Mn7Fe3 crystallizes in the monoclinic P2_1 space group. There are seven inequivalent Mn sites. In the first Mn site, Mn(1) is bonded in a 12-coordinate geometry to one Mn(3), one Mn(5), one Mn(7), two equivalent Mn(4), two equivalent Mn(6), one Fe(2), two equivalent Fe(1), and two equivalent Fe(3) atoms. In the second Mn site, Mn(2) is bonded in a 12-coordinate geometry to one Mn(4), one Mn(6), two equivalent Mn(3), two equivalent Mn(5), two equivalent Mn(7), one Fe(1), one Fe(3), and two equivalent Fe(2) atoms. In the third Mn site, Mn(3) is bonded in a 12-coordinate geometry to one Mn(1), one Mn(5), one Mn(7), two equivalent Mn(2), two equivalent Mn(6), one Fe(3), two equivalent Fe(1), and two equivalent Fe(2) atoms. In the fourth Mn site, Mn(4) is bonded in a 12-coordinate geometry to one Mn(2), one Mn(6), two equivalent Mn(1), two equivalent Mn(5), two equivalent Mn(7), one Fe(1), one Fe(2), and two equivalent Fe(3) atoms. In the fifth Mn site, Mn(5) is bonded in a 12-coordinate geometry to one Mn(1), one Mn(3), two equivalent Mn(2), two equivalent Mn(4), two equivalent Mn(7), one Fe(1), one Fe(2), and two equivalent Fe(3) atoms. In the sixth Mn site, Mn(6) is bonded in a 12-coordinate geometry to one Mn(2), one Mn(4), one Mn(7), two equivalent Mn(1), two equivalent Mn(3), one Fe(3), two equivalent Fe(1), and two equivalent Fe(2) atoms. In the seventh Mn site, Mn(7) is bonded in a 3-coordinate geometry to one Mn(1), one Mn(3), one Mn(6), two equivalent Mn(2), two equivalent Mn(4), two equivalent Mn(5), one Fe(2), and two equivalent Fe(3) atoms. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one Mn(2), one Mn(4), one Mn(5), two equivalent Mn(1), two equivalent Mn(3), two equivalent Mn(6), one Fe(3), and two equivalent Fe(2) atoms to form distorted FeMn9Fe3 cuboctahedra that share corners with two equivalent Fe(1)Mn9Fe3 cuboctahedra, corners with four equivalent Fe(2)Mn10Fe2 cuboctahedra, corners with five equivalent Fe(3)Mn11Fe cuboctahedra, faces with two equivalent Fe(2)Mn10Fe2 cuboctahedra, faces with two equivalent Fe(3)Mn11Fe cuboctahedra, and faces with two equivalent Fe(1)Mn9Fe3 cuboctahedra. In the second Fe site, Fe(2) is bonded to one Mn(1), one Mn(4), one Mn(5), one Mn(7), two equivalent Mn(2), two equivalent Mn(3), two equivalent Mn(6), and two equivalent Fe(1) atoms to form distorted FeMn10Fe2 cuboctahedra that share corners with two equivalent Fe(2)Mn10Fe2 cuboctahedra, corners with four equivalent Fe(3)Mn11Fe cuboctahedra, corners with four equivalent Fe(1)Mn9Fe3 cuboctahedra, faces with two equivalent Fe(2)Mn10Fe2 cuboctahedra, faces with two equivalent Fe(1)Mn9Fe3 cuboctahedra, and faces with four equivalent Fe(3)Mn11Fe cuboctahedra. In the third Fe site, Fe(3) is bonded to one Mn(2), one Mn(3), one Mn(6), two equivalent Mn(1), two equivalent Mn(4), two equivalent Mn(5), two equivalent Mn(7), and one Fe(1) atom to form distorted FeMn11Fe cuboctahedra that share corners with two equivalent Fe(3)Mn11Fe cuboctahedra, corners with four equivalent Fe(2)Mn10Fe2 cuboctahedra, corners with five equivalent Fe(1)Mn9Fe3 cuboctahedra, faces with two equivalent Fe(3)Mn11Fe cuboctahedra, faces with two equivalent Fe(1)Mn9Fe3 cuboctahedra, and faces with four equivalent Fe(2)Mn10Fe2 cuboctahedra.
Mn7Fe3 crystallizes in the monoclinic P2_1 space group. There are seven inequivalent Mn sites. In the first Mn site, Mn(1) is bonded in a 12-coordinate geometry to one Mn(3), one Mn(5), one Mn(7), two equivalent Mn(4), two equivalent Mn(6), one Fe(2), two equivalent Fe(1), and two equivalent Fe(3) atoms. The Mn(1)-Mn(3) bond length is 2.51 Å. The Mn(1)-Mn(5) bond length is 2.53 Å. The Mn(1)-Mn(7) bond length is 2.56 Å. There is one shorter (2.52 Å) and one longer (2.58 Å) Mn(1)-Mn(4) bond length. There is one shorter (2.52 Å) and one longer (2.59 Å) Mn(1)-Mn(6) bond length. The Mn(1)-Fe(2) bond length is 2.55 Å. There is one shorter (2.43 Å) and one longer (2.55 Å) Mn(1)-Fe(1) bond length. There is one shorter (2.44 Å) and one longer (2.56 Å) Mn(1)-Fe(3) bond length. In the second Mn site, Mn(2) is bonded in a 12-coordinate geometry to one Mn(4), one Mn(6), two equivalent Mn(3), two equivalent Mn(5), two equivalent Mn(7), one Fe(1), one Fe(3), and two equivalent Fe(2) atoms. The Mn(2)-Mn(4) bond length is 2.53 Å. The Mn(2)-Mn(6) bond length is 2.52 Å. There is one shorter (2.52 Å) and one longer (2.62 Å) Mn(2)-Mn(3) bond length. There is one shorter (2.50 Å) and one longer (2.61 Å) Mn(2)-Mn(5) bond length. There is one shorter (2.43 Å) and one longer (2.55 Å) Mn(2)-Mn(7) bond length. The Mn(2)-Fe(1) bond length is 2.54 Å. The Mn(2)-Fe(3) bond length is 2.55 Å. There is one shorter (2.44 Å) and one longer (2.53 Å) Mn(2)-Fe(2) bond length. In the third Mn site, Mn(3) is bonded in a 12-coordinate geometry to one Mn(1), one Mn(5), one Mn(7), two equivalent Mn(2), two equivalent Mn(6), one Fe(3), two equivalent Fe(1), and two equivalent Fe(2) atoms. The Mn(3)-Mn(5) bond length is 2.60 Å. The Mn(3)-Mn(7) bond length is 2.43 Å. There is one shorter (2.51 Å) and one longer (2.52 Å) Mn(3)-Mn(6) bond length. The Mn(3)-Fe(3) bond length is 2.56 Å. There is one shorter (2.54 Å) and one longer (2.57 Å) Mn(3)-Fe(1) bond length. There is one shorter (2.47 Å) and one longer (2.56 Å) Mn(3)-Fe(2) bond length. In the fourth Mn site, Mn(4) is bonded in a 12-coordinate geometry to one Mn(2), one Mn(6), two equivalent Mn(1), two equivalent Mn(5), two equivalent Mn(7), one Fe(1), one Fe(2), and two equivalent Fe(3) atoms. The Mn(4)-Mn(6) bond length is 2.61 Å. There is one shorter (2.54 Å) and one longer (2.55 Å) Mn(4)-Mn(5) bond length. There is one shorter (2.56 Å) and one longer (2.59 Å) Mn(4)-Mn(7) bond length. The Mn(4)-Fe(1) bond length is 2.42 Å. The Mn(4)-Fe(2) bond length is 2.55 Å. There is one shorter (2.45 Å) and one longer (2.57 Å) Mn(4)-Fe(3) bond length. In the fifth Mn site, Mn(5) is bonded in a 12-coordinate geometry to one Mn(1), one Mn(3), two equivalent Mn(2), two equivalent Mn(4), two equivalent Mn(7), one Fe(1), one Fe(2), and two equivalent Fe(3) atoms. There is one shorter (2.46 Å) and one longer (2.57 Å) Mn(5)-Mn(7) bond length. The Mn(5)-Fe(1) bond length is 2.54 Å. The Mn(5)-Fe(2) bond length is 2.41 Å. There is one shorter (2.55 Å) and one longer (2.57 Å) Mn(5)-Fe(3) bond length. In the sixth Mn site, Mn(6) is bonded in a 12-coordinate geometry to one Mn(2), one Mn(4), one Mn(7), two equivalent Mn(1), two equivalent Mn(3), one Fe(3), two equivalent Fe(1), and two equivalent Fe(2) atoms. The Mn(6)-Mn(7) bond length is 2.58 Å. The Mn(6)-Fe(3) bond length is 2.45 Å. There is one shorter (2.45 Å) and one longer (2.55 Å) Mn(6)-Fe(1) bond length. There is one shorter (2.54 Å) and one longer (2.57 Å) Mn(6)-Fe(2) bond length. In the seventh Mn site, Mn(7) is bonded in a 3-coordinate geometry to one Mn(1), one Mn(3), one Mn(6), two equivalent Mn(2), two equivalent Mn(4), two equivalent Mn(5), one Fe(2), and two equivalent Fe(3) atoms. The Mn(7)-Fe(2) bond length is 2.26 Å. Both Mn(7)-Fe(3) bond lengths are 2.29 Å. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one Mn(2), one Mn(4), one Mn(5), two equivalent Mn(1), two equivalent Mn(3), two equivalent Mn(6), one Fe(3), and two equivalent Fe(2) atoms to form distorted FeMn9Fe3 cuboctahedra that share corners with two equivalent Fe(1)Mn9Fe3 cuboctahedra, corners with four equivalent Fe(2)Mn10Fe2 cuboctahedra, corners with five equivalent Fe(3)Mn11Fe cuboctahedra, faces with two equivalent Fe(2)Mn10Fe2 cuboctahedra, faces with two equivalent Fe(3)Mn11Fe cuboctahedra, and faces with two equivalent Fe(1)Mn9Fe3 cuboctahedra. The Fe(1)-Fe(3) bond length is 2.28 Å. There is one shorter (2.30 Å) and one longer (2.31 Å) Fe(1)-Fe(2) bond length. In the second Fe site, Fe(2) is bonded to one Mn(1), one Mn(4), one Mn(5), one Mn(7), two equivalent Mn(2), two equivalent Mn(3), two equivalent Mn(6), and two equivalent Fe(1) atoms to form distorted FeMn10Fe2 cuboctahedra that share corners with two equivalent Fe(2)Mn10Fe2 cuboctahedra, corners with four equivalent Fe(3)Mn11Fe cuboctahedra, corners with four equivalent Fe(1)Mn9Fe3 cuboctahedra, faces with two equivalent Fe(2)Mn10Fe2 cuboctahedra, faces with two equivalent Fe(1)Mn9Fe3 cuboctahedra, and faces with four equivalent Fe(3)Mn11Fe cuboctahedra. In the third Fe site, Fe(3) is bonded to one Mn(2), one Mn(3), one Mn(6), two equivalent Mn(1), two equivalent Mn(4), two equivalent Mn(5), two equivalent Mn(7), and one Fe(1) atom to form distorted FeMn11Fe cuboctahedra that share corners with two equivalent Fe(3)Mn11Fe cuboctahedra, corners with four equivalent Fe(2)Mn10Fe2 cuboctahedra, corners with five equivalent Fe(1)Mn9Fe3 cuboctahedra, faces with two equivalent Fe(3)Mn11Fe cuboctahedra, faces with two equivalent Fe(1)Mn9Fe3 cuboctahedra, and faces with four equivalent Fe(2)Mn10Fe2 cuboctahedra.