CaBaFe4O7 crystallizes in the monoclinic Cc space group. Ba(1) is bonded in a 9-coordinate geometry to one O(4), one O(5), one O(6), two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. Ca(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 CaO6 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(4), one O(5), one O(6), and one O(7) atom to form FeO4 tetrahedra that share corners with three equivalent Ca(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 56-63°. In the second Fe site, Fe(2) is bonded to one O(2), one O(3), one O(4), and one O(7) atom to form FeO4 tetrahedra that share corners with three equivalent Ca(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 44-65°. In the third Fe site, Fe(3) is bonded to one O(1), one O(3), one O(5), and one O(7) atom to form FeO4 tetrahedra that share corners with three equivalent Ca(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 43-70°. In the fourth Fe site, Fe(4) is bonded to one O(1), one O(2), one O(6), and one O(7) atom to form FeO4 tetrahedra that share corners with three equivalent Ca(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 47-61°. There are seven inequivalent O sites. In the first O site, O(6) is bonded to one Ba(1), one Ca(1), one Fe(1), and one Fe(4) atom to form distorted OBaCaFe2 tetrahedra that share corners with two equivalent O(7)Fe4 tetrahedra, corners with three equivalent O(5)BaCaFe2 tetrahedra, and corners with three equivalent O(4)BaCaFe2 trigonal pyramids. In the second 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. In the third O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Ba(1), one Ca(1), one Fe(3), and one Fe(4) atom. In the fourth O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Ba(1), one Ca(1), one Fe(2), and one Fe(4) atom. In the fifth O site, O(3) is bonded in a 3-coordinate geometry to two equivalent Ba(1), one Ca(1), one Fe(2), and one Fe(3) atom. In the sixth O site, O(4) is bonded to one Ba(1), one Ca(1), one Fe(1), and one Fe(2) atom to form distorted OBaCaFe2 trigonal pyramids that share corners with two equivalent O(7)Fe4 tetrahedra, corners with three equivalent O(5)BaCaFe2 tetrahedra, and corners with three equivalent O(6)BaCaFe2 tetrahedra. In the seventh O site, O(5) is bonded to one Ba(1), one Ca(1), one Fe(1), and one Fe(3) atom to form OBaCaFe2 tetrahedra that share corners with two equivalent O(7)Fe4 tetrahedra, corners with three equivalent O(6)BaCaFe2 tetrahedra, and corners with three equivalent O(4)BaCaFe2 trigonal pyramids.
CaBaFe4O7 crystallizes in the monoclinic Cc space group. Ba(1) is bonded in a 9-coordinate geometry to one O(4), one O(5), one O(6), two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. The Ba(1)-O(4) bond length is 2.77 Å. The Ba(1)-O(5) bond length is 2.66 Å. The Ba(1)-O(6) bond length is 2.74 Å. There is one shorter (3.16 Å) and one longer (3.27 Å) Ba(1)-O(1) bond length. There is one shorter (3.17 Å) and one longer (3.34 Å) Ba(1)-O(2) bond length. There is one shorter (3.11 Å) and one longer (3.35 Å) Ba(1)-O(3) bond length. Ca(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 CaO6 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 Ca(1)-O(1) bond length is 2.36 Å. The Ca(1)-O(2) bond length is 2.42 Å. The Ca(1)-O(3) bond length is 2.37 Å. The Ca(1)-O(4) bond length is 2.39 Å. The Ca(1)-O(5) bond length is 2.35 Å. The Ca(1)-O(6) bond length is 2.40 Å. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form FeO4 tetrahedra that share corners with three equivalent Ca(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 56-63°. The Fe(1)-O(4) bond length is 2.02 Å. The Fe(1)-O(5) bond length is 1.98 Å. The Fe(1)-O(6) bond length is 2.05 Å. The Fe(1)-O(7) bond length is 2.13 Å. In the second Fe site, Fe(2) is bonded to one O(2), one O(3), one O(4), and one O(7) atom to form FeO4 tetrahedra that share corners with three equivalent Ca(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 44-65°. The Fe(2)-O(2) bond length is 1.93 Å. The Fe(2)-O(3) bond length is 1.89 Å. The Fe(2)-O(4) bond length is 1.89 Å. The Fe(2)-O(7) bond length is 1.96 Å. In the third Fe site, Fe(3) is bonded to one O(1), one O(3), one O(5), and one O(7) atom to form FeO4 tetrahedra that share corners with three equivalent Ca(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 43-70°. The Fe(3)-O(1) bond length is 2.00 Å. The Fe(3)-O(3) bond length is 1.96 Å. The Fe(3)-O(5) bond length is 1.96 Å. The Fe(3)-O(7) bond length is 2.26 Å. In the fourth Fe site, Fe(4) is bonded to one O(1), one O(2), one O(6), and one O(7) atom to form FeO4 tetrahedra that share corners with three equivalent Ca(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 47-61°. The Fe(4)-O(1) bond length is 1.91 Å. The Fe(4)-O(2) bond length is 1.95 Å. The Fe(4)-O(6) bond length is 1.90 Å. The Fe(4)-O(7) bond length is 1.99 Å. There are seven inequivalent O sites. In the first O site, O(6) is bonded to one Ba(1), one Ca(1), one Fe(1), and one Fe(4) atom to form distorted OBaCaFe2 tetrahedra that share corners with two equivalent O(7)Fe4 tetrahedra, corners with three equivalent O(5)BaCaFe2 tetrahedra, and corners with three equivalent O(4)BaCaFe2 trigonal pyramids. In the second 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. In the third O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Ba(1), one Ca(1), one Fe(3), and one Fe(4) atom. In the fourth O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Ba(1), one Ca(1), one Fe(2), and one Fe(4) atom. In the fifth O site, O(3) is bonded in a 3-coordinate geometry to two equivalent Ba(1), one Ca(1), one Fe(2), and one Fe(3) atom. In the sixth O site, O(4) is bonded to one Ba(1), one Ca(1), one Fe(1), and one Fe(2) atom to form distorted OBaCaFe2 trigonal pyramids that share corners with two equivalent O(7)Fe4 tetrahedra, corners with three equivalent O(5)BaCaFe2 tetrahedra, and corners with three equivalent O(6)BaCaFe2 tetrahedra. In the seventh O site, O(5) is bonded to one Ba(1), one Ca(1), one Fe(1), and one Fe(3) atom to form OBaCaFe2 tetrahedra that share corners with two equivalent O(7)Fe4 tetrahedra, corners with three equivalent O(6)BaCaFe2 tetrahedra, and corners with three equivalent O(4)BaCaFe2 trigonal pyramids.