Materials Data on Na2Sm2B2O7 by Materials Project
Na2Sm2B2O7 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 2.39–2.92 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 2.37–2.67 Å. There are two inequivalent Sm3+ sites. In the first Sm3+ site, Sm3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Sm–O bond distances ranging from 2.31–2.54 Å. In the second Sm3+ site, Sm3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Sm–O bond distances ranging from 2.31–2.66 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 is two shorter (1.38 Å) and one longer (1.42 Å) B–O bond length. 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 1.37–1.41 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 Sm3+, and one B3+ atom. In the second O2- site, O2- is bonded to four Sm3+ atoms to form a mixture of edge and corner-sharing OSm4 tetrahedra. In the third O2- site, O2- is bonded in a distorted single-bond geometry to three Sm3+ and one B3+ atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to three Na1+, one Sm3+, and one B3+ atom. In the fifth O2- site, O2- is bonded in a distorted single-bond geometry to four Na1+, one Sm3+, and one B3+ atom. In the sixth O2- site, O2- is bonded in a distorted single-bond geometry to one Na1+, three Sm3+, and one B3+ atom. In the seventh O2- site, O2- is bonded in a distorted single-bond geometry to three Sm3+ and one B3+ atom.