Pb3Nb4O13 crystallizes in the trigonal R3m space group. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to three equivalent O(1) and three equivalent O(3) atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 35-47°. In the second Nb site, Nb(2) is bonded to one O(1), one O(3), two equivalent O(2), and two equivalent O(4) atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 31-47°. Pb(1) is bonded in a 4-coordinate geometry to one O(4), one O(5), and two equivalent O(1) atoms. There are five inequivalent O sites. In the first O site, O(5) is bonded in a trigonal non-coplanar geometry to three equivalent Pb(1) atoms. In the second O site, O(1) is bonded in a 4-coordinate geometry to one Nb(1), one Nb(2), and two equivalent Pb(1) atoms. In the third O site, O(2) is bonded in a bent 150 degrees geometry to two equivalent Nb(2) atoms. In the fourth O site, O(3) is bonded in a bent 150 degrees geometry to one Nb(1) and one Nb(2) atom. In the fifth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Nb(2) and one Pb(1) atom.
Pb3Nb4O13 crystallizes in the trigonal R3m space group. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to three equivalent O(1) and three equivalent O(3) atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 35-47°. All Nb(1)-O(1) bond lengths are 1.94 Å. All Nb(1)-O(3) bond lengths are 2.07 Å. In the second Nb site, Nb(2) is bonded to one O(1), one O(3), two equivalent O(2), and two equivalent O(4) atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 31-47°. The Nb(2)-O(1) bond length is 2.19 Å. The Nb(2)-O(3) bond length is 1.91 Å. Both Nb(2)-O(2) bond lengths are 1.97 Å. Both Nb(2)-O(4) bond lengths are 2.03 Å. Pb(1) is bonded in a 4-coordinate geometry to one O(4), one O(5), and two equivalent O(1) atoms. The Pb(1)-O(4) bond length is 2.41 Å. The Pb(1)-O(5) bond length is 2.19 Å. Both Pb(1)-O(1) bond lengths are 2.57 Å. There are five inequivalent O sites. In the first O site, O(5) is bonded in a trigonal non-coplanar geometry to three equivalent Pb(1) atoms. In the second O site, O(1) is bonded in a 4-coordinate geometry to one Nb(1), one Nb(2), and two equivalent Pb(1) atoms. In the third O site, O(2) is bonded in a bent 150 degrees geometry to two equivalent Nb(2) atoms. In the fourth O site, O(3) is bonded in a bent 150 degrees geometry to one Nb(1) and one Nb(2) atom. In the fifth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Nb(2) and one Pb(1) atom.