Materials Data on Bi2Pb2Se5 by Materials Project
Pb2Bi2Se5 is MAX Phase-like structured and crystallizes in the trigonal P-3m1 space group. The structure is two-dimensional and consists of one Pb2Bi2Se5 sheet oriented in the (0, 0, 1) direction. Pb2+ is bonded to six Se2- atoms to form PbSe6 octahedra that share corners with three equivalent PbSe6 octahedra, corners with three equivalent BiSe6 octahedra, edges with three equivalent BiSe6 octahedra, and edges with nine equivalent PbSe6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are three shorter (3.09 Å) and three longer (3.10 Å) Pb–Se bond lengths. Bi3+ is bonded to six Se2- atoms to form BiSe6 octahedra that share corners with three equivalent PbSe6 octahedra, edges with three equivalent PbSe6 octahedra, and edges with six equivalent BiSe6 octahedra. The corner-sharing octahedral tilt angles are 1°. There are three shorter (2.89 Å) and three longer (3.12 Å) Bi–Se bond lengths. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 3-coordinate geometry to three equivalent Bi3+ atoms. In the second Se2- site, Se2- is bonded to three equivalent Pb2+ and three equivalent Bi3+ atoms to form SeBi3Pb3 octahedra that share corners with three equivalent SePb6 octahedra and edges with nine SeBi3Pb3 octahedra. The corner-sharing octahedral tilt angles are 0°. In the third Se2- site, Se2- is bonded to six equivalent Pb2+ atoms to form a mixture of corner and edge-sharing SePb6 octahedra. The corner-sharing octahedral tilt angles are 0°.