Na3BSiBiO7 crystallizes in the monoclinic P2_1/m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom. B(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. Si(1) is bonded to one O(5), one O(6), and two equivalent O(4) atoms to form SiO4 tetrahedra that share corners with four equivalent Bi(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-62°. Bi(1) is bonded to one O(2), one O(3), one O(5), one O(6), and two equivalent O(4) atoms to form BiO6 octahedra that share corners with four equivalent Si(1)O4 tetrahedra. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to two equivalent Na(1), two equivalent Na(2), and one B(1) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Na(1), two equivalent Na(2), one B(1), and one Bi(1) atom. In the third O site, O(3) is bonded to one Na(1), two equivalent Na(2), one B(1), and one Bi(1) atom to form distorted corner-sharing ONa3BiB trigonal bipyramids. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Si(1), and one Bi(1) atom. In the fifth O site, O(5) is bonded to two equivalent Na(2), one Si(1), and one Bi(1) atom to form distorted corner-sharing ONa2SiBi tetrahedra. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Na(2), one Si(1), and one Bi(1) atom.
Na3BSiBiO7 crystallizes in the monoclinic P2_1/m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms. The Na(1)-O(2) bond length is 2.43 Å. The Na(1)-O(3) bond length is 2.58 Å. There is one shorter (2.52 Å) and one longer (2.86 Å) Na(1)-O(1) bond length. Both Na(1)-O(4) bond lengths are 2.56 Å. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom. The Na(2)-O(1) bond length is 2.26 Å. The Na(2)-O(2) bond length is 2.60 Å. The Na(2)-O(3) bond length is 2.51 Å. The Na(2)-O(4) bond length is 2.56 Å. The Na(2)-O(5) bond length is 2.51 Å. The Na(2)-O(6) bond length is 2.46 Å. B(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. The B(1)-O(1) bond length is 1.34 Å. The B(1)-O(2) bond length is 1.41 Å. The B(1)-O(3) bond length is 1.43 Å. Si(1) is bonded to one O(5), one O(6), and two equivalent O(4) atoms to form SiO4 tetrahedra that share corners with four equivalent Bi(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-62°. The Si(1)-O(5) bond length is 1.65 Å. The Si(1)-O(6) bond length is 1.65 Å. Both Si(1)-O(4) bond lengths are 1.65 Å. Bi(1) is bonded to one O(2), one O(3), one O(5), one O(6), and two equivalent O(4) atoms to form BiO6 octahedra that share corners with four equivalent Si(1)O4 tetrahedra. The Bi(1)-O(2) bond length is 2.27 Å. The Bi(1)-O(3) bond length is 2.28 Å. The Bi(1)-O(5) bond length is 2.33 Å. The Bi(1)-O(6) bond length is 2.27 Å. Both Bi(1)-O(4) bond lengths are 2.26 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to two equivalent Na(1), two equivalent Na(2), and one B(1) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Na(1), two equivalent Na(2), one B(1), and one Bi(1) atom. In the third O site, O(3) is bonded to one Na(1), two equivalent Na(2), one B(1), and one Bi(1) atom to form distorted corner-sharing ONa3BiB trigonal bipyramids. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Si(1), and one Bi(1) atom. In the fifth O site, O(5) is bonded to two equivalent Na(2), one Si(1), and one Bi(1) atom to form distorted corner-sharing ONa2SiBi tetrahedra. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Na(2), one Si(1), and one Bi(1) atom.