Pb3MgNb2O9 is Pb (Zr_0.50 Ti_0.48) O_3-derived structured and crystallizes in the monoclinic Cm space group. Mg(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(5) atoms to form MgO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra and corners with four equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 12-18°. Nb(1) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms to form distorted NbO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra and corners with four equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 2-21°. There are two inequivalent Pb sites. In the first Pb site, Pb(1) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(3), and one O(5) atom. In the second Pb site, Pb(2) is bonded in a 3-coordinate geometry to one O(5) and two equivalent O(2) atoms. There are five inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Mg(1), one Nb(1), and one Pb(1) atom. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Nb(1), one Pb(1), and one Pb(2) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to two equivalent Nb(1) and one Pb(1) atom. In the fourth O site, O(4) is bonded in a distorted linear geometry to two equivalent Nb(1) atoms. In the fifth O site, O(5) is bonded to two equivalent Mg(1), one Pb(2), and two equivalent Pb(1) atoms to form distorted corner-sharing OMg2Pb3 square pyramids.
Pb3MgNb2O9 is Pb (Zr_0.50 Ti_0.48) O_3-derived structured and crystallizes in the monoclinic Cm space group. Mg(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(5) atoms to form MgO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra and corners with four equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 12-18°. Both Mg(1)-O(1) bond lengths are 2.11 Å. Both Mg(1)-O(2) bond lengths are 2.18 Å. There is one shorter (2.05 Å) and one longer (2.26 Å) Mg(1)-O(5) bond length. Nb(1) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms to form distorted NbO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra and corners with four equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 2-21°. The Nb(1)-O(1) bond length is 1.98 Å. The Nb(1)-O(2) bond length is 2.01 Å. There is one shorter (2.01 Å) and one longer (2.06 Å) Nb(1)-O(3) bond length. There is one shorter (1.86 Å) and one longer (2.43 Å) Nb(1)-O(4) bond length. There are two inequivalent Pb sites. In the first Pb site, Pb(1) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(3), and one O(5) atom. The Pb(1)-O(1) bond length is 2.39 Å. The Pb(1)-O(2) bond length is 2.47 Å. The Pb(1)-O(3) bond length is 2.75 Å. The Pb(1)-O(5) bond length is 2.51 Å. In the second Pb site, Pb(2) is bonded in a 3-coordinate geometry to one O(5) and two equivalent O(2) atoms. The Pb(2)-O(5) bond length is 2.41 Å. Both Pb(2)-O(2) bond lengths are 2.42 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Mg(1), one Nb(1), and one Pb(1) atom. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Nb(1), one Pb(1), and one Pb(2) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to two equivalent Nb(1) and one Pb(1) atom. In the fourth O site, O(4) is bonded in a distorted linear geometry to two equivalent Nb(1) atoms. In the fifth O site, O(5) is bonded to two equivalent Mg(1), one Pb(2), and two equivalent Pb(1) atoms to form distorted corner-sharing OMg2Pb3 square pyramids.