Pb2V3O9 crystallizes in the monoclinic Cc space group. There are three inequivalent V sites. In the first V site, V(1) is bonded to one O(1), one O(2), one O(7), one O(9), and two equivalent O(3) atoms to form distorted VO6 octahedra that share corners with two equivalent V(1)O6 octahedra, corners with two equivalent V(2)O4 tetrahedra, and corners with two equivalent V(3)O4 tetrahedra. The corner-sharing octahedral tilt angles are 35°. In the second V site, V(2) is bonded to one O(4), one O(7), one O(8), and one O(9) atom to form corner-sharing VO4 tetrahedra. The corner-sharing octahedral tilt angles range from 51-56°. In the third V site, V(3) is bonded to one O(1), one O(2), one O(5), and one O(6) atom to form corner-sharing VO4 tetrahedra. The corner-sharing octahedral tilt angles range from 34-43°. There are two inequivalent Pb sites. In the first Pb site, Pb(1) is bonded in a 8-coordinate geometry to one O(3), one O(4), one O(7), one O(8), two equivalent O(5), and two equivalent O(6) atoms. In the second Pb site, Pb(2) is bonded in a 6-coordinate geometry to one O(4), one O(5), one O(6), one O(7), one O(8), and one O(9) atom. There are nine inequivalent O sites. In the first O site, O(7) is bonded in a 2-coordinate geometry to one V(1), one V(2), one Pb(1), and one Pb(2) atom. In the second O site, O(8) is bonded in a single-bond geometry to one V(2), one Pb(1), and one Pb(2) atom. In the third O site, O(9) is bonded in a distorted bent 120 degrees geometry to one V(1), one V(2), and one Pb(2) atom. In the fourth O site, O(1) is bonded in a bent 150 degrees geometry to one V(1) and one V(3) atom. In the fifth O site, O(2) is bonded in a distorted bent 150 degrees geometry to one V(1) and one V(3) atom. In the sixth O site, O(3) is bonded in a distorted bent 150 degrees geometry to two equivalent V(1) and one Pb(1) atom. In the seventh O site, O(4) is bonded in a single-bond geometry to one V(2), one Pb(1), and one Pb(2) atom. In the eighth O site, O(5) is bonded in a distorted single-bond geometry to one V(3), one Pb(2), and two equivalent Pb(1) atoms. In the ninth O site, O(6) is bonded in a distorted single-bond geometry to one V(3), one Pb(2), and two equivalent Pb(1) atoms.
Pb2V3O9 crystallizes in the monoclinic Cc space group. There are three inequivalent V sites. In the first V site, V(1) is bonded to one O(1), one O(2), one O(7), one O(9), and two equivalent O(3) atoms to form distorted VO6 octahedra that share corners with two equivalent V(1)O6 octahedra, corners with two equivalent V(2)O4 tetrahedra, and corners with two equivalent V(3)O4 tetrahedra. The corner-sharing octahedral tilt angles are 35°. The V(1)-O(1) bond length is 2.01 Å. The V(1)-O(2) bond length is 2.02 Å. The V(1)-O(7) bond length is 2.01 Å. The V(1)-O(9) bond length is 2.02 Å. There is one shorter (1.71 Å) and one longer (2.20 Å) V(1)-O(3) bond length. In the second V site, V(2) is bonded to one O(4), one O(7), one O(8), and one O(9) atom to form corner-sharing VO4 tetrahedra. The corner-sharing octahedral tilt angles range from 51-56°. The V(2)-O(4) bond length is 1.71 Å. The V(2)-O(7) bond length is 1.80 Å. The V(2)-O(8) bond length is 1.70 Å. The V(2)-O(9) bond length is 1.79 Å. In the third V site, V(3) is bonded to one O(1), one O(2), one O(5), and one O(6) atom to form corner-sharing VO4 tetrahedra. The corner-sharing octahedral tilt angles range from 34-43°. The V(3)-O(1) bond length is 1.76 Å. The V(3)-O(2) bond length is 1.75 Å. The V(3)-O(5) bond length is 1.74 Å. The V(3)-O(6) bond length is 1.74 Å. There are two inequivalent Pb sites. In the first Pb site, Pb(1) is bonded in a 8-coordinate geometry to one O(3), one O(4), one O(7), one O(8), two equivalent O(5), and two equivalent O(6) atoms. The Pb(1)-O(3) bond length is 2.79 Å. The Pb(1)-O(4) bond length is 2.70 Å. The Pb(1)-O(7) bond length is 2.83 Å. The Pb(1)-O(8) bond length is 2.75 Å. There is one shorter (2.74 Å) and one longer (2.78 Å) Pb(1)-O(5) bond length. There is one shorter (2.64 Å) and one longer (2.75 Å) Pb(1)-O(6) bond length. In the second Pb site, Pb(2) is bonded in a 6-coordinate geometry to one O(4), one O(5), one O(6), one O(7), one O(8), and one O(9) atom. The Pb(2)-O(4) bond length is 2.65 Å. The Pb(2)-O(5) bond length is 2.60 Å. The Pb(2)-O(6) bond length is 2.66 Å. The Pb(2)-O(7) bond length is 2.60 Å. The Pb(2)-O(8) bond length is 2.74 Å. The Pb(2)-O(9) bond length is 2.62 Å. There are nine inequivalent O sites. In the first O site, O(7) is bonded in a 2-coordinate geometry to one V(1), one V(2), one Pb(1), and one Pb(2) atom. In the second O site, O(8) is bonded in a single-bond geometry to one V(2), one Pb(1), and one Pb(2) atom. In the third O site, O(9) is bonded in a distorted bent 120 degrees geometry to one V(1), one V(2), and one Pb(2) atom. In the fourth O site, O(1) is bonded in a bent 150 degrees geometry to one V(1) and one V(3) atom. In the fifth O site, O(2) is bonded in a distorted bent 150 degrees geometry to one V(1) and one V(3) atom. In the sixth O site, O(3) is bonded in a distorted bent 150 degrees geometry to two equivalent V(1) and one Pb(1) atom. In the seventh O site, O(4) is bonded in a single-bond geometry to one V(2), one Pb(1), and one Pb(2) atom. In the eighth O site, O(5) is bonded in a distorted single-bond geometry to one V(3), one Pb(2), and two equivalent Pb(1) atoms. In the ninth O site, O(6) is bonded in a distorted single-bond geometry to one V(3), one Pb(2), and two equivalent Pb(1) atoms.