BaHoFe4O7 crystallizes in the monoclinic P2_1 space group. Ba(1) is bonded in a 8-coordinate geometry to one O(3), one O(4), one O(5), one O(6), two equivalent O(1), and two equivalent O(2) atoms. Ho(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form HoO6 octahedra that share corners with three equivalent Fe(1)O4 tetrahedra, corners with three equivalent Fe(2)O4 tetrahedra, corners with three equivalent Fe(3)O4 tetrahedra, and corners with three equivalent Fe(4)O4 tetrahedra. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(2), one O(4), one O(6), and one O(7) atom to form FeO4 tetrahedra that share corners with three equivalent Ho(1)O6 octahedra, corners with two equivalent Fe(2)O4 tetrahedra, corners with two equivalent Fe(3)O4 tetrahedra, and corners with two equivalent Fe(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 47-59°. In the second Fe site, Fe(2) is bonded to one O(1), one O(3), one O(6), and one O(7) atom to form FeO4 tetrahedra that share corners with three equivalent Ho(1)O6 octahedra, corners with two equivalent Fe(1)O4 tetrahedra, corners with two equivalent Fe(3)O4 tetrahedra, and corners with two equivalent Fe(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 52-67°. In the third Fe site, Fe(3) is bonded to one O(1), one O(4), one O(5), and one O(7) atom to form FeO4 tetrahedra that share corners with three equivalent Ho(1)O6 octahedra, corners with two equivalent Fe(1)O4 tetrahedra, corners with two equivalent Fe(2)O4 tetrahedra, and corners with two equivalent Fe(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 52-67°. In the fourth Fe site, Fe(4) is bonded to one O(2), one O(3), one O(5), and one O(7) atom to form FeO4 tetrahedra that share corners with three equivalent Ho(1)O6 octahedra, corners with two equivalent Fe(1)O4 tetrahedra, corners with two equivalent Fe(2)O4 tetrahedra, and corners with two equivalent Fe(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 47-63°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Ba(1), one Ho(1), one Fe(2), and one Fe(3) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Ba(1), one Ho(1), one Fe(1), and one Fe(4) atom. In the third O site, O(3) is bonded to one Ba(1), one Ho(1), one Fe(2), and one Fe(4) atom to form distorted OBaHoFe2 tetrahedra that share corners with two equivalent O(7)Fe4 tetrahedra and corners with three equivalent O(5)BaHoFe2 tetrahedra. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Ba(1), one Ho(1), one Fe(1), and one Fe(3) atom. In the fifth O site, O(5) is bonded to one Ba(1), one Ho(1), one Fe(3), and one Fe(4) atom to form distorted OBaHoFe2 tetrahedra that share corners with two equivalent O(7)Fe4 tetrahedra and corners with three equivalent O(3)BaHoFe2 tetrahedra. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Ba(1), one Ho(1), one Fe(1), and one Fe(2) atom. In the seventh O site, O(7) is bonded to one Fe(1), one Fe(2), one Fe(3), and one Fe(4) atom to form corner-sharing OFe4 tetrahedra.
BaHoFe4O7 crystallizes in the monoclinic P2_1 space group. Ba(1) is bonded in a 8-coordinate geometry to one O(3), one O(4), one O(5), one O(6), two equivalent O(1), and two equivalent O(2) atoms. The Ba(1)-O(3) bond length is 2.78 Å. The Ba(1)-O(4) bond length is 2.84 Å. The Ba(1)-O(5) bond length is 2.78 Å. The Ba(1)-O(6) bond length is 2.78 Å. There is one shorter (3.00 Å) and one longer (3.30 Å) Ba(1)-O(1) bond length. There is one shorter (3.04 Å) and one longer (3.37 Å) Ba(1)-O(2) bond length. Ho(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form HoO6 octahedra that share corners with three equivalent Fe(1)O4 tetrahedra, corners with three equivalent Fe(2)O4 tetrahedra, corners with three equivalent Fe(3)O4 tetrahedra, and corners with three equivalent Fe(4)O4 tetrahedra. The Ho(1)-O(1) bond length is 2.23 Å. The Ho(1)-O(2) bond length is 2.35 Å. The Ho(1)-O(3) bond length is 2.25 Å. The Ho(1)-O(4) bond length is 2.29 Å. The Ho(1)-O(5) bond length is 2.28 Å. The Ho(1)-O(6) bond length is 2.31 Å. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(2), one O(4), one O(6), and one O(7) atom to form FeO4 tetrahedra that share corners with three equivalent Ho(1)O6 octahedra, corners with two equivalent Fe(2)O4 tetrahedra, corners with two equivalent Fe(3)O4 tetrahedra, and corners with two equivalent Fe(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 47-59°. The Fe(1)-O(2) bond length is 1.93 Å. The Fe(1)-O(4) bond length is 1.92 Å. The Fe(1)-O(6) bond length is 1.93 Å. The Fe(1)-O(7) bond length is 1.94 Å. In the second Fe site, Fe(2) is bonded to one O(1), one O(3), one O(6), and one O(7) atom to form FeO4 tetrahedra that share corners with three equivalent Ho(1)O6 octahedra, corners with two equivalent Fe(1)O4 tetrahedra, corners with two equivalent Fe(3)O4 tetrahedra, and corners with two equivalent Fe(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 52-67°. The Fe(2)-O(1) bond length is 2.04 Å. The Fe(2)-O(3) bond length is 1.99 Å. The Fe(2)-O(6) bond length is 2.06 Å. The Fe(2)-O(7) bond length is 2.04 Å. In the third Fe site, Fe(3) is bonded to one O(1), one O(4), one O(5), and one O(7) atom to form FeO4 tetrahedra that share corners with three equivalent Ho(1)O6 octahedra, corners with two equivalent Fe(1)O4 tetrahedra, corners with two equivalent Fe(2)O4 tetrahedra, and corners with two equivalent Fe(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 52-67°. The Fe(3)-O(1) bond length is 1.98 Å. The Fe(3)-O(4) bond length is 2.07 Å. The Fe(3)-O(5) bond length is 2.03 Å. The Fe(3)-O(7) bond length is 2.08 Å. In the fourth Fe site, Fe(4) is bonded to one O(2), one O(3), one O(5), and one O(7) atom to form FeO4 tetrahedra that share corners with three equivalent Ho(1)O6 octahedra, corners with two equivalent Fe(1)O4 tetrahedra, corners with two equivalent Fe(2)O4 tetrahedra, and corners with two equivalent Fe(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 47-63°. The Fe(4)-O(2) bond length is 2.04 Å. The Fe(4)-O(3) bond length is 1.98 Å. The Fe(4)-O(5) bond length is 1.97 Å. The Fe(4)-O(7) bond length is 2.14 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Ba(1), one Ho(1), one Fe(2), and one Fe(3) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Ba(1), one Ho(1), one Fe(1), and one Fe(4) atom. In the third O site, O(3) is bonded to one Ba(1), one Ho(1), one Fe(2), and one Fe(4) atom to form distorted OBaHoFe2 tetrahedra that share corners with two equivalent O(7)Fe4 tetrahedra and corners with three equivalent O(5)BaHoFe2 tetrahedra. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Ba(1), one Ho(1), one Fe(1), and one Fe(3) atom. In the fifth O site, O(5) is bonded to one Ba(1), one Ho(1), one Fe(3), and one Fe(4) atom to form distorted OBaHoFe2 tetrahedra that share corners with two equivalent O(7)Fe4 tetrahedra and corners with three equivalent O(3)BaHoFe2 tetrahedra. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Ba(1), one Ho(1), one Fe(1), and one Fe(2) atom. In the seventh O site, O(7) is bonded to one Fe(1), one Fe(2), one Fe(3), and one Fe(4) atom to form corner-sharing OFe4 tetrahedra.