Materials Data on Na3Cr(BO3)2 by Materials Project
Na3Cr(BO3)2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are three inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Na–O bond distances ranging from 2.16–2.73 Å. In the second Na1+ site, Na1+ is bonded to five O2- atoms to form distorted NaO5 trigonal bipyramids that share a cornercorner with one CrO6 octahedra and edges with two equivalent CrO6 octahedra. The corner-sharing octahedral tilt angles are 18°. There are a spread of Na–O bond distances ranging from 2.33–2.36 Å. In the third Na1+ site, Na1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Na–O bond distances ranging from 2.28–2.42 Å. Cr3+ is bonded to six O2- atoms to form CrO6 octahedra that share a cornercorner with one NaO5 trigonal bipyramid and edges with two equivalent NaO5 trigonal bipyramids. There are a spread of Cr–O bond distances ranging from 2.01–2.18 Å. There are two inequivalent B3+ sites. In the first B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of B–O bond distances ranging from 1.37–1.41 Å. In the second B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There is two shorter (1.39 Å) and one longer (1.41 Å) B–O bond length. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to two Na1+, one Cr3+, and one B3+ atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one Cr3+, and one B3+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to four Na1+, one Cr3+, and one B3+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to three Na1+, one Cr3+, and one B3+ atom. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one Cr3+, and one B3+ atom. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one Cr3+, and one B3+ atom.