ZrFeSi2 crystallizes in the orthorhombic Cmce space group. There are three inequivalent Zr sites. In the first Zr site, Zr(1) is bonded in a 7-coordinate geometry to two equivalent Fe(1), two equivalent Fe(2), one Si(3), one Si(6), two equivalent Si(2), and three equivalent Si(5) atoms. In the second Zr site, Zr(2) is bonded in a 8-coordinate geometry to two equivalent Fe(2), one Si(3), two equivalent Si(1), two equivalent Si(2), and three equivalent Si(4) atoms. In the third Zr site, Zr(3) is bonded in a 12-coordinate geometry to two equivalent Fe(1), two equivalent Fe(3), one Si(3), one Si(5), two equivalent Si(1), two equivalent Si(2), and two equivalent Si(6) atoms. There are three inequivalent Fe sites. In the first Fe site, Fe(3) is bonded in a 6-coordinate geometry to two equivalent Zr(3), one Si(4), one Si(6), two equivalent Si(1), and two equivalent Si(2) atoms. In the second Fe site, Fe(1) is bonded to two equivalent Zr(1), two equivalent Zr(3), two equivalent Fe(1), two equivalent Si(3), two equivalent Si(5), and two equivalent Si(6) atoms to form a mixture of distorted face, corner, and edge-sharing FeZr4Fe2Si6 cuboctahedra. In the third Fe site, Fe(2) is bonded to two equivalent Zr(1), two equivalent Zr(2), two equivalent Fe(2), two equivalent Si(3), two equivalent Si(4), and two equivalent Si(5) atoms to form a mixture of distorted face, corner, and edge-sharing FeZr4Fe2Si6 cuboctahedra. There are six inequivalent Si sites. In the first Si site, Si(5) is bonded in a 8-coordinate geometry to one Zr(3), three equivalent Zr(1), two equivalent Fe(1), and two equivalent Fe(2) atoms. In the second Si site, Si(6) is bonded in a 7-coordinate geometry to one Zr(1), two equivalent Zr(3), one Fe(3), two equivalent Fe(1), and one Si(4) atom. In the third Si site, Si(4) is bonded in a 7-coordinate geometry to three equivalent Zr(2), one Fe(3), two equivalent Fe(2), and one Si(6) atom. In the fourth Si site, Si(1) is bonded in a 8-coordinate geometry to two equivalent Zr(2), two equivalent Zr(3), two equivalent Fe(3), and two equivalent Si(1) atoms. In the fifth Si site, Si(2) is bonded in a 10-coordinate geometry to two equivalent Zr(1), two equivalent Zr(2), two equivalent Zr(3), two equivalent Fe(3), and two equivalent Si(2) atoms. In the sixth Si site, Si(3) is bonded in a 7-coordinate geometry to one Zr(1), one Zr(2), one Zr(3), two equivalent Fe(1), and two equivalent Fe(2) atoms.
ZrFeSi2 crystallizes in the orthorhombic Cmce space group. There are three inequivalent Zr sites. In the first Zr site, Zr(1) is bonded in a 7-coordinate geometry to two equivalent Fe(1), two equivalent Fe(2), one Si(3), one Si(6), two equivalent Si(2), and three equivalent Si(5) atoms. Both Zr(1)-Fe(1) bond lengths are 3.04 Å. Both Zr(1)-Fe(2) bond lengths are 3.01 Å. The Zr(1)-Si(3) bond length is 2.69 Å. The Zr(1)-Si(6) bond length is 2.76 Å. Both Zr(1)-Si(2) bond lengths are 2.76 Å. There is one shorter (2.74 Å) and two longer (2.88 Å) Zr(1)-Si(5) bond lengths. In the second Zr site, Zr(2) is bonded in a 8-coordinate geometry to two equivalent Fe(2), one Si(3), two equivalent Si(1), two equivalent Si(2), and three equivalent Si(4) atoms. Both Zr(2)-Fe(2) bond lengths are 2.93 Å. The Zr(2)-Si(3) bond length is 2.72 Å. Both Zr(2)-Si(1) bond lengths are 2.87 Å. Both Zr(2)-Si(2) bond lengths are 2.79 Å. There is one shorter (2.76 Å) and two longer (2.80 Å) Zr(2)-Si(4) bond lengths. In the third Zr site, Zr(3) is bonded in a 12-coordinate geometry to two equivalent Fe(1), two equivalent Fe(3), one Si(3), one Si(5), two equivalent Si(1), two equivalent Si(2), and two equivalent Si(6) atoms. Both Zr(3)-Fe(1) bond lengths are 2.95 Å. Both Zr(3)-Fe(3) bond lengths are 3.07 Å. The Zr(3)-Si(3) bond length is 2.77 Å. The Zr(3)-Si(5) bond length is 2.80 Å. Both Zr(3)-Si(1) bond lengths are 2.90 Å. Both Zr(3)-Si(2) bond lengths are 2.81 Å. Both Zr(3)-Si(6) bond lengths are 2.80 Å. There are three inequivalent Fe sites. In the first Fe site, Fe(3) is bonded in a 6-coordinate geometry to two equivalent Zr(3), one Si(4), one Si(6), two equivalent Si(1), and two equivalent Si(2) atoms. The Fe(3)-Si(4) bond length is 2.46 Å. The Fe(3)-Si(6) bond length is 2.51 Å. Both Fe(3)-Si(1) bond lengths are 2.32 Å. Both Fe(3)-Si(2) bond lengths are 2.36 Å. In the second Fe site, Fe(1) is bonded to two equivalent Zr(1), two equivalent Zr(3), two equivalent Fe(1), two equivalent Si(3), two equivalent Si(5), and two equivalent Si(6) atoms to form a mixture of distorted face, corner, and edge-sharing FeZr4Fe2Si6 cuboctahedra. Both Fe(1)-Fe(1) bond lengths are 2.57 Å. Both Fe(1)-Si(3) bond lengths are 2.48 Å. Both Fe(1)-Si(5) bond lengths are 2.43 Å. Both Fe(1)-Si(6) bond lengths are 2.44 Å. In the third Fe site, Fe(2) is bonded to two equivalent Zr(1), two equivalent Zr(2), two equivalent Fe(2), two equivalent Si(3), two equivalent Si(4), and two equivalent Si(5) atoms to form a mixture of distorted face, corner, and edge-sharing FeZr4Fe2Si6 cuboctahedra. Both Fe(2)-Fe(2) bond lengths are 2.57 Å. Both Fe(2)-Si(3) bond lengths are 2.46 Å. Both Fe(2)-Si(4) bond lengths are 2.41 Å. Both Fe(2)-Si(5) bond lengths are 2.41 Å. There are six inequivalent Si sites. In the first Si site, Si(5) is bonded in a 8-coordinate geometry to one Zr(3), three equivalent Zr(1), two equivalent Fe(1), and two equivalent Fe(2) atoms. In the second Si site, Si(6) is bonded in a 7-coordinate geometry to one Zr(1), two equivalent Zr(3), one Fe(3), two equivalent Fe(1), and one Si(4) atom. The Si(6)-Si(4) bond length is 2.36 Å. In the third Si site, Si(4) is bonded in a 7-coordinate geometry to three equivalent Zr(2), one Fe(3), two equivalent Fe(2), and one Si(6) atom. In the fourth Si site, Si(1) is bonded in a 8-coordinate geometry to two equivalent Zr(2), two equivalent Zr(3), two equivalent Fe(3), and two equivalent Si(1) atoms. There is one shorter (2.51 Å) and one longer (2.63 Å) Si(1)-Si(1) bond length. In the fifth Si site, Si(2) is bonded in a 10-coordinate geometry to two equivalent Zr(1), two equivalent Zr(2), two equivalent Zr(3), two equivalent Fe(3), and two equivalent Si(2) atoms. Both Si(2)-Si(2) bond lengths are 2.57 Å. In the sixth Si site, Si(3) is bonded in a 7-coordinate geometry to one Zr(1), one Zr(2), one Zr(3), two equivalent Fe(1), and two equivalent Fe(2) atoms.