NaB15 crystallizes in the orthorhombic Imma space group. Na(1) is bonded in a 16-coordinate geometry to two equivalent B(3), two equivalent B(4), four equivalent B(6), and eight equivalent B(5) atoms. There are six inequivalent B sites. In the first B site, B(1) is bonded in a distorted rectangular see-saw-like geometry to two equivalent B(2) and two equivalent B(4) atoms. In the second B site, B(2) is bonded in a 7-coordinate geometry to one B(1), one B(3), one B(4), two equivalent B(5), and two equivalent B(6) atoms. In the third B site, B(3) is bonded in a 7-coordinate geometry to one Na(1), one B(2), one B(3), two equivalent B(5), and two equivalent B(6) atoms. In the fourth B site, B(4) is bonded in a 6-coordinate geometry to one Na(1), one B(1), one B(2), one B(4), and two equivalent B(6) atoms. In the fifth B site, B(5) is bonded in a 8-coordinate geometry to two equivalent Na(1), one B(2), one B(3), two equivalent B(5), and two equivalent B(6) atoms. In the sixth B site, B(6) is bonded in a 7-coordinate geometry to one Na(1), one B(2), one B(3), one B(4), one B(6), and two equivalent B(5) atoms.
NaB15 crystallizes in the orthorhombic Imma space group. Na(1) is bonded in a 16-coordinate geometry to two equivalent B(3), two equivalent B(4), four equivalent B(6), and eight equivalent B(5) atoms. Both Na(1)-B(3) bond lengths are 2.60 Å. Both Na(1)-B(4) bond lengths are 2.48 Å. All Na(1)-B(6) bond lengths are 2.82 Å. There are four shorter (2.71 Å) and four longer (2.87 Å) Na(1)-B(5) bond lengths. There are six inequivalent B sites. In the first B site, B(1) is bonded in a distorted rectangular see-saw-like geometry to two equivalent B(2) and two equivalent B(4) atoms. Both B(1)-B(2) bond lengths are 1.75 Å. Both B(1)-B(4) bond lengths are 1.60 Å. In the second B site, B(2) is bonded in a 7-coordinate geometry to one B(1), one B(3), one B(4), two equivalent B(5), and two equivalent B(6) atoms. The B(2)-B(3) bond length is 1.80 Å. The B(2)-B(4) bond length is 2.11 Å. Both B(2)-B(5) bond lengths are 1.80 Å. Both B(2)-B(6) bond lengths are 1.76 Å. In the third B site, B(3) is bonded in a 7-coordinate geometry to one Na(1), one B(2), one B(3), two equivalent B(5), and two equivalent B(6) atoms. The B(3)-B(3) bond length is 1.75 Å. Both B(3)-B(5) bond lengths are 1.82 Å. Both B(3)-B(6) bond lengths are 1.82 Å. In the fourth B site, B(4) is bonded in a 6-coordinate geometry to one Na(1), one B(1), one B(2), one B(4), and two equivalent B(6) atoms. The B(4)-B(4) bond length is 2.15 Å. Both B(4)-B(6) bond lengths are 1.71 Å. In the fifth B site, B(5) is bonded in a 8-coordinate geometry to two equivalent Na(1), one B(2), one B(3), two equivalent B(5), and two equivalent B(6) atoms. There is one shorter (1.76 Å) and one longer (1.87 Å) B(5)-B(5) bond length. There is one shorter (1.79 Å) and one longer (1.81 Å) B(5)-B(6) bond length. In the sixth B site, B(6) is bonded in a 7-coordinate geometry to one Na(1), one B(2), one B(3), one B(4), one B(6), and two equivalent B(5) atoms. The B(6)-B(6) bond length is 1.78 Å.