Materials Data on Na2Er2B2O7 by Materials Project
Na2Er2B2O7 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.33–2.61 Å. In the second Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.34–2.82 Å. There are two inequivalent Er3+ sites. In the first Er3+ site, Er3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Er–O bond distances ranging from 2.25–2.51 Å. In the second Er3+ site, Er3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Er–O bond distances ranging from 2.24–2.62 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 1.36–1.40 Å. In the second 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 1.37–1.42 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to four Na1+, one Er3+, and one B3+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to three Er3+ and one B3+ atom. In the third O2- site, O2- is bonded to four Er3+ atoms to form a mixture of edge and corner-sharing OEr4 tetrahedra. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to one Na1+, three Er3+, and one B3+ atom. In the fifth O2- site, O2- is bonded in a distorted single-bond geometry to four Na1+, one Er3+, and one B3+ atom. In the sixth O2- site, O2- is bonded in a distorted single-bond geometry to three Na1+, one Er3+, and one B3+ atom. In the seventh O2- site, O2- is bonded in a 1-coordinate geometry to three Er3+ and one B3+ atom.