KPbO2 crystallizes in the triclinic P-1 space group. There are four inequivalent K sites. In the first K site, K(1) is bonded in a 6-coordinate geometry to one O(2), one O(4), one O(5), one O(6), one O(7), and one O(8) atom. In the second K site, K(2) is bonded to one O(3), one O(6), two equivalent O(2), and two equivalent O(7) atoms to form distorted KO6 octahedra that share corners with three equivalent Pb(4)O6 octahedra,  an edgeedge with one Pb(4)O6 octahedra, edges with two equivalent K(2)O6 octahedra, and edges with two equivalent Pb(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-17°. In the third K site, K(3) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom. In the fourth K site, K(4) is bonded to one O(5), one O(8), two equivalent O(1), and two equivalent O(4) atoms to form distorted KO6 octahedra that share corners with three equivalent Pb(3)O6 octahedra,  an edgeedge with one Pb(3)O6 octahedra, edges with two equivalent K(4)O6 octahedra, and edges with two equivalent Pb(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-16°. There are four inequivalent Pb sites. In the first Pb site, Pb(1) is bonded in a 3-coordinate geometry to one O(4), one O(5), and one O(8) atom. In the second Pb site, Pb(2) is bonded in a 3-coordinate geometry to one O(2), one O(3), and one O(6) atom. In the third Pb site, Pb(3) is bonded to one O(1), one O(3), one O(4), one O(6), one O(7), and one O(8) atom to form PbO6 octahedra that share corners with three equivalent K(4)O6 octahedra,  an edgeedge with one K(4)O6 octahedra, edges with two equivalent K(2)O6 octahedra, and edges with two equivalent Pb(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-16°. In the fourth Pb site, Pb(4) is bonded to one O(1), one O(2), one O(3), one O(5), one O(7), and one O(8) atom to form PbO6 octahedra that share corners with three equivalent K(2)O6 octahedra,  an edgeedge with one K(2)O6 octahedra, edges with two equivalent K(4)O6 octahedra, and edges with two equivalent Pb(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-17°. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one K(3), two equivalent K(4), one Pb(3), and one Pb(4) atom to form OK3Pb2 square pyramids that share corners with two equivalent O(4)K4Pb2 octahedra, corners with two equivalent O(8)K2Pb3 square pyramids, corners with two equivalent O(5)K3Pb2 square pyramids, corners with three equivalent O(3)K2Pb3 square pyramids,  an edgeedge with one O(2)K4Pb2 octahedra, edges with two equivalent O(4)K4Pb2 octahedra,  an edgeedge with one O(8)K2Pb3 square pyramid,  an edgeedge with one O(1)K3Pb2 square pyramid,  an edgeedge with one O(5)K3Pb2 square pyramid,  an edgeedge with one O(6)K3Pb2 square pyramid, and  an edgeedge with one O(7)K3Pb2 square pyramid. The corner-sharing octahedral tilt angles range from 14-18°. In the second O site, O(2) is bonded to one K(1), one K(3), two equivalent K(2), one Pb(2), and one Pb(4) atom to form distorted OK4Pb2 octahedra that share  a cornercorner with one O(3)K2Pb3 square pyramid,  a cornercorner with one O(6)K3Pb2 square pyramid, corners with two equivalent O(7)K3Pb2 square pyramids, corners with three equivalent O(5)K3Pb2 square pyramids,  an edgeedge with one O(2)K4Pb2 octahedra,  an edgeedge with one O(4)K4Pb2 octahedra,  an edgeedge with one O(8)K2Pb3 square pyramid,  an edgeedge with one O(1)K3Pb2 square pyramid, edges with two equivalent O(3)K2Pb3 square pyramids, edges with two equivalent O(6)K3Pb2 square pyramids, and edges with two equivalent O(7)K3Pb2 square pyramids. In the third O site, O(3) is bonded to one K(2), one K(3), one Pb(2), one Pb(3), and one Pb(4) atom to form OK2Pb3 square pyramids that share  a cornercorner with one O(2)K4Pb2 octahedra, corners with two equivalent O(6)K3Pb2 square pyramids, corners with two equivalent O(7)K3Pb2 square pyramids, corners with three equivalent O(1)K3Pb2 square pyramids,  an edgeedge with one O(4)K4Pb2 octahedra, edges with two equivalent O(2)K4Pb2 octahedra,  an edgeedge with one O(8)K2Pb3 square pyramid,  an edgeedge with one O(5)K3Pb2 square pyramid,  an edgeedge with one O(6)K3Pb2 square pyramid, and  an edgeedge with one O(7)K3Pb2 square pyramid. The corner-sharing octahedral tilt angles are 85°. In the fourth O site, O(4) is bonded to one K(1), one K(3), two equivalent K(4), one Pb(1), and one Pb(3) atom to form distorted OK4Pb2 octahedra that share  a cornercorner with one O(8)K2Pb3 square pyramid,  a cornercorner with one O(5)K3Pb2 square pyramid, corners with two equivalent O(1)K3Pb2 square pyramids, corners with three equivalent O(6)K3Pb2 square pyramids,  an edgeedge with one O(2)K4Pb2 octahedra,  an edgeedge with one O(4)K4Pb2 octahedra,  an edgeedge with one O(3)K2Pb3 square pyramid,  an edgeedge with one O(7)K3Pb2 square pyramid, edges with two equivalent O(8)K2Pb3 square pyramids, edges with two equivalent O(1)K3Pb2 square pyramids, and edges with two equivalent O(5)K3Pb2 square pyramids. In the fifth O site, O(5) is bonded to one K(1), one K(3), one K(4), one Pb(1), and one Pb(4) atom to form distorted OK3Pb2 square pyramids that share  a cornercorner with one O(4)K4Pb2 octahedra, corners with three equivalent O(2)K4Pb2 octahedra, corners with two equivalent O(8)K2Pb3 square pyramids, corners with two equivalent O(1)K3Pb2 square pyramids, edges with two equivalent O(4)K4Pb2 octahedra,  an edgeedge with one O(3)K2Pb3 square pyramid,  an edgeedge with one O(8)K2Pb3 square pyramid,  an edgeedge with one O(1)K3Pb2 square pyramid,  an edgeedge with one O(6)K3Pb2 square pyramid, and  an edgeedge with one O(7)K3Pb2 square pyramid. The corner-sharing octahedral tilt angles range from 9-84°. In the sixth O site, O(6) is bonded to one K(1), one K(2), one K(3), one Pb(2), and one Pb(3) atom to form distorted OK3Pb2 square pyramids that share  a cornercorner with one O(2)K4Pb2 octahedra, corners with three equivalent O(4)K4Pb2 octahedra, corners with two equivalent O(3)K2Pb3 square pyramids, corners with two equivalent O(7)K3Pb2 square pyramids, edges with two equivalent O(2)K4Pb2 octahedra,  an edgeedge with one O(3)K2Pb3 square pyramid,  an edgeedge with one O(8)K2Pb3 square pyramid,  an edgeedge with one O(1)K3Pb2 square pyramid,  an edgeedge with one O(5)K3Pb2 square pyramid, and  an edgeedge with one O(7)K3Pb2 square pyramid. The corner-sharing octahedral tilt angles range from 9-84°. In the seventh O site, O(7) is bonded to one K(1), two equivalent K(2), one Pb(3), and one Pb(4) atom to form OK3Pb2 square pyramids that share corners with two equivalent O(2)K4Pb2 octahedra, corners with two equivalent O(3)K2Pb3 square pyramids, corners with two equivalent O(6)K3Pb2 square pyramids, corners with three equivalent O(8)K2Pb3 square pyramids,  an edgeedge with one O(4)K4Pb2 octahedra, edges with two equivalent O(2)K4Pb2 octahedra,  an edgeedge with one O(3)K2Pb3 square pyramid,  an edgeedge with one O(1)K3Pb2 square pyramid,  an edgeedge with one O(5)K3Pb2 square pyramid,  an edgeedge with one O(6)K3Pb2 square pyramid, and  an edgeedge with one O(7)K3Pb2 square pyramid. The corner-sharing octahedral tilt angles range from 14-18°. In the eighth O site, O(8) is bonded to one K(1), one K(4), one Pb(1), one Pb(3), and one Pb(4) atom to form OK2Pb3 square pyramids that share  a cornercorner with one O(4)K4Pb2 octahedra, corners with two equivalent O(1)K3Pb2 square pyramids, corners with two equivalent O(5)K3Pb2 square pyramids, corners with three equivalent O(7)K3Pb2 square pyramids,  an edgeedge with one O(2)K4Pb2 octahedra, edges with two equivalent O(4)K4Pb2 octahedra,  an edgeedge with one O(3)K2Pb3 square pyramid,  an edgeedge with one O(1)K3Pb2 square pyramid,  an edgeedge with one O(5)K3Pb2 square pyramid, and  an edgeedge with one O(6)K3Pb2 square pyramid. The corner-sharing octahedral tilt angles are 85°.
KPbO2 crystallizes in the triclinic P-1 space group. There are four inequivalent K sites. In the first K site, K(1) is bonded in a 6-coordinate geometry to one O(2), one O(4), one O(5), one O(6), one O(7), and one O(8) atom. The K(1)-O(2) bond length is 2.81 Å. The K(1)-O(4) bond length is 2.77 Å. The K(1)-O(5) bond length is 2.69 Å. The K(1)-O(6) bond length is 2.72 Å. The K(1)-O(7) bond length is 2.77 Å. The K(1)-O(8) bond length is 2.83 Å. In the second K site, K(2) is bonded to one O(3), one O(6), two equivalent O(2), and two equivalent O(7) atoms to form distorted KO6 octahedra that share corners with three equivalent Pb(4)O6 octahedra,  an edgeedge with one Pb(4)O6 octahedra, edges with two equivalent K(2)O6 octahedra, and edges with two equivalent Pb(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-17°. The K(2)-O(3) bond length is 2.84 Å. The K(2)-O(6) bond length is 2.74 Å. There is one shorter (2.74 Å) and one longer (3.05 Å) K(2)-O(2) bond length. There is one shorter (2.74 Å) and one longer (2.77 Å) K(2)-O(7) bond length. In the third K site, K(3) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom. The K(3)-O(1) bond length is 2.76 Å. The K(3)-O(2) bond length is 2.77 Å. The K(3)-O(3) bond length is 2.83 Å. The K(3)-O(4) bond length is 2.81 Å. The K(3)-O(5) bond length is 2.72 Å. The K(3)-O(6) bond length is 2.69 Å. In the fourth K site, K(4) is bonded to one O(5), one O(8), two equivalent O(1), and two equivalent O(4) atoms to form distorted KO6 octahedra that share corners with three equivalent Pb(3)O6 octahedra,  an edgeedge with one Pb(3)O6 octahedra, edges with two equivalent K(4)O6 octahedra, and edges with two equivalent Pb(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-16°. The K(4)-O(5) bond length is 2.74 Å. The K(4)-O(8) bond length is 2.85 Å. There is one shorter (2.74 Å) and one longer (2.76 Å) K(4)-O(1) bond length. There is one shorter (2.74 Å) and one longer (3.06 Å) K(4)-O(4) bond length. There are four inequivalent Pb sites. In the first Pb site, Pb(1) is bonded in a 3-coordinate geometry to one O(4), one O(5), and one O(8) atom. The Pb(1)-O(4) bond length is 2.24 Å. The Pb(1)-O(5) bond length is 2.22 Å. The Pb(1)-O(8) bond length is 2.24 Å. In the second Pb site, Pb(2) is bonded in a 3-coordinate geometry to one O(2), one O(3), and one O(6) atom. The Pb(2)-O(2) bond length is 2.24 Å. The Pb(2)-O(3) bond length is 2.24 Å. The Pb(2)-O(6) bond length is 2.23 Å. In the third Pb site, Pb(3) is bonded to one O(1), one O(3), one O(4), one O(6), one O(7), and one O(8) atom to form PbO6 octahedra that share corners with three equivalent K(4)O6 octahedra,  an edgeedge with one K(4)O6 octahedra, edges with two equivalent K(2)O6 octahedra, and edges with two equivalent Pb(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-16°. The Pb(3)-O(1) bond length is 2.23 Å. The Pb(3)-O(3) bond length is 2.37 Å. The Pb(3)-O(4) bond length is 2.17 Å. The Pb(3)-O(6) bond length is 2.14 Å. The Pb(3)-O(7) bond length is 2.22 Å. The Pb(3)-O(8) bond length is 2.37 Å. In the fourth Pb site, Pb(4) is bonded to one O(1), one O(2), one O(3), one O(5), one O(7), and one O(8) atom to form PbO6 octahedra that share corners with three equivalent K(2)O6 octahedra,  an edgeedge with one K(2)O6 octahedra, edges with two equivalent K(4)O6 octahedra, and edges with two equivalent Pb(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-17°. The Pb(4)-O(1) bond length is 2.22 Å. The Pb(4)-O(2) bond length is 2.17 Å. The Pb(4)-O(3) bond length is 2.37 Å. The Pb(4)-O(5) bond length is 2.14 Å. The Pb(4)-O(7) bond length is 2.23 Å. The Pb(4)-O(8) bond length is 2.37 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one K(3), two equivalent K(4), one Pb(3), and one Pb(4) atom to form OK3Pb2 square pyramids that share corners with two equivalent O(4)K4Pb2 octahedra, corners with two equivalent O(8)K2Pb3 square pyramids, corners with two equivalent O(5)K3Pb2 square pyramids, corners with three equivalent O(3)K2Pb3 square pyramids,  an edgeedge with one O(2)K4Pb2 octahedra, edges with two equivalent O(4)K4Pb2 octahedra,  an edgeedge with one O(8)K2Pb3 square pyramid,  an edgeedge with one O(1)K3Pb2 square pyramid,  an edgeedge with one O(5)K3Pb2 square pyramid,  an edgeedge with one O(6)K3Pb2 square pyramid, and  an edgeedge with one O(7)K3Pb2 square pyramid. The corner-sharing octahedral tilt angles range from 14-18°. In the second O site, O(2) is bonded to one K(1), one K(3), two equivalent K(2), one Pb(2), and one Pb(4) atom to form distorted OK4Pb2 octahedra that share  a cornercorner with one O(3)K2Pb3 square pyramid,  a cornercorner with one O(6)K3Pb2 square pyramid, corners with two equivalent O(7)K3Pb2 square pyramids, corners with three equivalent O(5)K3Pb2 square pyramids,  an edgeedge with one O(2)K4Pb2 octahedra,  an edgeedge with one O(4)K4Pb2 octahedra,  an edgeedge with one O(8)K2Pb3 square pyramid,  an edgeedge with one O(1)K3Pb2 square pyramid, edges with two equivalent O(3)K2Pb3 square pyramids, edges with two equivalent O(6)K3Pb2 square pyramids, and edges with two equivalent O(7)K3Pb2 square pyramids. In the third O site, O(3) is bonded to one K(2), one K(3), one Pb(2), one Pb(3), and one Pb(4) atom to form OK2Pb3 square pyramids that share  a cornercorner with one O(2)K4Pb2 octahedra, corners with two equivalent O(6)K3Pb2 square pyramids, corners with two equivalent O(7)K3Pb2 square pyramids, corners with three equivalent O(1)K3Pb2 square pyramids,  an edgeedge with one O(4)K4Pb2 octahedra, edges with two equivalent O(2)K4Pb2 octahedra,  an edgeedge with one O(8)K2Pb3 square pyramid,  an edgeedge with one O(5)K3Pb2 square pyramid,  an edgeedge with one O(6)K3Pb2 square pyramid, and  an edgeedge with one O(7)K3Pb2 square pyramid. The corner-sharing octahedral tilt angles are 85°. In the fourth O site, O(4) is bonded to one K(1), one K(3), two equivalent K(4), one Pb(1), and one Pb(3) atom to form distorted OK4Pb2 octahedra that share  a cornercorner with one O(8)K2Pb3 square pyramid,  a cornercorner with one O(5)K3Pb2 square pyramid, corners with two equivalent O(1)K3Pb2 square pyramids, corners with three equivalent O(6)K3Pb2 square pyramids,  an edgeedge with one O(2)K4Pb2 octahedra,  an edgeedge with one O(4)K4Pb2 octahedra,  an edgeedge with one O(3)K2Pb3 square pyramid,  an edgeedge with one O(7)K3Pb2 square pyramid, edges with two equivalent O(8)K2Pb3 square pyramids, edges with two equivalent O(1)K3Pb2 square pyramids, and edges with two equivalent O(5)K3Pb2 square pyramids. In the fifth O site, O(5) is bonded to one K(1), one K(3), one K(4), one Pb(1), and one Pb(4) atom to form distorted OK3Pb2 square pyramids that share  a cornercorner with one O(4)K4Pb2 octahedra, corners with three equivalent O(2)K4Pb2 octahedra, corners with two equivalent O(8)K2Pb3 square pyramids, corners with two equivalent O(1)K3Pb2 square pyramids, edges with two equivalent O(4)K4Pb2 octahedra,  an edgeedge with one O(3)K2Pb3 square pyramid,  an edgeedge with one O(8)K2Pb3 square pyramid,  an edgeedge with one O(1)K3Pb2 square pyramid,  an edgeedge with one O(6)K3Pb2 square pyramid, and  an edgeedge with one O(7)K3Pb2 square pyramid. The corner-sharing octahedral tilt angles range from 9-84°. In the sixth O site, O(6) is bonded to one K(1), one K(2), one K(3), one Pb(2), and one Pb(3) atom to form distorted OK3Pb2 square pyramids that share  a cornercorner with one O(2)K4Pb2 octahedra, corners with three equivalent O(4)K4Pb2 octahedra, corners with two equivalent O(3)K2Pb3 square pyramids, corners with two equivalent O(7)K3Pb2 square pyramids, edges with two equivalent O(2)K4Pb2 octahedra,  an edgeedge with one O(3)K2Pb3 square pyramid,  an edgeedge with one O(8)K2Pb3 square pyramid,  an edgeedge with one O(1)K3Pb2 square pyramid,  an edgeedge with one O(5)K3Pb2 square pyramid, and  an edgeedge with one O(7)K3Pb2 square pyramid. The corner-sharing octahedral tilt angles range from 9-84°. In the seventh O site, O(7) is bonded to one K(1), two equivalent K(2), one Pb(3), and one Pb(4) atom to form OK3Pb2 square pyramids that share corners with two equivalent O(2)K4Pb2 octahedra, corners with two equivalent O(3)K2Pb3 square pyramids, corners with two equivalent O(6)K3Pb2 square pyramids, corners with three equivalent O(8)K2Pb3 square pyramids,  an edgeedge with one O(4)K4Pb2 octahedra, edges with two equivalent O(2)K4Pb2 octahedra,  an edgeedge with one O(3)K2Pb3 square pyramid,  an edgeedge with one O(1)K3Pb2 square pyramid,  an edgeedge with one O(5)K3Pb2 square pyramid,  an edgeedge with one O(6)K3Pb2 square pyramid, and  an edgeedge with one O(7)K3Pb2 square pyramid. The corner-sharing octahedral tilt angles range from 14-18°. In the eighth O site, O(8) is bonded to one K(1), one K(4), one Pb(1), one Pb(3), and one Pb(4) atom to form OK2Pb3 square pyramids that share  a cornercorner with one O(4)K4Pb2 octahedra, corners with two equivalent O(1)K3Pb2 square pyramids, corners with two equivalent O(5)K3Pb2 square pyramids, corners with three equivalent O(7)K3Pb2 square pyramids,  an edgeedge with one O(2)K4Pb2 octahedra, edges with two equivalent O(4)K4Pb2 octahedra,  an edgeedge with one O(3)K2Pb3 square pyramid,  an edgeedge with one O(1)K3Pb2 square pyramid,  an edgeedge with one O(5)K3Pb2 square pyramid, and  an edgeedge with one O(6)K3Pb2 square pyramid. The corner-sharing octahedral tilt angles are 85°.