Ba2MgNd2(Fe2O5)2 crystallizes in the triclinic P1 space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 5-coordinate geometry to one O(2), one O(5), one O(7), and two equivalent O(9) atoms. In the second Ba site, Ba(2) is bonded in a 8-coordinate geometry to one O(3), one O(6), two equivalent O(10), two equivalent O(5), and two equivalent O(8) atoms. Mg(1) is bonded in a square co-planar geometry to one O(1), one O(2), one O(4), and one O(7) atom. There are two inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a 6-coordinate geometry to one O(3), one O(6), two equivalent O(2), and two equivalent O(7) atoms. In the second Nd site, Nd(2) is bonded in a body-centered cubic geometry to one O(1), one O(3), one O(4), one O(6), two equivalent O(10), and two equivalent O(8) atoms. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 5-coordinate geometry to one O(10), one O(2), one O(5), and two equivalent O(6) atoms. In the second Fe site, Fe(2) is bonded to one O(10), one O(9), and two equivalent O(4) atoms to form distorted corner-sharing FeO4 trigonal pyramids. In the third Fe site, Fe(3) is bonded to one O(5), one O(7), one O(8), and two equivalent O(3) atoms to form distorted FeO5 trigonal bipyramids that share corners with two equivalent Fe(3)O5 trigonal bipyramids and  a cornercorner with one Fe(4)O4 trigonal pyramid. In the fourth Fe site, Fe(4) is bonded to one O(8), one O(9), and two equivalent O(1) atoms to form distorted FeO4 trigonal pyramids that share  a cornercorner with one Fe(3)O5 trigonal bipyramid,  a cornercorner with one Fe(2)O4 trigonal pyramid, and corners with two equivalent Fe(4)O4 trigonal pyramids. There are ten inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Nd(2), and two equivalent Fe(4) atoms to form distorted ONdMgFe2 trigonal pyramids that share corners with two equivalent O(9)Ba2Fe2 tetrahedra,  a cornercorner with one O(2)BaNd2MgFe trigonal bipyramid,  a cornercorner with one O(7)BaNd2MgFe trigonal bipyramid, corners with two equivalent O(1)NdMgFe2 trigonal pyramids, and  an edgeedge with one O(4)NdMgFe2 trigonal pyramid. In the second O site, O(2) is bonded to one Ba(1), one Mg(1), two equivalent Nd(1), and one Fe(1) atom to form distorted OBaNd2MgFe trigonal bipyramids that share corners with two equivalent O(9)Ba2Fe2 tetrahedra, corners with two equivalent O(2)BaNd2MgFe trigonal bipyramids, corners with three equivalent O(7)BaNd2MgFe trigonal bipyramids,  a cornercorner with one O(1)NdMgFe2 trigonal pyramid,  a cornercorner with one O(4)NdMgFe2 trigonal pyramid,  an edgeedge with one O(5)Ba3Fe2 trigonal bipyramid, and  a faceface with one O(7)BaNd2MgFe trigonal bipyramid. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Ba(2), one Nd(1), one Nd(2), and two equivalent Fe(3) atoms. In the fourth O site, O(4) is bonded to one Mg(1), one Nd(2), and two equivalent Fe(2) atoms to form distorted ONdMgFe2 trigonal pyramids that share corners with two equivalent O(9)Ba2Fe2 tetrahedra,  a cornercorner with one O(2)BaNd2MgFe trigonal bipyramid,  a cornercorner with one O(7)BaNd2MgFe trigonal bipyramid, corners with two equivalent O(4)NdMgFe2 trigonal pyramids, and  an edgeedge with one O(1)NdMgFe2 trigonal pyramid. In the fifth O site, O(5) is bonded to one Ba(1), two equivalent Ba(2), one Fe(1), and one Fe(3) atom to form distorted OBa3Fe2 trigonal bipyramids that share corners with two equivalent O(9)Ba2Fe2 tetrahedra, corners with two equivalent O(5)Ba3Fe2 trigonal bipyramids,  an edgeedge with one O(2)BaNd2MgFe trigonal bipyramid, and  an edgeedge with one O(7)BaNd2MgFe trigonal bipyramid. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one Ba(2), one Nd(1), one Nd(2), and two equivalent Fe(1) atoms. In the seventh O site, O(7) is bonded to one Ba(1), one Mg(1), two equivalent Nd(1), and one Fe(3) atom to form distorted OBaNd2MgFe trigonal bipyramids that share corners with two equivalent O(9)Ba2Fe2 tetrahedra, corners with two equivalent O(7)BaNd2MgFe trigonal bipyramids, corners with three equivalent O(2)BaNd2MgFe trigonal bipyramids,  a cornercorner with one O(1)NdMgFe2 trigonal pyramid,  a cornercorner with one O(4)NdMgFe2 trigonal pyramid,  an edgeedge with one O(5)Ba3Fe2 trigonal bipyramid, and  a faceface with one O(2)BaNd2MgFe trigonal bipyramid. In the eighth O site, O(8) is bonded in a 6-coordinate geometry to two equivalent Ba(2), two equivalent Nd(2), one Fe(3), and one Fe(4) atom. In the ninth O site, O(9) is bonded to two equivalent Ba(1), one Fe(2), and one Fe(4) atom to form OBa2Fe2 tetrahedra that share corners with two equivalent O(9)Ba2Fe2 tetrahedra, corners with two equivalent O(5)Ba3Fe2 trigonal bipyramids, corners with two equivalent O(2)BaNd2MgFe trigonal bipyramids, corners with two equivalent O(7)BaNd2MgFe trigonal bipyramids, corners with two equivalent O(1)NdMgFe2 trigonal pyramids, and corners with two equivalent O(4)NdMgFe2 trigonal pyramids. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to two equivalent Ba(2), two equivalent Nd(2), one Fe(1), and one Fe(2) atom.
Ba2MgNd2(Fe2O5)2 crystallizes in the triclinic P1 space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 5-coordinate geometry to one O(2), one O(5), one O(7), and two equivalent O(9) atoms. The Ba(1)-O(2) bond length is 2.65 Å. The Ba(1)-O(5) bond length is 2.87 Å. The Ba(1)-O(7) bond length is 2.69 Å. There is one shorter (2.60 Å) and one longer (2.62 Å) Ba(1)-O(9) bond length. In the second Ba site, Ba(2) is bonded in a 8-coordinate geometry to one O(3), one O(6), two equivalent O(10), two equivalent O(5), and two equivalent O(8) atoms. The Ba(2)-O(3) bond length is 2.89 Å. The Ba(2)-O(6) bond length is 2.95 Å. There is one shorter (3.15 Å) and one longer (3.21 Å) Ba(2)-O(10) bond length. There is one shorter (2.66 Å) and one longer (2.73 Å) Ba(2)-O(5) bond length. There is one shorter (2.97 Å) and one longer (3.08 Å) Ba(2)-O(8) bond length. Mg(1) is bonded in a square co-planar geometry to one O(1), one O(2), one O(4), and one O(7) atom. The Mg(1)-O(1) bond length is 1.99 Å. The Mg(1)-O(2) bond length is 2.08 Å. The Mg(1)-O(4) bond length is 2.00 Å. The Mg(1)-O(7) bond length is 2.17 Å. There are two inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a 6-coordinate geometry to one O(3), one O(6), two equivalent O(2), and two equivalent O(7) atoms. The Nd(1)-O(3) bond length is 2.29 Å. The Nd(1)-O(6) bond length is 2.30 Å. There is one shorter (2.46 Å) and one longer (2.47 Å) Nd(1)-O(2) bond length. There is one shorter (2.48 Å) and one longer (2.49 Å) Nd(1)-O(7) bond length. In the second Nd site, Nd(2) is bonded in a body-centered cubic geometry to one O(1), one O(3), one O(4), one O(6), two equivalent O(10), and two equivalent O(8) atoms. The Nd(2)-O(1) bond length is 2.54 Å. The Nd(2)-O(3) bond length is 2.48 Å. The Nd(2)-O(4) bond length is 2.54 Å. The Nd(2)-O(6) bond length is 2.57 Å. There is one shorter (2.49 Å) and one longer (2.50 Å) Nd(2)-O(10) bond length. There is one shorter (2.51 Å) and one longer (2.53 Å) Nd(2)-O(8) bond length. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 5-coordinate geometry to one O(10), one O(2), one O(5), and two equivalent O(6) atoms. The Fe(1)-O(10) bond length is 2.12 Å. The Fe(1)-O(2) bond length is 2.60 Å. The Fe(1)-O(5) bond length is 2.02 Å. There is one shorter (2.00 Å) and one longer (2.03 Å) Fe(1)-O(6) bond length. In the second Fe site, Fe(2) is bonded to one O(10), one O(9), and two equivalent O(4) atoms to form distorted corner-sharing FeO4 trigonal pyramids. The Fe(2)-O(10) bond length is 2.03 Å. The Fe(2)-O(9) bond length is 1.99 Å. There is one shorter (2.08 Å) and one longer (2.09 Å) Fe(2)-O(4) bond length. In the third Fe site, Fe(3) is bonded to one O(5), one O(7), one O(8), and two equivalent O(3) atoms to form distorted FeO5 trigonal bipyramids that share corners with two equivalent Fe(3)O5 trigonal bipyramids and  a cornercorner with one Fe(4)O4 trigonal pyramid. The Fe(3)-O(5) bond length is 1.97 Å. The Fe(3)-O(7) bond length is 2.34 Å. The Fe(3)-O(8) bond length is 2.27 Å. There is one shorter (2.03 Å) and one longer (2.08 Å) Fe(3)-O(3) bond length. In the fourth Fe site, Fe(4) is bonded to one O(8), one O(9), and two equivalent O(1) atoms to form distorted FeO4 trigonal pyramids that share  a cornercorner with one Fe(3)O5 trigonal bipyramid,  a cornercorner with one Fe(2)O4 trigonal pyramid, and corners with two equivalent Fe(4)O4 trigonal pyramids. The Fe(4)-O(8) bond length is 2.02 Å. The Fe(4)-O(9) bond length is 1.99 Å. There is one shorter (2.08 Å) and one longer (2.09 Å) Fe(4)-O(1) bond length. There are ten inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Nd(2), and two equivalent Fe(4) atoms to form distorted ONdMgFe2 trigonal pyramids that share corners with two equivalent O(9)Ba2Fe2 tetrahedra,  a cornercorner with one O(2)BaNd2MgFe trigonal bipyramid,  a cornercorner with one O(7)BaNd2MgFe trigonal bipyramid, corners with two equivalent O(1)NdMgFe2 trigonal pyramids, and  an edgeedge with one O(4)NdMgFe2 trigonal pyramid. In the second O site, O(2) is bonded to one Ba(1), one Mg(1), two equivalent Nd(1), and one Fe(1) atom to form distorted OBaNd2MgFe trigonal bipyramids that share corners with two equivalent O(9)Ba2Fe2 tetrahedra, corners with two equivalent O(2)BaNd2MgFe trigonal bipyramids, corners with three equivalent O(7)BaNd2MgFe trigonal bipyramids,  a cornercorner with one O(1)NdMgFe2 trigonal pyramid,  a cornercorner with one O(4)NdMgFe2 trigonal pyramid,  an edgeedge with one O(5)Ba3Fe2 trigonal bipyramid, and  a faceface with one O(7)BaNd2MgFe trigonal bipyramid. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Ba(2), one Nd(1), one Nd(2), and two equivalent Fe(3) atoms. In the fourth O site, O(4) is bonded to one Mg(1), one Nd(2), and two equivalent Fe(2) atoms to form distorted ONdMgFe2 trigonal pyramids that share corners with two equivalent O(9)Ba2Fe2 tetrahedra,  a cornercorner with one O(2)BaNd2MgFe trigonal bipyramid,  a cornercorner with one O(7)BaNd2MgFe trigonal bipyramid, corners with two equivalent O(4)NdMgFe2 trigonal pyramids, and  an edgeedge with one O(1)NdMgFe2 trigonal pyramid. In the fifth O site, O(5) is bonded to one Ba(1), two equivalent Ba(2), one Fe(1), and one Fe(3) atom to form distorted OBa3Fe2 trigonal bipyramids that share corners with two equivalent O(9)Ba2Fe2 tetrahedra, corners with two equivalent O(5)Ba3Fe2 trigonal bipyramids,  an edgeedge with one O(2)BaNd2MgFe trigonal bipyramid, and  an edgeedge with one O(7)BaNd2MgFe trigonal bipyramid. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one Ba(2), one Nd(1), one Nd(2), and two equivalent Fe(1) atoms. In the seventh O site, O(7) is bonded to one Ba(1), one Mg(1), two equivalent Nd(1), and one Fe(3) atom to form distorted OBaNd2MgFe trigonal bipyramids that share corners with two equivalent O(9)Ba2Fe2 tetrahedra, corners with two equivalent O(7)BaNd2MgFe trigonal bipyramids, corners with three equivalent O(2)BaNd2MgFe trigonal bipyramids,  a cornercorner with one O(1)NdMgFe2 trigonal pyramid,  a cornercorner with one O(4)NdMgFe2 trigonal pyramid,  an edgeedge with one O(5)Ba3Fe2 trigonal bipyramid, and  a faceface with one O(2)BaNd2MgFe trigonal bipyramid. In the eighth O site, O(8) is bonded in a 6-coordinate geometry to two equivalent Ba(2), two equivalent Nd(2), one Fe(3), and one Fe(4) atom. In the ninth O site, O(9) is bonded to two equivalent Ba(1), one Fe(2), and one Fe(4) atom to form OBa2Fe2 tetrahedra that share corners with two equivalent O(9)Ba2Fe2 tetrahedra, corners with two equivalent O(5)Ba3Fe2 trigonal bipyramids, corners with two equivalent O(2)BaNd2MgFe trigonal bipyramids, corners with two equivalent O(7)BaNd2MgFe trigonal bipyramids, corners with two equivalent O(1)NdMgFe2 trigonal pyramids, and corners with two equivalent O(4)NdMgFe2 trigonal pyramids. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to two equivalent Ba(2), two equivalent Nd(2), one Fe(1), and one Fe(2) atom.