Rb3NaPbO4 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 5-coordinate geometry to one O(2), one O(3), one O(4), and two equivalent O(1) atoms. In the second Rb site, Rb(2) is bonded in a 5-coordinate geometry to one O(4), two equivalent O(2), and two equivalent O(3) atoms. In the third Rb site, Rb(3) is bonded in a 5-coordinate geometry to one O(3), one O(4), and three equivalent O(1) atoms. Na(1) is bonded to one O(3), one O(4), and two equivalent O(2) atoms to form NaO4 tetrahedra that share corners with four equivalent Pb(1)O4 tetrahedra and  an edgeedge with one Na(1)O4 tetrahedra. Pb(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PbO4 tetrahedra that share corners with four equivalent Na(1)O4 tetrahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Rb(1), three equivalent Rb(3), and one Pb(1) atom to form ORb5Pb octahedra that share corners with two equivalent O(3)Rb4NaPb octahedra, corners with four equivalent O(1)Rb5Pb octahedra, edges with two equivalent O(3)Rb4NaPb octahedra, and edges with two equivalent O(1)Rb5Pb octahedra. The corner-sharing octahedral tilt angles range from 18-71°. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Rb(1), two equivalent Rb(2), two equivalent Na(1), and one Pb(1) atom. In the third O site, O(3) is bonded to one Rb(1), one Rb(3), two equivalent Rb(2), one Na(1), and one Pb(1) atom to form distorted ORb4NaPb octahedra that share corners with two equivalent O(3)Rb4NaPb octahedra, corners with two equivalent O(1)Rb5Pb octahedra, and edges with two equivalent O(1)Rb5Pb octahedra. The corner-sharing octahedral tilt angles range from 18-71°. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to one Rb(1), one Rb(2), one Rb(3), one Na(1), and one Pb(1) atom.
Rb3NaPbO4 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 5-coordinate geometry to one O(2), one O(3), one O(4), and two equivalent O(1) atoms. The Rb(1)-O(2) bond length is 3.21 Å. The Rb(1)-O(3) bond length is 2.90 Å. The Rb(1)-O(4) bond length is 2.90 Å. There is one shorter (2.77 Å) and one longer (3.02 Å) Rb(1)-O(1) bond length. In the second Rb site, Rb(2) is bonded in a 5-coordinate geometry to one O(4), two equivalent O(2), and two equivalent O(3) atoms. The Rb(2)-O(4) bond length is 3.00 Å. There is one shorter (3.02 Å) and one longer (3.14 Å) Rb(2)-O(2) bond length. There is one shorter (2.93 Å) and one longer (3.00 Å) Rb(2)-O(3) bond length. In the third Rb site, Rb(3) is bonded in a 5-coordinate geometry to one O(3), one O(4), and three equivalent O(1) atoms. The Rb(3)-O(3) bond length is 2.89 Å. The Rb(3)-O(4) bond length is 3.32 Å. There are a spread of Rb(3)-O(1) bond distances ranging from 2.95-3.05 Å. Na(1) is bonded to one O(3), one O(4), and two equivalent O(2) atoms to form NaO4 tetrahedra that share corners with four equivalent Pb(1)O4 tetrahedra and  an edgeedge with one Na(1)O4 tetrahedra. The Na(1)-O(3) bond length is 2.30 Å. The Na(1)-O(4) bond length is 2.35 Å. There is one shorter (2.36 Å) and one longer (2.40 Å) Na(1)-O(2) bond length. Pb(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PbO4 tetrahedra that share corners with four equivalent Na(1)O4 tetrahedra. The Pb(1)-O(1) bond length is 2.11 Å. The Pb(1)-O(2) bond length is 2.12 Å. The Pb(1)-O(3) bond length is 2.11 Å. The Pb(1)-O(4) bond length is 2.11 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Rb(1), three equivalent Rb(3), and one Pb(1) atom to form ORb5Pb octahedra that share corners with two equivalent O(3)Rb4NaPb octahedra, corners with four equivalent O(1)Rb5Pb octahedra, edges with two equivalent O(3)Rb4NaPb octahedra, and edges with two equivalent O(1)Rb5Pb octahedra. The corner-sharing octahedral tilt angles range from 18-71°. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Rb(1), two equivalent Rb(2), two equivalent Na(1), and one Pb(1) atom. In the third O site, O(3) is bonded to one Rb(1), one Rb(3), two equivalent Rb(2), one Na(1), and one Pb(1) atom to form distorted ORb4NaPb octahedra that share corners with two equivalent O(3)Rb4NaPb octahedra, corners with two equivalent O(1)Rb5Pb octahedra, and edges with two equivalent O(1)Rb5Pb octahedra. The corner-sharing octahedral tilt angles range from 18-71°. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to one Rb(1), one Rb(2), one Rb(3), one Na(1), and one Pb(1) atom.