Mn5Fe5Si6 crystallizes in the orthorhombic Amm2 space group. There are three inequivalent Mn sites. In the first Mn site, Mn(1) is bonded in a 5-coordinate geometry to one Fe(2), one Si(1), two equivalent Si(2), and two equivalent Si(4) atoms. In the second Mn site, Mn(2) is bonded in a 5-coordinate geometry to one Si(3), two equivalent Si(1), and two equivalent Si(4) atoms. In the third Mn site, Mn(3) is bonded in a 5-coordinate geometry to two equivalent Fe(2), one Si(3), two equivalent Si(2), and two equivalent Si(4) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 8-coordinate geometry to two equivalent Fe(1), one Si(1), one Si(3), two equivalent Si(2), and two equivalent Si(4) atoms. In the second Fe site, Fe(2) is bonded in a 11-coordinate geometry to two equivalent Mn(1), four equivalent Mn(3), one Si(1), two equivalent Si(2), and two equivalent Si(3) atoms. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to two equivalent Mn(1), two equivalent Mn(2), one Fe(2), and four equivalent Fe(1) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to two equivalent Mn(1), two equivalent Mn(3), one Fe(2), and four equivalent Fe(1) atoms. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to one Mn(2), two equivalent Mn(3), two equivalent Fe(2), and four equivalent Fe(1) atoms. In the fourth Si site, Si(4) is bonded in a 9-coordinate geometry to one Mn(2), two equivalent Mn(1), two equivalent Mn(3), and four equivalent Fe(1) atoms.
Mn5Fe5Si6 crystallizes in the orthorhombic Amm2 space group. There are three inequivalent Mn sites. In the first Mn site, Mn(1) is bonded in a 5-coordinate geometry to one Fe(2), one Si(1), two equivalent Si(2), and two equivalent Si(4) atoms. The Mn(1)-Fe(2) bond length is 2.88 Å. The Mn(1)-Si(1) bond length is 2.40 Å. There is one shorter (2.40 Å) and one longer (2.51 Å) Mn(1)-Si(2) bond length. Both Mn(1)-Si(4) bond lengths are 2.61 Å. In the second Mn site, Mn(2) is bonded in a 5-coordinate geometry to one Si(3), two equivalent Si(1), and two equivalent Si(4) atoms. The Mn(2)-Si(3) bond length is 2.45 Å. Both Mn(2)-Si(1) bond lengths are 2.60 Å. Both Mn(2)-Si(4) bond lengths are 2.37 Å. In the third Mn site, Mn(3) is bonded in a 5-coordinate geometry to two equivalent Fe(2), one Si(3), two equivalent Si(2), and two equivalent Si(4) atoms. Both Mn(3)-Fe(2) bond lengths are 2.86 Å. The Mn(3)-Si(3) bond length is 2.39 Å. Both Mn(3)-Si(2) bond lengths are 2.61 Å. There is one shorter (2.40 Å) and one longer (2.50 Å) Mn(3)-Si(4) bond length. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 8-coordinate geometry to two equivalent Fe(1), one Si(1), one Si(3), two equivalent Si(2), and two equivalent Si(4) atoms. There is one shorter (2.34 Å) and one longer (2.35 Å) Fe(1)-Fe(1) bond length. The Fe(1)-Si(1) bond length is 2.39 Å. The Fe(1)-Si(3) bond length is 2.40 Å. Both Fe(1)-Si(2) bond lengths are 2.40 Å. There is one shorter (2.37 Å) and one longer (2.38 Å) Fe(1)-Si(4) bond length. In the second Fe site, Fe(2) is bonded in a 11-coordinate geometry to two equivalent Mn(1), four equivalent Mn(3), one Si(1), two equivalent Si(2), and two equivalent Si(3) atoms. The Fe(2)-Si(1) bond length is 2.37 Å. Both Fe(2)-Si(2) bond lengths are 2.32 Å. Both Fe(2)-Si(3) bond lengths are 2.57 Å. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to two equivalent Mn(1), two equivalent Mn(2), one Fe(2), and four equivalent Fe(1) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to two equivalent Mn(1), two equivalent Mn(3), one Fe(2), and four equivalent Fe(1) atoms. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to one Mn(2), two equivalent Mn(3), two equivalent Fe(2), and four equivalent Fe(1) atoms. In the fourth Si site, Si(4) is bonded in a 9-coordinate geometry to one Mn(2), two equivalent Mn(1), two equivalent Mn(3), and four equivalent Fe(1) atoms.