Materials Data on Na2BiBAsO7 by Materials Project
Na2BBiAsO7 crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. Na is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Na–O bond distances ranging from 2.34–2.76 Å. B is bonded in a trigonal planar geometry to three O atoms. There are a spread of B–O bond distances ranging from 1.36–1.40 Å. Bi is bonded to six O atoms to form distorted BiO6 pentagonal pyramids that share corners with four equivalent AsO4 tetrahedra. There are a spread of Bi–O bond distances ranging from 2.24–2.67 Å. As is bonded to four O atoms to form AsO4 tetrahedra that share corners with four equivalent BiO6 pentagonal pyramids. There are a spread of As–O bond distances ranging from 1.71–1.76 Å. There are six inequivalent O sites. In the first O site, O is bonded in a distorted trigonal planar geometry to two equivalent Na and one B atom. In the second O site, O is bonded to two equivalent Na, one B, and one Bi atom to form distorted corner-sharing ONa2BiB trigonal pyramids. In the third O site, O is bonded in a 1-coordinate geometry to two equivalent Na, one B, and one Bi atom. In the fourth O site, O is bonded in a 3-coordinate geometry to one Na, one Bi, and one As atom. In the fifth O site, O is bonded in a distorted rectangular see-saw-like geometry to two equivalent Na, one Bi, and one As atom. In the sixth O site, O is bonded to two equivalent Na, one Bi, and one As atom to form distorted corner-sharing ONa2BiAs tetrahedra.