Ba6Nd2Fe4O15 crystallizes in the monoclinic Cc space group. There are six inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to one O(10), one O(11), one O(12), one O(13), one O(14), one O(15), one O(4), one O(5), one O(6), one O(7), one O(8), and one O(9) atom to form distorted BaO12 cuboctahedra that share faces with two equivalent Fe(1)O6 octahedra,  a faceface with one Fe(2)O4 tetrahedra,  a faceface with one Fe(3)O4 tetrahedra, and  a faceface with one Fe(4)O4 tetrahedra. In the second Ba site, Ba(2) is bonded in a 10-coordinate geometry to one O(13), one O(14), one O(3), one O(5), one O(7), one O(8), two equivalent O(11), and two equivalent O(2) atoms. In the third Ba site, Ba(3) is bonded in a 10-coordinate geometry to one O(10), one O(12), one O(3), one O(6), one O(7), one O(9), two equivalent O(1), and two equivalent O(15) atoms. In the fourth Ba site, Ba(4) is bonded in a 10-coordinate geometry to one O(1), one O(10), one O(12), one O(13), one O(14), one O(2), one O(3), one O(4), one O(8), and one O(9) atom. In the fifth Ba site, Ba(5) is bonded in a 8-coordinate geometry to one O(10), one O(12), one O(13), one O(14), one O(4), one O(6), one O(8), and one O(9) atom. In the sixth Ba site, Ba(6) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form BaO6 octahedra that share corners with two equivalent Fe(2)O4 tetrahedra, corners with two equivalent Fe(3)O4 tetrahedra, corners with two equivalent Fe(4)O4 tetrahedra, and faces with two equivalent Ba(6)O6 octahedra. There are two inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a 8-coordinate geometry to one O(10), one O(12), one O(13), one O(14), one O(4), one O(5), one O(8), and one O(9) atom. In the second Nd site, Nd(2) is bonded in a 8-coordinate geometry to one O(5), one O(6), two equivalent O(11), two equivalent O(15), and two equivalent O(7) atoms. 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), one O(7), one O(8), and one O(9) atom to form FeO6 octahedra that share  a cornercorner with one Fe(2)O4 tetrahedra,  a cornercorner with one Fe(3)O4 tetrahedra,  a cornercorner with one Fe(4)O4 tetrahedra, and faces with two equivalent Ba(1)O12 cuboctahedra. In the second Fe site, Fe(2) is bonded to one O(10), one O(14), one O(3), and one O(4) atom to form FeO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Ba(6)O6 octahedra, and  a faceface with one Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 8-69°. In the third Fe site, Fe(3) is bonded to one O(1), one O(12), one O(15), and one O(6) atom to form FeO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Ba(6)O6 octahedra, and  a faceface with one Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 9-68°. In the fourth Fe site, Fe(4) is bonded to one O(11), one O(13), one O(2), and one O(5) atom to form FeO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Ba(6)O6 octahedra, and  a faceface with one Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 5-66°. There are fifteen inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Ba(4), two equivalent Ba(3), two equivalent Ba(6), and one Fe(3) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Ba(4), two equivalent Ba(2), two equivalent Ba(6), and one Fe(4) atom. In the third O site, O(3) is bonded in a 6-coordinate geometry to one Ba(2), one Ba(3), one Ba(4), two equivalent Ba(6), and one Fe(2) atom. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(4), one Ba(5), one Nd(1), one Fe(1), and one Fe(2) atom. In the fifth O site, O(5) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(2), one Nd(1), one Nd(2), one Fe(1), and one Fe(4) atom. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(3), one Ba(5), one Nd(2), one Fe(1), and one Fe(3) atom. In the seventh O site, O(7) is bonded to one Ba(1), one Ba(2), one Ba(3), two equivalent Nd(2), and one Fe(1) atom to form distorted OBa3Nd2Fe octahedra that share corners with two equivalent O(7)Ba3Nd2Fe octahedra,  a faceface with one O(8)Ba4NdFe octahedra, and  a faceface with one O(9)Ba4NdFe octahedra. The corner-sharing octahedral tilt angles are 33°. In the eighth O site, O(8) is bonded to one Ba(1), one Ba(2), one Ba(4), one Ba(5), one Nd(1), and one Fe(1) atom to form distorted OBa4NdFe octahedra that share corners with two equivalent O(9)Ba4NdFe octahedra,  a faceface with one O(7)Ba3Nd2Fe octahedra, and  a faceface with one O(9)Ba4NdFe octahedra. The corner-sharing octahedral tilt angles are 34°. In the ninth O site, O(9) is bonded to one Ba(1), one Ba(3), one Ba(4), one Ba(5), one Nd(1), and one Fe(1) atom to form distorted OBa4NdFe octahedra that share corners with two equivalent O(8)Ba4NdFe octahedra,  a faceface with one O(7)Ba3Nd2Fe octahedra, and  a faceface with one O(8)Ba4NdFe octahedra. The corner-sharing octahedral tilt angles are 34°. In the tenth O site, O(10) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(3), one Ba(4), one Ba(5), one Nd(1), and one Fe(2) atom. In the eleventh O site, O(11) is bonded in a 6-coordinate geometry to one Ba(1), two equivalent Ba(2), two equivalent Nd(2), and one Fe(4) atom. In the twelfth O site, O(12) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(3), one Ba(4), one Ba(5), one Nd(1), and one Fe(3) atom. In the thirteenth O site, O(13) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(2), one Ba(4), one Ba(5), one Nd(1), and one Fe(4) atom. In the fourteenth O site, O(14) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(2), one Ba(4), one Ba(5), one Nd(1), and one Fe(2) atom. In the fifteenth O site, O(15) is bonded in a 2-coordinate geometry to one Ba(1), two equivalent Ba(3), two equivalent Nd(2), and one Fe(3) atom.
Ba6Nd2Fe4O15 crystallizes in the monoclinic Cc space group. There are six inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to one O(10), one O(11), one O(12), one O(13), one O(14), one O(15), one O(4), one O(5), one O(6), one O(7), one O(8), and one O(9) atom to form distorted BaO12 cuboctahedra that share faces with two equivalent Fe(1)O6 octahedra,  a faceface with one Fe(2)O4 tetrahedra,  a faceface with one Fe(3)O4 tetrahedra, and  a faceface with one Fe(4)O4 tetrahedra. The Ba(1)-O(10) bond length is 3.30 Å. The Ba(1)-O(11) bond length is 3.24 Å. The Ba(1)-O(12) bond length is 3.26 Å. The Ba(1)-O(13) bond length is 3.27 Å. The Ba(1)-O(14) bond length is 3.27 Å. The Ba(1)-O(15) bond length is 3.24 Å. The Ba(1)-O(4) bond length is 3.11 Å. The Ba(1)-O(5) bond length is 3.15 Å. The Ba(1)-O(6) bond length is 3.14 Å. The Ba(1)-O(7) bond length is 2.82 Å. The Ba(1)-O(8) bond length is 2.82 Å. The Ba(1)-O(9) bond length is 2.72 Å. In the second Ba site, Ba(2) is bonded in a 10-coordinate geometry to one O(13), one O(14), one O(3), one O(5), one O(7), one O(8), two equivalent O(11), and two equivalent O(2) atoms. The Ba(2)-O(13) bond length is 3.26 Å. The Ba(2)-O(14) bond length is 2.96 Å. The Ba(2)-O(3) bond length is 3.15 Å. The Ba(2)-O(5) bond length is 2.74 Å. The Ba(2)-O(7) bond length is 2.88 Å. The Ba(2)-O(8) bond length is 2.81 Å. There is one shorter (2.90 Å) and one longer (3.18 Å) Ba(2)-O(11) bond length. There is one shorter (3.12 Å) and one longer (3.25 Å) Ba(2)-O(2) bond length. In the third Ba site, Ba(3) is bonded in a 10-coordinate geometry to one O(10), one O(12), one O(3), one O(6), one O(7), one O(9), two equivalent O(1), and two equivalent O(15) atoms. The Ba(3)-O(10) bond length is 2.82 Å. The Ba(3)-O(12) bond length is 2.91 Å. The Ba(3)-O(3) bond length is 3.32 Å. The Ba(3)-O(6) bond length is 2.81 Å. The Ba(3)-O(7) bond length is 2.89 Å. The Ba(3)-O(9) bond length is 2.82 Å. There is one shorter (3.22 Å) and one longer (3.24 Å) Ba(3)-O(1) bond length. There is one shorter (2.94 Å) and one longer (3.13 Å) Ba(3)-O(15) bond length. In the fourth Ba site, Ba(4) is bonded in a 10-coordinate geometry to one O(1), one O(10), one O(12), one O(13), one O(14), one O(2), one O(3), one O(4), one O(8), and one O(9) atom. The Ba(4)-O(1) bond length is 3.24 Å. The Ba(4)-O(10) bond length is 3.23 Å. The Ba(4)-O(12) bond length is 3.05 Å. The Ba(4)-O(13) bond length is 2.86 Å. The Ba(4)-O(14) bond length is 2.93 Å. The Ba(4)-O(2) bond length is 3.30 Å. The Ba(4)-O(3) bond length is 3.23 Å. The Ba(4)-O(4) bond length is 2.80 Å. The Ba(4)-O(8) bond length is 2.90 Å. The Ba(4)-O(9) bond length is 2.86 Å. In the fifth Ba site, Ba(5) is bonded in a 8-coordinate geometry to one O(10), one O(12), one O(13), one O(14), one O(4), one O(6), one O(8), and one O(9) atom. The Ba(5)-O(10) bond length is 2.56 Å. The Ba(5)-O(12) bond length is 2.88 Å. The Ba(5)-O(13) bond length is 2.59 Å. The Ba(5)-O(14) bond length is 2.90 Å. The Ba(5)-O(4) bond length is 2.73 Å. The Ba(5)-O(6) bond length is 2.74 Å. The Ba(5)-O(8) bond length is 2.59 Å. The Ba(5)-O(9) bond length is 2.83 Å. In the sixth Ba site, Ba(6) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form BaO6 octahedra that share corners with two equivalent Fe(2)O4 tetrahedra, corners with two equivalent Fe(3)O4 tetrahedra, corners with two equivalent Fe(4)O4 tetrahedra, and faces with two equivalent Ba(6)O6 octahedra. There is one shorter (2.65 Å) and one longer (2.77 Å) Ba(6)-O(1) bond length. There is one shorter (2.60 Å) and one longer (2.77 Å) Ba(6)-O(2) bond length. There is one shorter (2.61 Å) and one longer (2.77 Å) Ba(6)-O(3) bond length. There are two inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a 8-coordinate geometry to one O(10), one O(12), one O(13), one O(14), one O(4), one O(5), one O(8), and one O(9) atom. The Nd(1)-O(10) bond length is 2.63 Å. The Nd(1)-O(12) bond length is 2.42 Å. The Nd(1)-O(13) bond length is 2.59 Å. The Nd(1)-O(14) bond length is 2.41 Å. The Nd(1)-O(4) bond length is 2.51 Å. The Nd(1)-O(5) bond length is 2.70 Å. The Nd(1)-O(8) bond length is 2.73 Å. The Nd(1)-O(9) bond length is 2.51 Å. In the second Nd site, Nd(2) is bonded in a 8-coordinate geometry to one O(5), one O(6), two equivalent O(11), two equivalent O(15), and two equivalent O(7) atoms. The Nd(2)-O(5) bond length is 2.55 Å. The Nd(2)-O(6) bond length is 2.47 Å. There is one shorter (2.37 Å) and one longer (2.73 Å) Nd(2)-O(11) bond length. There is one shorter (2.36 Å) and one longer (2.75 Å) Nd(2)-O(15) bond length. There is one shorter (2.42 Å) and one longer (2.70 Å) Nd(2)-O(7) bond length. 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), one O(7), one O(8), and one O(9) atom to form FeO6 octahedra that share  a cornercorner with one Fe(2)O4 tetrahedra,  a cornercorner with one Fe(3)O4 tetrahedra,  a cornercorner with one Fe(4)O4 tetrahedra, and faces with two equivalent Ba(1)O12 cuboctahedra. The Fe(1)-O(4) bond length is 2.20 Å. The Fe(1)-O(5) bond length is 2.18 Å. The Fe(1)-O(6) bond length is 2.18 Å. The Fe(1)-O(7) bond length is 2.01 Å. The Fe(1)-O(8) bond length is 1.94 Å. The Fe(1)-O(9) bond length is 2.00 Å. In the second Fe site, Fe(2) is bonded to one O(10), one O(14), one O(3), and one O(4) atom to form FeO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Ba(6)O6 octahedra, and  a faceface with one Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 8-69°. The Fe(2)-O(10) bond length is 1.87 Å. The Fe(2)-O(14) bond length is 1.92 Å. The Fe(2)-O(3) bond length is 1.86 Å. The Fe(2)-O(4) bond length is 1.95 Å. In the third Fe site, Fe(3) is bonded to one O(1), one O(12), one O(15), and one O(6) atom to form FeO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Ba(6)O6 octahedra, and  a faceface with one Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 9-68°. The Fe(3)-O(1) bond length is 1.87 Å. The Fe(3)-O(12) bond length is 1.91 Å. The Fe(3)-O(15) bond length is 1.90 Å. The Fe(3)-O(6) bond length is 1.95 Å. In the fourth Fe site, Fe(4) is bonded to one O(11), one O(13), one O(2), and one O(5) atom to form FeO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Ba(6)O6 octahedra, and  a faceface with one Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 5-66°. The Fe(4)-O(11) bond length is 1.91 Å. The Fe(4)-O(13) bond length is 1.87 Å. The Fe(4)-O(2) bond length is 1.86 Å. The Fe(4)-O(5) bond length is 1.93 Å. There are fifteen inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Ba(4), two equivalent Ba(3), two equivalent Ba(6), and one Fe(3) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Ba(4), two equivalent Ba(2), two equivalent Ba(6), and one Fe(4) atom. In the third O site, O(3) is bonded in a 6-coordinate geometry to one Ba(2), one Ba(3), one Ba(4), two equivalent Ba(6), and one Fe(2) atom. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(4), one Ba(5), one Nd(1), one Fe(1), and one Fe(2) atom. In the fifth O site, O(5) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(2), one Nd(1), one Nd(2), one Fe(1), and one Fe(4) atom. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(3), one Ba(5), one Nd(2), one Fe(1), and one Fe(3) atom. In the seventh O site, O(7) is bonded to one Ba(1), one Ba(2), one Ba(3), two equivalent Nd(2), and one Fe(1) atom to form distorted OBa3Nd2Fe octahedra that share corners with two equivalent O(7)Ba3Nd2Fe octahedra,  a faceface with one O(8)Ba4NdFe octahedra, and  a faceface with one O(9)Ba4NdFe octahedra. The corner-sharing octahedral tilt angles are 33°. In the eighth O site, O(8) is bonded to one Ba(1), one Ba(2), one Ba(4), one Ba(5), one Nd(1), and one Fe(1) atom to form distorted OBa4NdFe octahedra that share corners with two equivalent O(9)Ba4NdFe octahedra,  a faceface with one O(7)Ba3Nd2Fe octahedra, and  a faceface with one O(9)Ba4NdFe octahedra. The corner-sharing octahedral tilt angles are 34°. In the ninth O site, O(9) is bonded to one Ba(1), one Ba(3), one Ba(4), one Ba(5), one Nd(1), and one Fe(1) atom to form distorted OBa4NdFe octahedra that share corners with two equivalent O(8)Ba4NdFe octahedra,  a faceface with one O(7)Ba3Nd2Fe octahedra, and  a faceface with one O(8)Ba4NdFe octahedra. The corner-sharing octahedral tilt angles are 34°. In the tenth O site, O(10) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(3), one Ba(4), one Ba(5), one Nd(1), and one Fe(2) atom. In the eleventh O site, O(11) is bonded in a 6-coordinate geometry to one Ba(1), two equivalent Ba(2), two equivalent Nd(2), and one Fe(4) atom. In the twelfth O site, O(12) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(3), one Ba(4), one Ba(5), one Nd(1), and one Fe(3) atom. In the thirteenth O site, O(13) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(2), one Ba(4), one Ba(5), one Nd(1), and one Fe(4) atom. In the fourteenth O site, O(14) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(2), one Ba(4), one Ba(5), one Nd(1), and one Fe(2) atom. In the fifteenth O site, O(15) is bonded in a 2-coordinate geometry to one Ba(1), two equivalent Ba(3), two equivalent Nd(2), and one Fe(3) atom.