DOE OSTI2020
(CuSe)4PbBi3O4 crystallizes in the tetragonal I4mm space group. The structure is two-dimensional and consists of two CuSe sheets oriented in the (0, 0, 1) direction and two PbBi3O4 sheets oriented in the (0, 0, 1) direction. In each CuSe sheet, Cu+1.25+ is bonded to four Se2- atoms to form a mixture of edge and corner-sharing CuSe4 tetrahedra. There are a spread of Cu–Se bond distances ranging from 2.49–2.52 Å. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 4-coordinate geometry to four equivalent Cu+1.25+ atoms. In the second Se2- site, Se2- is bonded in a 4-coordinate geometry to four equivalent Cu+1.25+ atoms. In the third Se2- site, Se2- is bonded in a 4-coordinate geometry to four equivalent Cu+1.25+ atoms. In each PbBi3O4 sheet, Pb2+ is bonded in a 4-coordinate geometry to four equivalent O2- atoms. All Pb–O bond lengths are 2.50 Å. There are two inequivalent Bi3+ sites. In the first Bi3+ site, Bi3+ is bonded in a 4-coordinate geometry to four equivalent O2- atoms. All Bi–O bond lengths are 2.28 Å. In the second Bi3+ site, Bi3+ is bonded in a 4-coordinate geometry to four equivalent O2- atoms. All Bi–O bond lengths are 2.31 Å. O2- is bonded to one Pb2+ and three Bi3+ atoms to form a mixture of edge and corner-sharing OBi3Pb tetrahedra.