Materials Data on Ca2Bi2O5 by Materials Project
Ca2Bi2O5 crystallizes in the orthorhombic Pbam space group. The structure is three-dimensional. Ca2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ca–O bond distances ranging from 2.36–2.83 Å. Bi3+ is bonded to five O2- atoms to form distorted corner-sharing BiO5 square pyramids. There are a spread of Bi–O bond distances ranging from 2.14–2.64 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to four equivalent Ca2+ and two equivalent Bi3+ atoms to form distorted OCa4Bi2 octahedra that share corners with four equivalent OCa3Bi2 trigonal bipyramids, edges with two equivalent OCa4Bi2 octahedra, and faces with four equivalent OCa3Bi2 trigonal bipyramids. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ca2+ and two equivalent Bi3+ atoms. In the third O2- site, O2- is bonded to three equivalent Ca2+ and two equivalent Bi3+ atoms to form distorted OCa3Bi2 trigonal bipyramids that share corners with two equivalent OCa4Bi2 octahedra, corners with six equivalent OCa3Bi2 trigonal bipyramids, an edgeedge with one OCa3Bi2 trigonal bipyramid, and faces with two equivalent OCa4Bi2 octahedra. The corner-sharing octahedral tilt angles are 55°.