Materials Data on Bi4Te2Br2O9 by Materials Project

Abstract

Bi4Te2O9Br2 crystallizes in the orthorhombic Pmm2 space group. The structure is two-dimensional and consists of one Bi4Te2O9Br2 sheet oriented in the (0, 0, 1) direction. there are four inequivalent Bi3+ sites. In the first Bi3+ site, Bi3+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Bi–O bond distances ranging from 2.38–2.84 Å. In the second Bi3+ site, Bi3+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Bi–O bond distances ranging from 2.39–2.83 Å. In the third Bi3+ site, Bi3+ is bonded in a 4-coordinate geometry to four equivalent O2- and four Br1- atoms. All Bi–O bond lengths are 2.32 Å. There are two shorter (3.32 Å) and two longer (3.33 Å) Bi–Br bond lengths. In the fourth Bi3+ site, Bi3+ is bonded in a 4-coordinate geometry to four equivalent O2- and four Br1- atoms. All Bi–O bond lengths are 2.29 Å. There are two shorter (3.26 Å) and two longer (3.27 Å) Bi–Br bond lengths. There are two inequivalent Te4+ sites. In the first Te4+ site, Te4+ is bonded in a 4-coordinate geometry to four equivalent O2- atoms. All Te–O bond lengths are 2.02 Å. In the second Te4+ site, Te4+ is bonded in a distorted square pyramidal geometry to five O2- atoms. There are one shorter (1.88 Å) and four longer (2.16 Å) Te–O bond lengths. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to four Bi3+ atoms to form a mixture of edge and corner-sharing OBi4 tetrahedra. In the second O2- site, O2- is bonded in a 2-coordinate geometry to two Bi3+ and two Te4+ atoms. In the third O2- site, O2- is bonded in a single-bond geometry to four Bi3+ and one Te4+ atom. There are two inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a 4-coordinate geometry to four Bi3+ atoms. In the second Br1- site, Br1- is bonded in a 4-coordinate geometry to four Bi3+ atoms.