Na3CrBSiO7 crystallizes in the monoclinic Pm space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded in a 4-coordinate geometry to one O(1), one O(4), and two equivalent O(11) atoms. In the second Na site, Na(2) is bonded in a 4-coordinate geometry to one O(2), one O(3), and two equivalent O(12) atoms. In the third Na site, Na(3) is bonded in a 7-coordinate geometry to one O(1), one O(3), one O(5), one O(7), one O(9), and two equivalent O(11) atoms. In the fourth Na site, Na(4) is bonded in a 7-coordinate geometry to one O(10), one O(2), one O(4), one O(6), one O(8), and two equivalent O(12) atoms. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(10), one O(4), one O(6), one O(7), and two equivalent O(12) atoms to form CrO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra and corners with two equivalent Si(2)O4 tetrahedra. In the second Cr site, Cr(2) is bonded to one O(3), one O(5), one O(8), one O(9), and two equivalent O(11) atoms to form CrO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra and corners with two equivalent Si(2)O4 tetrahedra. There are two inequivalent B sites. In the first B site, B(1) is bonded in a trigonal planar geometry to one O(2), one O(3), and one O(5) atom. In the second B site, B(2) is bonded in a trigonal planar geometry to one O(1), one O(4), and one O(6) atom. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(10), one O(7), and two equivalent O(11) atoms to form SiO4 tetrahedra that share corners with two equivalent Cr(1)O6 octahedra and corners with two equivalent Cr(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 28-44°. In the second Si site, Si(2) is bonded to one O(8), one O(9), and two equivalent O(12) atoms to form SiO4 tetrahedra that share corners with two equivalent Cr(1)O6 octahedra and corners with two equivalent Cr(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 27-44°. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Na(1), two equivalent Na(3), and one B(2) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Na(2), two equivalent Na(4), and one B(1) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Na(2), two equivalent Na(3), one Cr(2), and one B(1) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to one Na(1), two equivalent Na(4), one Cr(1), and one B(2) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent Na(3), one Cr(2), and one B(1) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to two equivalent Na(4), one Cr(1), and one B(2) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to two equivalent Na(3), one Cr(1), and one Si(1) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to two equivalent Na(4), one Cr(2), and one Si(2) atom. In the ninth O site, O(9) is bonded in a rectangular see-saw-like geometry to two equivalent Na(3), one Cr(2), and one Si(2) atom. In the tenth O site, O(10) is bonded in a rectangular see-saw-like geometry to two equivalent Na(4), one Cr(1), and one Si(1) atom. In the eleventh O site, O(11) is bonded in a 5-coordinate geometry to one Na(1), two equivalent Na(3), one Cr(2), and one Si(1) atom. In the twelfth O site, O(12) is bonded in a 5-coordinate geometry to one Na(2), two equivalent Na(4), one Cr(1), and one Si(2) atom.
Na3CrBSiO7 crystallizes in the monoclinic Pm space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded in a 4-coordinate geometry to one O(1), one O(4), and two equivalent O(11) atoms. The Na(1)-O(1) bond length is 2.39 Å. The Na(1)-O(4) bond length is 2.35 Å. Both Na(1)-O(11) bond lengths are 2.52 Å. In the second Na site, Na(2) is bonded in a 4-coordinate geometry to one O(2), one O(3), and two equivalent O(12) atoms. The Na(2)-O(2) bond length is 2.39 Å. The Na(2)-O(3) bond length is 2.34 Å. Both Na(2)-O(12) bond lengths are 2.51 Å. In the third Na site, Na(3) is bonded in a 7-coordinate geometry to one O(1), one O(3), one O(5), one O(7), one O(9), and two equivalent O(11) atoms. The Na(3)-O(1) bond length is 2.27 Å. The Na(3)-O(3) bond length is 2.59 Å. The Na(3)-O(5) bond length is 2.34 Å. The Na(3)-O(7) bond length is 2.65 Å. The Na(3)-O(9) bond length is 2.35 Å. There is one shorter (2.57 Å) and one longer (2.89 Å) Na(3)-O(11) bond length. In the fourth Na site, Na(4) is bonded in a 7-coordinate geometry to one O(10), one O(2), one O(4), one O(6), one O(8), and two equivalent O(12) atoms. The Na(4)-O(10) bond length is 2.35 Å. The Na(4)-O(2) bond length is 2.27 Å. The Na(4)-O(4) bond length is 2.59 Å. The Na(4)-O(6) bond length is 2.33 Å. The Na(4)-O(8) bond length is 2.65 Å. There is one shorter (2.57 Å) and one longer (2.88 Å) Na(4)-O(12) bond length. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(10), one O(4), one O(6), one O(7), and two equivalent O(12) atoms to form CrO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra and corners with two equivalent Si(2)O4 tetrahedra. The Cr(1)-O(10) bond length is 1.92 Å. The Cr(1)-O(4) bond length is 2.00 Å. The Cr(1)-O(6) bond length is 1.95 Å. The Cr(1)-O(7) bond length is 1.99 Å. Both Cr(1)-O(12) bond lengths are 1.95 Å. In the second Cr site, Cr(2) is bonded to one O(3), one O(5), one O(8), one O(9), and two equivalent O(11) atoms to form CrO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra and corners with two equivalent Si(2)O4 tetrahedra. The Cr(2)-O(3) bond length is 2.01 Å. The Cr(2)-O(5) bond length is 1.94 Å. The Cr(2)-O(8) bond length is 1.99 Å. The Cr(2)-O(9) bond length is 1.92 Å. Both Cr(2)-O(11) bond lengths are 1.95 Å. There are two inequivalent B sites. In the first B site, B(1) is bonded in a trigonal planar geometry to one O(2), one O(3), and one O(5) atom. The B(1)-O(2) bond length is 1.34 Å. The B(1)-O(3) bond length is 1.40 Å. The B(1)-O(5) bond length is 1.42 Å. In the second B site, B(2) is bonded in a trigonal planar geometry to one O(1), one O(4), and one O(6) atom. The B(2)-O(1) bond length is 1.34 Å. The B(2)-O(4) bond length is 1.41 Å. The B(2)-O(6) bond length is 1.42 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(10), one O(7), and two equivalent O(11) atoms to form SiO4 tetrahedra that share corners with two equivalent Cr(1)O6 octahedra and corners with two equivalent Cr(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 28-44°. The Si(1)-O(10) bond length is 1.63 Å. The Si(1)-O(7) bond length is 1.64 Å. Both Si(1)-O(11) bond lengths are 1.65 Å. In the second Si site, Si(2) is bonded to one O(8), one O(9), and two equivalent O(12) atoms to form SiO4 tetrahedra that share corners with two equivalent Cr(1)O6 octahedra and corners with two equivalent Cr(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 27-44°. The Si(2)-O(8) bond length is 1.64 Å. The Si(2)-O(9) bond length is 1.64 Å. Both Si(2)-O(12) bond lengths are 1.65 Å. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Na(1), two equivalent Na(3), and one B(2) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Na(2), two equivalent Na(4), and one B(1) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Na(2), two equivalent Na(3), one Cr(2), and one B(1) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to one Na(1), two equivalent Na(4), one Cr(1), and one B(2) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent Na(3), one Cr(2), and one B(1) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to two equivalent Na(4), one Cr(1), and one B(2) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to two equivalent Na(3), one Cr(1), and one Si(1) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to two equivalent Na(4), one Cr(2), and one Si(2) atom. In the ninth O site, O(9) is bonded in a rectangular see-saw-like geometry to two equivalent Na(3), one Cr(2), and one Si(2) atom. In the tenth O site, O(10) is bonded in a rectangular see-saw-like geometry to two equivalent Na(4), one Cr(1), and one Si(1) atom. In the eleventh O site, O(11) is bonded in a 5-coordinate geometry to one Na(1), two equivalent Na(3), one Cr(2), and one Si(1) atom. In the twelfth O site, O(12) is bonded in a 5-coordinate geometry to one Na(2), two equivalent Na(4), one Cr(1), and one Si(2) atom.