Materials Data on Bi2Te5Pb2 by Materials Project
Pb2Bi2Te5 crystallizes in the trigonal P-3m1 space group. The structure is two-dimensional and consists of one Pb2Bi2Te5 sheet oriented in the (0, 0, 1) direction. Pb2+ is bonded to six Te2- atoms to form distorted PbTe6 octahedra that share corners with three equivalent BiTe6 octahedra, edges with three equivalent BiTe6 octahedra, and edges with six equivalent PbTe6 octahedra. The corner-sharing octahedral tilt angles are 12°. There are three shorter (3.06 Å) and three longer (3.66 Å) Pb–Te bond lengths. Bi3+ is bonded to six Te2- atoms to form BiTe6 octahedra that share corners with three equivalent PbTe6 octahedra, corners with three equivalent BiTe6 octahedra, edges with three equivalent PbTe6 octahedra, and edges with nine equivalent BiTe6 octahedra. The corner-sharing octahedra tilt angles range from 0–12°. There are three shorter (3.11 Å) and three longer (3.30 Å) Bi–Te bond lengths. There are three inequivalent Te2- sites. In the first Te2- site, Te2- is bonded in a 6-coordinate geometry to three equivalent Pb2+ atoms. In the second Te2- site, Te2- is bonded to three equivalent Pb2+ and three equivalent Bi3+ atoms to form TeBi3Pb3 octahedra that share corners with three equivalent TeBi6 octahedra and edges with nine TeBi3Pb3 octahedra. The corner-sharing octahedral tilt angles are 5°. In the third Te2- site, Te2- is bonded to six equivalent Bi3+ atoms to form a mixture of corner and edge-sharing TeBi6 octahedra. The corner-sharing octahedral tilt angles are 5°.