Sr2FeCu(PbO3)2 crystallizes in the monoclinic P2/m space group. Sr(1) is bonded in a 9-coordinate geometry to one O(4), two equivalent O(2), two equivalent O(3), and four equivalent O(1) atoms. Fe(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form corner-sharing FeO6 octahedra. The corner-sharing octahedra are not tilted. Cu(1) is bonded in a linear geometry to two equivalent O(4) atoms. Pb(1) is bonded in a 3-coordinate geometry to one O(1) and two equivalent O(4) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Sr(1), one Fe(1), and one Pb(1) atom to form distorted OSr4FePb octahedra that share corners with four equivalent O(2)Sr4Fe2 octahedra, corners with four equivalent O(3)Sr4Fe2 octahedra, corners with five equivalent O(1)Sr4FePb octahedra, edges with four equivalent O(1)Sr4FePb octahedra, faces with two equivalent O(2)Sr4Fe2 octahedra, and faces with two equivalent O(3)Sr4Fe2 octahedra. The corner-sharing octahedral tilt angles range from 0-52°. In the second O site, O(2) is bonded to four equivalent Sr(1) and two equivalent Fe(1) atoms to form distorted OSr4Fe2 octahedra that share corners with two equivalent O(2)Sr4Fe2 octahedra, corners with eight equivalent O(1)Sr4FePb octahedra, edges with two equivalent O(2)Sr4Fe2 octahedra, faces with four equivalent O(3)Sr4Fe2 octahedra, and faces with four equivalent O(1)Sr4FePb octahedra. The corner-sharing octahedral tilt angles range from 0-51°. In the third O site, O(3) is bonded to four equivalent Sr(1) and two equivalent Fe(1) atoms to form OSr4Fe2 octahedra that share corners with two equivalent O(3)Sr4Fe2 octahedra, corners with eight equivalent O(1)Sr4FePb octahedra, edges with two equivalent O(3)Sr4Fe2 octahedra, faces with four equivalent O(2)Sr4Fe2 octahedra, and faces with four equivalent O(1)Sr4FePb octahedra. The corner-sharing octahedral tilt angles range from 0-52°. In the fourth O site, O(4) is bonded in a distorted see-saw-like geometry to one Sr(1), one Cu(1), and two equivalent Pb(1) atoms.
Sr2FeCu(PbO3)2 crystallizes in the monoclinic P2/m space group. Sr(1) is bonded in a 9-coordinate geometry to one O(4), two equivalent O(2), two equivalent O(3), and four equivalent O(1) atoms. The Sr(1)-O(4) bond length is 2.64 Å. There is one shorter (2.64 Å) and one longer (2.67 Å) Sr(1)-O(2) bond length. Both Sr(1)-O(3) bond lengths are 2.63 Å. There are two shorter (2.82 Å) and two longer (2.84 Å) Sr(1)-O(1) bond lengths. Fe(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form corner-sharing FeO6 octahedra. The corner-sharing octahedra are not tilted. Both Fe(1)-O(1) bond lengths are 2.19 Å. Both Fe(1)-O(2) bond lengths are 1.96 Å. Both Fe(1)-O(3) bond lengths are 1.99 Å. Cu(1) is bonded in a linear geometry to two equivalent O(4) atoms. Both Cu(1)-O(4) bond lengths are 1.85 Å. Pb(1) is bonded in a 3-coordinate geometry to one O(1) and two equivalent O(4) atoms. The Pb(1)-O(1) bond length is 2.19 Å. Both Pb(1)-O(4) bond lengths are 2.47 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Sr(1), one Fe(1), and one Pb(1) atom to form distorted OSr4FePb octahedra that share corners with four equivalent O(2)Sr4Fe2 octahedra, corners with four equivalent O(3)Sr4Fe2 octahedra, corners with five equivalent O(1)Sr4FePb octahedra, edges with four equivalent O(1)Sr4FePb octahedra, faces with two equivalent O(2)Sr4Fe2 octahedra, and faces with two equivalent O(3)Sr4Fe2 octahedra. The corner-sharing octahedral tilt angles range from 0-52°. In the second O site, O(2) is bonded to four equivalent Sr(1) and two equivalent Fe(1) atoms to form distorted OSr4Fe2 octahedra that share corners with two equivalent O(2)Sr4Fe2 octahedra, corners with eight equivalent O(1)Sr4FePb octahedra, edges with two equivalent O(2)Sr4Fe2 octahedra, faces with four equivalent O(3)Sr4Fe2 octahedra, and faces with four equivalent O(1)Sr4FePb octahedra. The corner-sharing octahedral tilt angles range from 0-51°. In the third O site, O(3) is bonded to four equivalent Sr(1) and two equivalent Fe(1) atoms to form OSr4Fe2 octahedra that share corners with two equivalent O(3)Sr4Fe2 octahedra, corners with eight equivalent O(1)Sr4FePb octahedra, edges with two equivalent O(3)Sr4Fe2 octahedra, faces with four equivalent O(2)Sr4Fe2 octahedra, and faces with four equivalent O(1)Sr4FePb octahedra. The corner-sharing octahedral tilt angles range from 0-52°. In the fourth O site, O(4) is bonded in a distorted see-saw-like geometry to one Sr(1), one Cu(1), and two equivalent Pb(1) atoms.