Ba2MgPr(CuO2)4 crystallizes in the monoclinic Pm space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 7-coordinate geometry to one O(5), two equivalent O(1), and four equivalent O(7) atoms. In the second Ba site, Ba(2) is bonded in a 10-coordinate geometry to two equivalent O(2), two equivalent O(4), two equivalent O(6), and four equivalent O(8) atoms. Mg(1) is bonded in a distorted see-saw-like geometry to one O(3), one O(7), and two equivalent O(5) atoms. Pr(1) is bonded in a 6-coordinate geometry to two equivalent O(3), two equivalent O(4), and two equivalent O(6) atoms. There are four inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a distorted linear geometry to two equivalent O(3) and two equivalent O(5) atoms. In the second Cu site, Cu(2) is bonded to one O(8), two equivalent O(4), and two equivalent O(6) atoms to form corner-sharing CuO5 trigonal bipyramids. In the third Cu site, Cu(3) is bonded in a square co-planar geometry to one O(2), one O(7), and two equivalent O(1) atoms. In the fourth Cu site, Cu(4) is bonded in a square co-planar geometry to one O(1), one O(8), and two equivalent O(2) atoms. There are eight inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ba(1), one Cu(4), and two equivalent Cu(3) atoms to form OBa2Cu3 trigonal bipyramids that share  a cornercorner with one O(8)Ba4Cu2 octahedra, corners with four equivalent O(7)Ba4MgCu octahedra, corners with four equivalent O(1)Ba2Cu3 trigonal bipyramids, edges with two equivalent O(2)Ba2Cu3 trigonal bipyramids, and faces with two equivalent O(7)Ba4MgCu octahedra. The corner-sharing octahedral tilt angles range from 0-58°. In the second O site, O(2) is bonded to two equivalent Ba(2), one Cu(3), and two equivalent Cu(4) atoms to form distorted OBa2Cu3 trigonal bipyramids that share  a cornercorner with one O(7)Ba4MgCu octahedra, corners with two equivalent O(4)Ba2Pr2Cu2 octahedra, corners with four equivalent O(8)Ba4Cu2 octahedra, corners with four equivalent O(2)Ba2Cu3 trigonal bipyramids,  an edgeedge with one O(4)Ba2Pr2Cu2 octahedra, edges with two equivalent O(1)Ba2Cu3 trigonal bipyramids, and faces with two equivalent O(8)Ba4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 1-64°. In the third O site, O(3) is bonded to one Mg(1), two equivalent Pr(1), and two equivalent Cu(1) atoms to form OPr2MgCu2 trigonal bipyramids that share  a cornercorner with one O(7)Ba4MgCu octahedra, corners with two equivalent O(4)Ba2Pr2Cu2 octahedra, corners with four equivalent O(3)Pr2MgCu2 trigonal bipyramids, and  an edgeedge with one O(4)Ba2Pr2Cu2 octahedra. The corner-sharing octahedral tilt angles range from 3-23°. In the fourth O site, O(4) is bonded to two equivalent Ba(2), two equivalent Pr(1), and two equivalent Cu(2) atoms to form distorted OBa2Pr2Cu2 octahedra that share corners with two equivalent O(4)Ba2Pr2Cu2 octahedra, corners with four equivalent O(8)Ba4Cu2 octahedra, corners with two equivalent O(2)Ba2Cu3 trigonal bipyramids, corners with two equivalent O(3)Pr2MgCu2 trigonal bipyramids, edges with two equivalent O(4)Ba2Pr2Cu2 octahedra,  an edgeedge with one O(2)Ba2Cu3 trigonal bipyramid,  an edgeedge with one O(3)Pr2MgCu2 trigonal bipyramid, and faces with two equivalent O(8)Ba4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 7-61°. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to one Ba(1), two equivalent Mg(1), and two equivalent Cu(1) atoms. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to two equivalent Ba(2), two equivalent Pr(1), and two equivalent Cu(2) atoms. In the seventh O site, O(7) is bonded to four equivalent Ba(1), one Mg(1), and one Cu(3) atom to form distorted OBa4MgCu octahedra that share corners with four equivalent O(7)Ba4MgCu octahedra,  a cornercorner with one O(2)Ba2Cu3 trigonal bipyramid,  a cornercorner with one O(3)Pr2MgCu2 trigonal bipyramid, corners with four equivalent O(1)Ba2Cu3 trigonal bipyramids, edges with four equivalent O(7)Ba4MgCu octahedra, and faces with two equivalent O(1)Ba2Cu3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 9°. In the eighth O site, O(8) is bonded to four equivalent Ba(2), one Cu(2), and one Cu(4) atom to form distorted OBa4Cu2 octahedra that share corners with four equivalent O(4)Ba2Pr2Cu2 octahedra, corners with four equivalent O(8)Ba4Cu2 octahedra,  a cornercorner with one O(1)Ba2Cu3 trigonal bipyramid, corners with four equivalent O(2)Ba2Cu3 trigonal bipyramids, edges with four equivalent O(8)Ba4Cu2 octahedra, faces with two equivalent O(4)Ba2Pr2Cu2 octahedra, and faces with two equivalent O(2)Ba2Cu3 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 5-61°.
Ba2MgPr(CuO2)4 crystallizes in the monoclinic Pm space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 7-coordinate geometry to one O(5), two equivalent O(1), and four equivalent O(7) atoms. The Ba(1)-O(5) bond length is 2.63 Å. Both Ba(1)-O(1) bond lengths are 2.69 Å. There are two shorter (2.77 Å) and two longer (2.86 Å) Ba(1)-O(7) bond lengths. In the second Ba site, Ba(2) is bonded in a 10-coordinate geometry to two equivalent O(2), two equivalent O(4), two equivalent O(6), and four equivalent O(8) atoms. Both Ba(2)-O(2) bond lengths are 2.87 Å. Both Ba(2)-O(4) bond lengths are 2.96 Å. Both Ba(2)-O(6) bond lengths are 3.26 Å. All Ba(2)-O(8) bond lengths are 2.81 Å. Mg(1) is bonded in a distorted see-saw-like geometry to one O(3), one O(7), and two equivalent O(5) atoms. The Mg(1)-O(3) bond length is 2.03 Å. The Mg(1)-O(7) bond length is 1.97 Å. Both Mg(1)-O(5) bond lengths are 2.14 Å. Pr(1) is bonded in a 6-coordinate geometry to two equivalent O(3), two equivalent O(4), and two equivalent O(6) atoms. Both Pr(1)-O(3) bond lengths are 2.47 Å. Both Pr(1)-O(4) bond lengths are 2.46 Å. Both Pr(1)-O(6) bond lengths are 2.36 Å. There are four inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a distorted linear geometry to two equivalent O(3) and two equivalent O(5) atoms. There is one shorter (1.93 Å) and one longer (2.14 Å) Cu(1)-O(3) bond length. Both Cu(1)-O(5) bond lengths are 2.62 Å. In the second Cu site, Cu(2) is bonded to one O(8), two equivalent O(4), and two equivalent O(6) atoms to form corner-sharing CuO5 trigonal bipyramids. The Cu(2)-O(8) bond length is 2.24 Å. Both Cu(2)-O(4) bond lengths are 2.03 Å. Both Cu(2)-O(6) bond lengths are 1.99 Å. In the third Cu site, Cu(3) is bonded in a square co-planar geometry to one O(2), one O(7), and two equivalent O(1) atoms. The Cu(3)-O(2) bond length is 1.88 Å. The Cu(3)-O(7) bond length is 1.94 Å. There is one shorter (2.03 Å) and one longer (2.04 Å) Cu(3)-O(1) bond length. In the fourth Cu site, Cu(4) is bonded in a square co-planar geometry to one O(1), one O(8), and two equivalent O(2) atoms. The Cu(4)-O(1) bond length is 1.88 Å. The Cu(4)-O(8) bond length is 1.85 Å. There is one shorter (2.03 Å) and one longer (2.04 Å) Cu(4)-O(2) bond length. There are eight inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ba(1), one Cu(4), and two equivalent Cu(3) atoms to form OBa2Cu3 trigonal bipyramids that share  a cornercorner with one O(8)Ba4Cu2 octahedra, corners with four equivalent O(7)Ba4MgCu octahedra, corners with four equivalent O(1)Ba2Cu3 trigonal bipyramids, edges with two equivalent O(2)Ba2Cu3 trigonal bipyramids, and faces with two equivalent O(7)Ba4MgCu octahedra. The corner-sharing octahedral tilt angles range from 0-58°. In the second O site, O(2) is bonded to two equivalent Ba(2), one Cu(3), and two equivalent Cu(4) atoms to form distorted OBa2Cu3 trigonal bipyramids that share  a cornercorner with one O(7)Ba4MgCu octahedra, corners with two equivalent O(4)Ba2Pr2Cu2 octahedra, corners with four equivalent O(8)Ba4Cu2 octahedra, corners with four equivalent O(2)Ba2Cu3 trigonal bipyramids,  an edgeedge with one O(4)Ba2Pr2Cu2 octahedra, edges with two equivalent O(1)Ba2Cu3 trigonal bipyramids, and faces with two equivalent O(8)Ba4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 1-64°. In the third O site, O(3) is bonded to one Mg(1), two equivalent Pr(1), and two equivalent Cu(1) atoms to form OPr2MgCu2 trigonal bipyramids that share  a cornercorner with one O(7)Ba4MgCu octahedra, corners with two equivalent O(4)Ba2Pr2Cu2 octahedra, corners with four equivalent O(3)Pr2MgCu2 trigonal bipyramids, and  an edgeedge with one O(4)Ba2Pr2Cu2 octahedra. The corner-sharing octahedral tilt angles range from 3-23°. In the fourth O site, O(4) is bonded to two equivalent Ba(2), two equivalent Pr(1), and two equivalent Cu(2) atoms to form distorted OBa2Pr2Cu2 octahedra that share corners with two equivalent O(4)Ba2Pr2Cu2 octahedra, corners with four equivalent O(8)Ba4Cu2 octahedra, corners with two equivalent O(2)Ba2Cu3 trigonal bipyramids, corners with two equivalent O(3)Pr2MgCu2 trigonal bipyramids, edges with two equivalent O(4)Ba2Pr2Cu2 octahedra,  an edgeedge with one O(2)Ba2Cu3 trigonal bipyramid,  an edgeedge with one O(3)Pr2MgCu2 trigonal bipyramid, and faces with two equivalent O(8)Ba4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 7-61°. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to one Ba(1), two equivalent Mg(1), and two equivalent Cu(1) atoms. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to two equivalent Ba(2), two equivalent Pr(1), and two equivalent Cu(2) atoms. In the seventh O site, O(7) is bonded to four equivalent Ba(1), one Mg(1), and one Cu(3) atom to form distorted OBa4MgCu octahedra that share corners with four equivalent O(7)Ba4MgCu octahedra,  a cornercorner with one O(2)Ba2Cu3 trigonal bipyramid,  a cornercorner with one O(3)Pr2MgCu2 trigonal bipyramid, corners with four equivalent O(1)Ba2Cu3 trigonal bipyramids, edges with four equivalent O(7)Ba4MgCu octahedra, and faces with two equivalent O(1)Ba2Cu3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 9°. In the eighth O site, O(8) is bonded to four equivalent Ba(2), one Cu(2), and one Cu(4) atom to form distorted OBa4Cu2 octahedra that share corners with four equivalent O(4)Ba2Pr2Cu2 octahedra, corners with four equivalent O(8)Ba4Cu2 octahedra,  a cornercorner with one O(1)Ba2Cu3 trigonal bipyramid, corners with four equivalent O(2)Ba2Cu3 trigonal bipyramids, edges with four equivalent O(8)Ba4Cu2 octahedra, faces with two equivalent O(4)Ba2Pr2Cu2 octahedra, and faces with two equivalent O(2)Ba2Cu3 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 5-61°.