ni(3)Fe4Si4Ni4 cuboctahedra, faces with two equivalent Ni(2)Fe8Si4 cuboctahedra, faces with four equivalent Fe(1)Fe2Si4Ni6 cuboctahedra, and faces with six equivalent Si(1)Fe6Ni6 cuboctahedra.