Cs4PbO3 crystallizes in the monoclinic P2_1 space group. There are eight inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a distorted see-saw-like geometry to one O(1), one O(2), one O(3), and one O(6) atom. In the second Cs site, Cs(2) is bonded in a 3-coordinate geometry to one O(2), one O(4), and one O(5) atom. In the third Cs site, Cs(3) is bonded in a 4-coordinate geometry to one O(1), one O(3), one O(4), and one O(6) atom. In the fourth Cs site, Cs(4) is bonded in a 4-coordinate geometry to one O(1), one O(4), and two equivalent O(5) atoms. In the fifth Cs site, Cs(5) is bonded in a 2-coordinate geometry to one O(1), one O(5), and two equivalent O(2) atoms. In the sixth Cs site, Cs(6) is bonded in a 4-coordinate geometry to one O(2), one O(3), and two equivalent O(6) atoms. In the seventh Cs site, Cs(7) is bonded in a distorted rectangular see-saw-like geometry to one O(1), one O(3), one O(4), and one O(6) atom. In the eighth Cs site, Cs(8) is bonded in a 3-coordinate geometry to one O(1), one O(4), and one O(5) atom. There are two inequivalent Pb sites. In the first Pb site, Pb(1) is bonded in a distorted trigonal non-coplanar geometry to one O(1), one O(2), and one O(3) atom. In the second Pb site, Pb(2) is bonded in a distorted trigonal non-coplanar geometry to one O(4), one O(5), and one O(6) atom. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 7-coordinate geometry to one Cs(1), one Cs(3), one Cs(4), one Cs(5), one Cs(7), one Cs(8), and one Pb(1) atom. In the second O site, O(2) is bonded to one Cs(1), one Cs(2), one Cs(6), two equivalent Cs(5), and one Pb(1) atom to form distorted OCs5Pb octahedra that share corners with two equivalent O(2)Cs5Pb octahedra,  a cornercorner with one O(3)Cs4Pb square pyramid, and  an edgeedge with one O(3)Cs4Pb square pyramid. The corner-sharing octahedral tilt angles are 42°. In the third O site, O(3) is bonded to one Cs(1), one Cs(3), one Cs(6), one Cs(7), and one Pb(1) atom to form a mixture of distorted corner and edge-sharing OCs4Pb square pyramids. The corner-sharing octahedral tilt angles are 18°. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one Cs(2), one Cs(3), one Cs(4), one Cs(7), one Cs(8), and one Pb(2) atom. In the fifth O site, O(5) is bonded in a 6-coordinate geometry to one Cs(2), one Cs(5), one Cs(8), two equivalent Cs(4), and one Pb(2) atom. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to one Cs(1), one Cs(3), one Cs(7), two equivalent Cs(6), and one Pb(2) atom.
Cs4PbO3 crystallizes in the monoclinic P2_1 space group. There are eight inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a distorted see-saw-like geometry to one O(1), one O(2), one O(3), and one O(6) atom. The Cs(1)-O(1) bond length is 3.14 Å. The Cs(1)-O(2) bond length is 3.09 Å. The Cs(1)-O(3) bond length is 3.12 Å. The Cs(1)-O(6) bond length is 2.86 Å. In the second Cs site, Cs(2) is bonded in a 3-coordinate geometry to one O(2), one O(4), and one O(5) atom. The Cs(2)-O(2) bond length is 2.88 Å. The Cs(2)-O(4) bond length is 3.19 Å. The Cs(2)-O(5) bond length is 2.85 Å. In the third Cs site, Cs(3) is bonded in a 4-coordinate geometry to one O(1), one O(3), one O(4), and one O(6) atom. The Cs(3)-O(1) bond length is 3.06 Å. The Cs(3)-O(3) bond length is 2.92 Å. The Cs(3)-O(4) bond length is 3.13 Å. The Cs(3)-O(6) bond length is 3.00 Å. In the fourth Cs site, Cs(4) is bonded in a 4-coordinate geometry to one O(1), one O(4), and two equivalent O(5) atoms. The Cs(4)-O(1) bond length is 3.35 Å. The Cs(4)-O(4) bond length is 3.11 Å. There is one shorter (2.98 Å) and one longer (2.99 Å) Cs(4)-O(5) bond length. In the fifth Cs site, Cs(5) is bonded in a 2-coordinate geometry to one O(1), one O(5), and two equivalent O(2) atoms. The Cs(5)-O(1) bond length is 3.52 Å. The Cs(5)-O(5) bond length is 3.38 Å. There is one shorter (3.03 Å) and one longer (3.17 Å) Cs(5)-O(2) bond length. In the sixth Cs site, Cs(6) is bonded in a 4-coordinate geometry to one O(2), one O(3), and two equivalent O(6) atoms. The Cs(6)-O(2) bond length is 2.93 Å. The Cs(6)-O(3) bond length is 2.92 Å. There is one shorter (3.35 Å) and one longer (3.43 Å) Cs(6)-O(6) bond length. In the seventh Cs site, Cs(7) is bonded in a distorted rectangular see-saw-like geometry to one O(1), one O(3), one O(4), and one O(6) atom. The Cs(7)-O(1) bond length is 3.22 Å. The Cs(7)-O(3) bond length is 2.87 Å. The Cs(7)-O(4) bond length is 2.93 Å. The Cs(7)-O(6) bond length is 2.96 Å. In the eighth Cs site, Cs(8) is bonded in a 3-coordinate geometry to one O(1), one O(4), and one O(5) atom. The Cs(8)-O(1) bond length is 2.76 Å. The Cs(8)-O(4) bond length is 2.88 Å. The Cs(8)-O(5) bond length is 2.99 Å. There are two inequivalent Pb sites. In the first Pb site, Pb(1) is bonded in a distorted trigonal non-coplanar geometry to one O(1), one O(2), and one O(3) atom. The Pb(1)-O(1) bond length is 2.18 Å. The Pb(1)-O(2) bond length is 2.20 Å. The Pb(1)-O(3) bond length is 2.17 Å. In the second Pb site, Pb(2) is bonded in a distorted trigonal non-coplanar geometry to one O(4), one O(5), and one O(6) atom. The Pb(2)-O(4) bond length is 2.19 Å. The Pb(2)-O(5) bond length is 2.22 Å. The Pb(2)-O(6) bond length is 2.18 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 7-coordinate geometry to one Cs(1), one Cs(3), one Cs(4), one Cs(5), one Cs(7), one Cs(8), and one Pb(1) atom. In the second O site, O(2) is bonded to one Cs(1), one Cs(2), one Cs(6), two equivalent Cs(5), and one Pb(1) atom to form distorted OCs5Pb octahedra that share corners with two equivalent O(2)Cs5Pb octahedra,  a cornercorner with one O(3)Cs4Pb square pyramid, and  an edgeedge with one O(3)Cs4Pb square pyramid. The corner-sharing octahedral tilt angles are 42°. In the third O site, O(3) is bonded to one Cs(1), one Cs(3), one Cs(6), one Cs(7), and one Pb(1) atom to form a mixture of distorted corner and edge-sharing OCs4Pb square pyramids. The corner-sharing octahedral tilt angles are 18°. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one Cs(2), one Cs(3), one Cs(4), one Cs(7), one Cs(8), and one Pb(2) atom. In the fifth O site, O(5) is bonded in a 6-coordinate geometry to one Cs(2), one Cs(5), one Cs(8), two equivalent Cs(4), and one Pb(2) atom. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to one Cs(1), one Cs(3), one Cs(7), two equivalent Cs(6), and one Pb(2) atom.