Na3Mn2BO6 crystallizes in the triclinic P-1 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form NaO6 octahedra that share corners with four equivalent Mn(1)O5 square pyramids, edges with two equivalent Na(1)O6 octahedra, edges with four equivalent Na(2)O6 octahedra, and edges with six equivalent Mn(1)O5 square pyramids. In the second Na site, Na(2) is bonded to one O(2), two equivalent O(1), and three equivalent O(3) atoms to form distorted NaO6 octahedra that share corners with five equivalent Mn(1)O5 square pyramids, edges with two equivalent Na(1)O6 octahedra, edges with four equivalent Na(2)O6 octahedra, and  an edgeedge with one Mn(1)O5 square pyramid. Mn(1) is bonded to two equivalent O(1) and three equivalent O(2) atoms to form distorted MnO5 square pyramids that share corners with two equivalent Na(1)O6 octahedra, corners with five equivalent Na(2)O6 octahedra,  an edgeedge with one Na(2)O6 octahedra, edges with three equivalent Na(1)O6 octahedra, and edges with four equivalent Mn(1)O5 square pyramids. The corner-sharing octahedral tilt angles range from 11-82°. B(1) is bonded in a linear geometry to two equivalent O(3) atoms. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), two equivalent Na(2), and two equivalent Mn(1) atoms to form ONa3Mn2 square pyramids that share corners with two equivalent O(2)Na3Mn3 octahedra,  a cornercorner with one O(1)Na3Mn2 square pyramid, edges with five equivalent O(2)Na3Mn3 octahedra, and edges with two equivalent O(1)Na3Mn2 square pyramids. The corner-sharing octahedral tilt angles are 3°. In the second O site, O(2) is bonded to one Na(2), two equivalent Na(1), and three equivalent Mn(1) atoms to form distorted ONa3Mn3 octahedra that share corners with two equivalent O(2)Na3Mn3 octahedra, corners with two equivalent O(1)Na3Mn2 square pyramids, edges with five equivalent O(2)Na3Mn3 octahedra, and edges with five equivalent O(1)Na3Mn2 square pyramids. The corner-sharing octahedra are not tilted. In the third O site, O(3) is bonded in a 1-coordinate geometry to three equivalent Na(2) and one B(1) atom.
Na3Mn2BO6 crystallizes in the triclinic P-1 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form NaO6 octahedra that share corners with four equivalent Mn(1)O5 square pyramids, edges with two equivalent Na(1)O6 octahedra, edges with four equivalent Na(2)O6 octahedra, and edges with six equivalent Mn(1)O5 square pyramids. Both Na(1)-O(1) bond lengths are 2.36 Å. There are two shorter (2.40 Å) and two longer (2.41 Å) Na(1)-O(2) bond lengths. In the second Na site, Na(2) is bonded to one O(2), two equivalent O(1), and three equivalent O(3) atoms to form distorted NaO6 octahedra that share corners with five equivalent Mn(1)O5 square pyramids, edges with two equivalent Na(1)O6 octahedra, edges with four equivalent Na(2)O6 octahedra, and  an edgeedge with one Mn(1)O5 square pyramid. The Na(2)-O(2) bond length is 2.59 Å. There is one shorter (2.35 Å) and one longer (2.36 Å) Na(2)-O(1) bond length. There are a spread of Na(2)-O(3) bond distances ranging from 2.31-2.81 Å. Mn(1) is bonded to two equivalent O(1) and three equivalent O(2) atoms to form distorted MnO5 square pyramids that share corners with two equivalent Na(1)O6 octahedra, corners with five equivalent Na(2)O6 octahedra,  an edgeedge with one Na(2)O6 octahedra, edges with three equivalent Na(1)O6 octahedra, and edges with four equivalent Mn(1)O5 square pyramids. The corner-sharing octahedral tilt angles range from 11-82°. Both Mn(1)-O(1) bond lengths are 1.95 Å. There are two shorter (1.97 Å) and one longer (2.38 Å) Mn(1)-O(2) bond length. B(1) is bonded in a linear geometry to two equivalent O(3) atoms. Both B(1)-O(3) bond lengths are 1.27 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), two equivalent Na(2), and two equivalent Mn(1) atoms to form ONa3Mn2 square pyramids that share corners with two equivalent O(2)Na3Mn3 octahedra,  a cornercorner with one O(1)Na3Mn2 square pyramid, edges with five equivalent O(2)Na3Mn3 octahedra, and edges with two equivalent O(1)Na3Mn2 square pyramids. The corner-sharing octahedral tilt angles are 3°. In the second O site, O(2) is bonded to one Na(2), two equivalent Na(1), and three equivalent Mn(1) atoms to form distorted ONa3Mn3 octahedra that share corners with two equivalent O(2)Na3Mn3 octahedra, corners with two equivalent O(1)Na3Mn2 square pyramids, edges with five equivalent O(2)Na3Mn3 octahedra, and edges with five equivalent O(1)Na3Mn2 square pyramids. The corner-sharing octahedra are not tilted. In the third O site, O(3) is bonded in a 1-coordinate geometry to three equivalent Na(2) and one B(1) atom.