K3B17 crystallizes in the tetragonal I4/mmm space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 24-coordinate geometry to four equivalent B(5), four equivalent B(8), eight equivalent B(2), and eight equivalent B(6) atoms. In the second K site, K(2) is bonded in a 22-coordinate geometry to two equivalent B(3), two equivalent B(4), two equivalent B(7), four equivalent B(2), four equivalent B(6), and eight equivalent B(1) atoms. There are eight inequivalent B sites. In the first B site, B(7) is bonded in a 8-coordinate geometry to four equivalent K(2) and four equivalent B(1) atoms. In the second B site, B(8) is bonded in a 5-coordinate geometry to four equivalent K(1), one B(8), and four equivalent B(6) atoms. In the third B site, B(1) is bonded in a 9-coordinate geometry to four equivalent K(2), one B(3), one B(7), and three equivalent B(1) atoms. In the fourth B site, B(2) is bonded in a 9-coordinate geometry to two equivalent K(1), two equivalent K(2), one B(4), one B(5), one B(6), and two equivalent B(2) atoms. In the fifth B site, B(3) is bonded in a 5-coordinate geometry to four equivalent K(2), one B(4), and four equivalent B(1) atoms. In the sixth B site, B(4) is bonded in a 9-coordinate geometry to four equivalent K(2), one B(3), and four equivalent B(2) atoms. In the seventh B site, B(5) is bonded in a 9-coordinate geometry to four equivalent K(1), one B(5), and four equivalent B(2) atoms. In the eighth B site, B(6) is bonded in a 8-coordinate geometry to two equivalent K(1), two equivalent K(2), one B(2), one B(8), and two equivalent B(6) atoms.
K3B17 crystallizes in the tetragonal I4/mmm space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 24-coordinate geometry to four equivalent B(5), four equivalent B(8), eight equivalent B(2), and eight equivalent B(6) atoms. All K(1)-B(5) bond lengths are 3.13 Å. All K(1)-B(8) bond lengths are 3.12 Å. All K(1)-B(2) bond lengths are 3.15 Å. All K(1)-B(6) bond lengths are 3.04 Å. In the second K site, K(2) is bonded in a 22-coordinate geometry to two equivalent B(3), two equivalent B(4), two equivalent B(7), four equivalent B(2), four equivalent B(6), and eight equivalent B(1) atoms. Both K(2)-B(3) bond lengths are 3.14 Å. Both K(2)-B(4) bond lengths are 3.11 Å. Both K(2)-B(7) bond lengths are 3.17 Å. All K(2)-B(2) bond lengths are 3.08 Å. All K(2)-B(6) bond lengths are 3.18 Å. There are four shorter (3.08 Å) and four longer (3.09 Å) K(2)-B(1) bond lengths. There are eight inequivalent B sites. In the first B site, B(7) is bonded in a 8-coordinate geometry to four equivalent K(2) and four equivalent B(1) atoms. All B(7)-B(1) bond lengths are 1.67 Å. In the second B site, B(8) is bonded in a 5-coordinate geometry to four equivalent K(1), one B(8), and four equivalent B(6) atoms. The B(8)-B(8) bond length is 1.73 Å. All B(8)-B(6) bond lengths are 1.72 Å. In the third B site, B(1) is bonded in a 9-coordinate geometry to four equivalent K(2), one B(3), one B(7), and three equivalent B(1) atoms. The B(1)-B(3) bond length is 1.74 Å. There is one shorter (1.66 Å) and two longer (1.83 Å) B(1)-B(1) bond lengths. In the fourth B site, B(2) is bonded in a 9-coordinate geometry to two equivalent K(1), two equivalent K(2), one B(4), one B(5), one B(6), and two equivalent B(2) atoms. The B(2)-B(4) bond length is 1.77 Å. The B(2)-B(5) bond length is 1.81 Å. The B(2)-B(6) bond length is 1.70 Å. Both B(2)-B(2) bond lengths are 1.79 Å. In the fifth B site, B(3) is bonded in a 5-coordinate geometry to four equivalent K(2), one B(4), and four equivalent B(1) atoms. The B(3)-B(4) bond length is 1.74 Å. In the sixth B site, B(4) is bonded in a 9-coordinate geometry to four equivalent K(2), one B(3), and four equivalent B(2) atoms. In the seventh B site, B(5) is bonded in a 9-coordinate geometry to four equivalent K(1), one B(5), and four equivalent B(2) atoms. The B(5)-B(5) bond length is 1.75 Å. In the eighth B site, B(6) is bonded in a 8-coordinate geometry to two equivalent K(1), two equivalent K(2), one B(2), one B(8), and two equivalent B(6) atoms. Both B(6)-B(6) bond lengths are 1.82 Å.