Materials Data on Na2Bi4O7 by Materials Project
Na2Bi4O7 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Na1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Na–O bond distances ranging from 2.31–2.61 Å. There are two inequivalent Bi3+ sites. In the first Bi3+ site, Bi3+ is bonded in a distorted rectangular see-saw-like geometry to four O2- atoms. There are a spread of Bi–O bond distances ranging from 2.13–2.32 Å. In the second Bi3+ site, Bi3+ is bonded in a distorted rectangular see-saw-like geometry to four O2- atoms. There are a spread of Bi–O bond distances ranging from 2.10–2.42 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Na1+ and two Bi3+ atoms to form a mixture of edge and corner-sharing ONa2Bi2 tetrahedra. In the second O2- site, O2- is bonded in a distorted T-shaped geometry to three Bi3+ atoms. In the third O2- site, O2- is bonded to two equivalent Na1+ and two equivalent Bi3+ atoms to form a mixture of distorted edge and corner-sharing ONa2Bi2 trigonal pyramids. In the fourth O2- site, O2- is bonded to two equivalent Na1+ and two equivalent Bi3+ atoms to form a mixture of distorted edge and corner-sharing ONa2Bi2 tetrahedra.