Materials Data on Na2Cu2(B4O7)3 by Materials Project
Na2Cu2B12O21 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Na1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Na–O bond distances ranging from 2.37–2.82 Å. Cu2+ is bonded to six O2- atoms to form distorted CuO6 octahedra that share corners with four BO4 tetrahedra and an edgeedge with one CuO6 octahedra. There are a spread of Cu–O bond distances ranging from 1.97–2.70 Å. There are six inequivalent B3+ sites. In the first B3+ site, B3+ is bonded to four O2- atoms to form BO4 tetrahedra that share corners with two equivalent CuO6 octahedra and a cornercorner with one BO4 tetrahedra. The corner-sharing octahedra tilt angles range from 57–61°. There are a spread of B–O bond distances ranging from 1.42–1.60 Å. In the second B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There is one shorter (1.36 Å) and two longer (1.39 Å) B–O bond length. In the third B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There is one shorter (1.37 Å) and two longer (1.38 Å) B–O bond length. In the fourth B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There is one shorter (1.37 Å) and two longer (1.38 Å) B–O bond length. In the fifth B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There is two shorter (1.36 Å) and one longer (1.41 Å) B–O bond length. In the sixth B3+ site, B3+ is bonded to four O2- atoms to form BO4 tetrahedra that share corners with two equivalent CuO6 octahedra. The corner-sharing octahedra tilt angles range from 63–64°. There are a spread of B–O bond distances ranging from 1.44–1.56 Å. There are eleven inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Na1+, one Cu2+, and two B3+ atoms. In the second O2- site, O2- is bonded in a trigonal planar geometry to one Cu2+ and two B3+ atoms. In the third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Na1+, one Cu2+, and two B3+ atoms. In the fourth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Na1+ and two B3+ atoms. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to one Na1+, two equivalent Cu2+, and one B3+ atom. In the sixth O2- site, O2- is bonded in a bent 120 degrees geometry to two equivalent B3+ atoms. In the seventh O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Na1+ and two B3+ atoms. In the eighth O2- site, O2- is bonded in a bent 120 degrees geometry to two B3+ atoms. In the ninth O2- site, O2- is bonded in a bent 120 degrees geometry to one Na1+ and two B3+ atoms. In the tenth O2- site, O2- is bonded in a trigonal planar geometry to one Cu2+ and two B3+ atoms. In the eleventh O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Na1+ and two B3+ atoms.