Materials Data on Ta2Bi2O9 by Materials Project
Bi2Ta2O9 crystallizes in the triclinic P-1 space group. The structure is two-dimensional and consists of one BiO2 sheet oriented in the (0, 0, 1) direction and one Ta2O5 sheet oriented in the (0, 0, 1) direction. In the BiO2 sheet, Bi4+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Bi–O bond distances ranging from 2.30–2.87 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to four equivalent Bi4+ atoms. In the second O2- site, O2- is bonded to four equivalent Bi4+ atoms to form a mixture of edge and corner-sharing OBi4 tetrahedra. In the Ta2O5 sheet, Ta5+ is bonded to five O2- atoms to form distorted corner-sharing TaO5 trigonal bipyramids. There is one shorter (1.90 Å) and four longer (1.94 Å) Ta–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear geometry to two equivalent Ta5+ atoms. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Ta5+ atoms.