B8P crystallizes in the monoclinic Cm space group. There are sixteen inequivalent B sites. In the first B site, B(1) is bonded in a 6-coordinate geometry to one B(11), one B(14), one B(6), one B(7), one B(9), and one P(2) atom. In the second B site, B(2) is bonded in a 6-coordinate geometry to one B(10), one B(12), one B(13), one B(5), one B(8), and one P(3) atom. In the third B site, B(3) is bonded in a 6-coordinate geometry to one B(15), two equivalent B(10), two equivalent B(5), and one P(2) atom. In the fourth B site, B(4) is bonded in a 6-coordinate geometry to one B(16), two equivalent B(6), two equivalent B(9), and one P(3) atom. In the fifth B site, B(5) is bonded in a 5-coordinate geometry to one B(10), one B(13), one B(15), one B(2), and one B(3) atom. In the sixth B site, B(6) is bonded in a 6-coordinate geometry to one B(1), one B(14), one B(16), one B(4), one B(9), and one P(1) atom. In the seventh B site, B(7) is bonded in a 5-coordinate geometry to one B(11), two equivalent B(1), and two equivalent B(14) atoms. In the eighth B site, B(8) is bonded in a 6-coordinate geometry to one B(12), two equivalent B(13), two equivalent B(2), and one P(1) atom. In the ninth B site, B(9) is bonded in a 6-coordinate geometry to one B(1), one B(11), one B(14), one B(4), one B(6), and one B(9) atom. In the tenth B site, B(10) is bonded in a 6-coordinate geometry to one B(10), one B(12), one B(13), one B(2), one B(3), and one B(5) atom. In the eleventh B site, B(11) is bonded in a 6-coordinate geometry to one B(15), one B(7), two equivalent B(1), and two equivalent B(9) atoms. In the twelfth B site, B(12) is bonded in a 6-coordinate geometry to one B(16), one B(8), two equivalent B(10), and two equivalent B(2) atoms. In the thirteenth B site, B(13) is bonded in a 6-coordinate geometry to one B(10), one B(13), one B(15), one B(2), one B(5), and one B(8) atom. In the fourteenth B site, B(14) is bonded in a 6-coordinate geometry to one B(1), one B(14), one B(16), one B(6), one B(7), and one B(9) atom. In the fifteenth B site, B(15) is bonded in a 6-coordinate geometry to one B(11), one B(3), two equivalent B(13), and two equivalent B(5) atoms. In the sixteenth B site, B(16) is bonded in a 6-coordinate geometry to one B(12), one B(4), two equivalent B(14), and two equivalent B(6) atoms. There are three inequivalent P sites. In the first P site, P(1) is bonded in a distorted tetrahedral geometry to one B(8), two equivalent B(6), and one P(3) atom. In the second P site, P(2) is bonded in a trigonal non-coplanar geometry to one B(3) and two equivalent B(1) atoms. In the third P site, P(3) is bonded in a distorted tetrahedral geometry to one B(4), two equivalent B(2), and one P(1) atom.
B8P crystallizes in the monoclinic Cm space group. There are sixteen inequivalent B sites. In the first B site, B(1) is bonded in a 6-coordinate geometry to one B(11), one B(14), one B(6), one B(7), one B(9), and one P(2) atom. The B(1)-B(11) bond length is 1.77 Å. The B(1)-B(14) bond length is 1.81 Å. The B(1)-B(6) bond length is 1.74 Å. The B(1)-B(7) bond length is 1.73 Å. The B(1)-B(9) bond length is 1.77 Å. The B(1)-P(2) bond length is 1.87 Å. In the second B site, B(2) is bonded in a 6-coordinate geometry to one B(10), one B(12), one B(13), one B(5), one B(8), and one P(3) atom. The B(2)-B(10) bond length is 1.77 Å. The B(2)-B(12) bond length is 1.78 Å. The B(2)-B(13) bond length is 1.81 Å. The B(2)-B(5) bond length is 1.73 Å. The B(2)-B(8) bond length is 1.75 Å. The B(2)-P(3) bond length is 1.90 Å. In the third B site, B(3) is bonded in a 6-coordinate geometry to one B(15), two equivalent B(10), two equivalent B(5), and one P(2) atom. The B(3)-B(15) bond length is 1.81 Å. Both B(3)-B(10) bond lengths are 1.77 Å. Both B(3)-B(5) bond lengths are 1.73 Å. The B(3)-P(2) bond length is 1.85 Å. In the fourth B site, B(4) is bonded in a 6-coordinate geometry to one B(16), two equivalent B(6), two equivalent B(9), and one P(3) atom. The B(4)-B(16) bond length is 1.81 Å. Both B(4)-B(6) bond lengths are 1.74 Å. Both B(4)-B(9) bond lengths are 1.77 Å. The B(4)-P(3) bond length is 1.90 Å. In the fifth B site, B(5) is bonded in a 5-coordinate geometry to one B(10), one B(13), one B(15), one B(2), and one B(3) atom. The B(5)-B(10) bond length is 1.78 Å. The B(5)-B(13) bond length is 1.76 Å. The B(5)-B(15) bond length is 1.79 Å. In the sixth B site, B(6) is bonded in a 6-coordinate geometry to one B(1), one B(14), one B(16), one B(4), one B(9), and one P(1) atom. The B(6)-B(14) bond length is 1.79 Å. The B(6)-B(16) bond length is 1.77 Å. The B(6)-B(9) bond length is 1.81 Å. The B(6)-P(1) bond length is 1.90 Å. In the seventh B site, B(7) is bonded in a 5-coordinate geometry to one B(11), two equivalent B(1), and two equivalent B(14) atoms. The B(7)-B(11) bond length is 1.78 Å. Both B(7)-B(14) bond lengths are 1.78 Å. In the eighth B site, B(8) is bonded in a 6-coordinate geometry to one B(12), two equivalent B(13), two equivalent B(2), and one P(1) atom. The B(8)-B(12) bond length is 1.82 Å. Both B(8)-B(13) bond lengths are 1.79 Å. The B(8)-P(1) bond length is 1.92 Å. In the ninth B site, B(9) is bonded in a 6-coordinate geometry to one B(1), one B(11), one B(14), one B(4), one B(6), and one B(9) atom. The B(9)-B(11) bond length is 1.84 Å. The B(9)-B(14) bond length is 1.73 Å. The B(9)-B(9) bond length is 1.86 Å. In the tenth B site, B(10) is bonded in a 6-coordinate geometry to one B(10), one B(12), one B(13), one B(2), one B(3), and one B(5) atom. The B(10)-B(10) bond length is 1.87 Å. The B(10)-B(12) bond length is 1.89 Å. The B(10)-B(13) bond length is 1.74 Å. In the eleventh B site, B(11) is bonded in a 6-coordinate geometry to one B(15), one B(7), two equivalent B(1), and two equivalent B(9) atoms. The B(11)-B(15) bond length is 1.71 Å. In the twelfth B site, B(12) is bonded in a 6-coordinate geometry to one B(16), one B(8), two equivalent B(10), and two equivalent B(2) atoms. The B(12)-B(16) bond length is 1.75 Å. In the thirteenth B site, B(13) is bonded in a 6-coordinate geometry to one B(10), one B(13), one B(15), one B(2), one B(5), and one B(8) atom. The B(13)-B(13) bond length is 1.91 Å. The B(13)-B(15) bond length is 1.86 Å. In the fourteenth B site, B(14) is bonded in a 6-coordinate geometry to one B(1), one B(14), one B(16), one B(6), one B(7), and one B(9) atom. The B(14)-B(14) bond length is 1.86 Å. The B(14)-B(16) bond length is 1.89 Å. In the fifteenth B site, B(15) is bonded in a 6-coordinate geometry to one B(11), one B(3), two equivalent B(13), and two equivalent B(5) atoms. In the sixteenth B site, B(16) is bonded in a 6-coordinate geometry to one B(12), one B(4), two equivalent B(14), and two equivalent B(6) atoms. There are three inequivalent P sites. In the first P site, P(1) is bonded in a distorted tetrahedral geometry to one B(8), two equivalent B(6), and one P(3) atom. The P(1)-P(3) bond length is 2.25 Å. In the second P site, P(2) is bonded in a trigonal non-coplanar geometry to one B(3) and two equivalent B(1) atoms. In the third P site, P(3) is bonded in a distorted tetrahedral geometry to one B(4), two equivalent B(2), and one P(1) atom.