KBa2As5 is Magnesium tetraboride-derived structured and crystallizes in the monoclinic Cm space group. There are four inequivalent K sites. In the first K site, K(1) is bonded in a 8-coordinate geometry to one As(13), one As(2), two equivalent As(1), two equivalent As(15), and two equivalent As(4) atoms. In the second K site, K(2) is bonded in a 8-coordinate geometry to one As(10), one As(11), one As(15), one As(4), one As(6), one As(9), and two equivalent As(7) atoms. In the third K site, K(3) is bonded in a 8-coordinate geometry to one As(10), one As(11), one As(12), one As(16), one As(3), one As(5), and two equivalent As(8) atoms. In the fourth K site, K(4) is bonded in a 7-coordinate geometry to one As(2), two equivalent As(14), two equivalent As(15), two equivalent As(4), and two equivalent As(6) atoms. There are eight inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 9-coordinate geometry to one As(13), two equivalent As(1), two equivalent As(16), two equivalent As(3), and two equivalent As(5) atoms. In the second Ba site, Ba(2) is bonded in a 8-coordinate geometry to one As(1), one As(4), one As(5), one As(6), one As(7), one As(8), and two equivalent As(9) atoms. In the third Ba site, Ba(3) is bonded in a 8-coordinate geometry to one As(14), one As(3), one As(4), one As(5), one As(7), one As(8), and two equivalent As(12) atoms. In the fourth Ba site, Ba(4) is bonded in a 9-coordinate geometry to one As(10), one As(12), one As(14), one As(16), one As(5), one As(6), one As(9), and two equivalent As(8) atoms. In the fifth Ba site, Ba(5) is bonded in a 9-coordinate geometry to one As(1), one As(11), one As(12), one As(15), one As(3), one As(4), one As(9), and two equivalent As(7) atoms. In the sixth Ba site, Ba(6) is bonded in a 8-coordinate geometry to one As(13), one As(2), two equivalent As(14), two equivalent As(16), and two equivalent As(5) atoms. In the seventh Ba site, Ba(7) is bonded in a 8-coordinate geometry to two equivalent As(1), two equivalent As(15), two equivalent As(16), and two equivalent As(6) atoms. In the eighth Ba site, Ba(8) is bonded in a 8-coordinate geometry to two equivalent As(14), two equivalent As(15), two equivalent As(16), and two equivalent As(3) atoms. There are sixteen inequivalent As sites. In the first As site, As(1) is bonded to one K(1), one Ba(1), one Ba(2), one Ba(5), one Ba(7), one As(10), and one As(15) atom to form a mixture of distorted face and corner-sharing AsKBa4As2 pentagonal bipyramids. In the second As site, As(2) is bonded in a 5-coordinate geometry to one K(1), one K(4), one Ba(6), and two equivalent As(3) atoms. In the third As site, As(3) is bonded in a 7-coordinate geometry to one K(3), one Ba(1), one Ba(3), one Ba(5), one Ba(8), one As(2), and one As(5) atom. In the fourth As site, As(4) is bonded in a 8-coordinate geometry to one K(1), one K(2), one K(4), one Ba(2), one Ba(3), one Ba(5), one As(6), and one As(7) atom. In the fifth As site, As(5) is bonded in a 8-coordinate geometry to one K(3), one Ba(1), one Ba(2), one Ba(3), one Ba(4), one Ba(6), one As(3), and one As(8) atom. In the sixth As site, As(6) is bonded in a 7-coordinate geometry to one K(2), one K(4), one Ba(2), one Ba(4), one Ba(7), one As(13), and one As(4) atom. In the seventh As site, As(7) is bonded in a 8-coordinate geometry to two equivalent K(2), one Ba(2), one Ba(3), two equivalent Ba(5), one As(4), and one As(9) atom. In the eighth As site, As(8) is bonded in a 8-coordinate geometry to two equivalent K(3), one Ba(2), one Ba(3), two equivalent Ba(4), one As(12), and one As(5) atom. In the ninth As site, As(9) is bonded to one K(2), one Ba(4), one Ba(5), two equivalent Ba(2), one As(10), and one As(7) atom to form a mixture of distorted face and corner-sharing AsKBa4As2 pentagonal bipyramids. In the tenth As site, As(10) is bonded in a 5-coordinate geometry to one K(2), one K(3), one Ba(4), one As(1), and one As(9) atom. In the eleventh As site, As(11) is bonded in a 5-coordinate geometry to one K(2), one K(3), one Ba(5), one As(12), and one As(14) atom. In the twelfth As site, As(12) is bonded to one K(3), one Ba(4), one Ba(5), two equivalent Ba(3), one As(11), and one As(8) atom to form distorted corner-sharing AsKBa4As2 pentagonal bipyramids. In the thirteenth As site, As(13) is bonded in a 5-coordinate geometry to one K(1), one Ba(1), one Ba(6), and two equivalent As(6) atoms. In the fourteenth As site, As(14) is bonded in a 7-coordinate geometry to one K(4), one Ba(3), one Ba(4), one Ba(6), one Ba(8), one As(11), and one As(16) atom. In the fifteenth As site, As(15) is bonded in a 8-coordinate geometry to one K(1), one K(2), one K(4), one Ba(5), one Ba(7), one Ba(8), one As(1), and one As(15) atom. In the sixteenth As site, As(16) is bonded in a 8-coordinate geometry to one K(3), one Ba(1), one Ba(4), one Ba(6), one Ba(7), one Ba(8), one As(14), and one As(16) atom.
KBa2As5 is Magnesium tetraboride-derived structured and crystallizes in the monoclinic Cm space group. There are four inequivalent K sites. In the first K site, K(1) is bonded in a 8-coordinate geometry to one As(13), one As(2), two equivalent As(1), two equivalent As(15), and two equivalent As(4) atoms. The K(1)-As(13) bond length is 3.40 Å. The K(1)-As(2) bond length is 3.42 Å. Both K(1)-As(1) bond lengths are 3.31 Å. Both K(1)-As(15) bond lengths are 3.56 Å. Both K(1)-As(4) bond lengths are 3.39 Å. In the second K site, K(2) is bonded in a 8-coordinate geometry to one As(10), one As(11), one As(15), one As(4), one As(6), one As(9), and two equivalent As(7) atoms. The K(2)-As(10) bond length is 3.45 Å. The K(2)-As(11) bond length is 3.44 Å. The K(2)-As(15) bond length is 3.42 Å. The K(2)-As(4) bond length is 3.49 Å. The K(2)-As(6) bond length is 3.29 Å. The K(2)-As(9) bond length is 3.35 Å. There is one shorter (3.46 Å) and one longer (3.59 Å) K(2)-As(7) bond length. In the third K site, K(3) is bonded in a 8-coordinate geometry to one As(10), one As(11), one As(12), one As(16), one As(3), one As(5), and two equivalent As(8) atoms. The K(3)-As(10) bond length is 3.41 Å. The K(3)-As(11) bond length is 3.42 Å. The K(3)-As(12) bond length is 3.28 Å. The K(3)-As(16) bond length is 3.44 Å. The K(3)-As(3) bond length is 3.27 Å. The K(3)-As(5) bond length is 3.59 Å. There is one shorter (3.42 Å) and one longer (3.59 Å) K(3)-As(8) bond length. In the fourth K site, K(4) is bonded in a 7-coordinate geometry to one As(2), two equivalent As(14), two equivalent As(15), two equivalent As(4), and two equivalent As(6) atoms. The K(4)-As(2) bond length is 3.47 Å. Both K(4)-As(14) bond lengths are 3.79 Å. Both K(4)-As(15) bond lengths are 3.65 Å. Both K(4)-As(4) bond lengths are 3.57 Å. Both K(4)-As(6) bond lengths are 3.84 Å. There are eight inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 9-coordinate geometry to one As(13), two equivalent As(1), two equivalent As(16), two equivalent As(3), and two equivalent As(5) atoms. The Ba(1)-As(13) bond length is 3.47 Å. Both Ba(1)-As(1) bond lengths are 3.59 Å. Both Ba(1)-As(16) bond lengths are 3.58 Å. Both Ba(1)-As(3) bond lengths are 3.73 Å. Both Ba(1)-As(5) bond lengths are 3.55 Å. In the second Ba site, Ba(2) is bonded in a 8-coordinate geometry to one As(1), one As(4), one As(5), one As(6), one As(7), one As(8), and two equivalent As(9) atoms. The Ba(2)-As(1) bond length is 3.35 Å. The Ba(2)-As(4) bond length is 3.38 Å. The Ba(2)-As(5) bond length is 3.38 Å. The Ba(2)-As(6) bond length is 3.37 Å. The Ba(2)-As(7) bond length is 3.39 Å. The Ba(2)-As(8) bond length is 3.38 Å. There is one shorter (3.33 Å) and one longer (3.42 Å) Ba(2)-As(9) bond length. In the third Ba site, Ba(3) is bonded in a 8-coordinate geometry to one As(14), one As(3), one As(4), one As(5), one As(7), one As(8), and two equivalent As(12) atoms. The Ba(3)-As(14) bond length is 3.38 Å. The Ba(3)-As(3) bond length is 3.43 Å. The Ba(3)-As(4) bond length is 3.40 Å. The Ba(3)-As(5) bond length is 3.46 Å. The Ba(3)-As(7) bond length is 3.40 Å. The Ba(3)-As(8) bond length is 3.40 Å. There is one shorter (3.41 Å) and one longer (3.42 Å) Ba(3)-As(12) bond length. In the fourth Ba site, Ba(4) is bonded in a 9-coordinate geometry to one As(10), one As(12), one As(14), one As(16), one As(5), one As(6), one As(9), and two equivalent As(8) atoms. The Ba(4)-As(10) bond length is 3.48 Å. The Ba(4)-As(12) bond length is 3.69 Å. The Ba(4)-As(14) bond length is 3.68 Å. The Ba(4)-As(16) bond length is 3.52 Å. The Ba(4)-As(5) bond length is 3.62 Å. The Ba(4)-As(6) bond length is 3.60 Å. The Ba(4)-As(9) bond length is 3.66 Å. There is one shorter (3.52 Å) and one longer (3.55 Å) Ba(4)-As(8) bond length. In the fifth Ba site, Ba(5) is bonded in a 9-coordinate geometry to one As(1), one As(11), one As(12), one As(15), one As(3), one As(4), one As(9), and two equivalent As(7) atoms. The Ba(5)-As(1) bond length is 3.66 Å. The Ba(5)-As(11) bond length is 3.49 Å. The Ba(5)-As(12) bond length is 3.75 Å. The Ba(5)-As(15) bond length is 3.48 Å. The Ba(5)-As(3) bond length is 3.78 Å. The Ba(5)-As(4) bond length is 3.56 Å. The Ba(5)-As(9) bond length is 3.65 Å. Both Ba(5)-As(7) bond lengths are 3.54 Å. In the sixth Ba site, Ba(6) is bonded in a 8-coordinate geometry to one As(13), one As(2), two equivalent As(14), two equivalent As(16), and two equivalent As(5) atoms. The Ba(6)-As(13) bond length is 3.45 Å. The Ba(6)-As(2) bond length is 3.41 Å. Both Ba(6)-As(14) bond lengths are 3.27 Å. Both Ba(6)-As(16) bond lengths are 3.50 Å. Both Ba(6)-As(5) bond lengths are 3.43 Å. In the seventh Ba site, Ba(7) is bonded in a 8-coordinate geometry to two equivalent As(1), two equivalent As(15), two equivalent As(16), and two equivalent As(6) atoms. Both Ba(7)-As(1) bond lengths are 3.46 Å. Both Ba(7)-As(15) bond lengths are 3.35 Å. Both Ba(7)-As(16) bond lengths are 3.42 Å. Both Ba(7)-As(6) bond lengths are 3.36 Å. In the eighth Ba site, Ba(8) is bonded in a 8-coordinate geometry to two equivalent As(14), two equivalent As(15), two equivalent As(16), and two equivalent As(3) atoms. Both Ba(8)-As(14) bond lengths are 3.40 Å. Both Ba(8)-As(15) bond lengths are 3.39 Å. Both Ba(8)-As(16) bond lengths are 3.48 Å. Both Ba(8)-As(3) bond lengths are 3.39 Å. There are sixteen inequivalent As sites. In the first As site, As(1) is bonded to one K(1), one Ba(1), one Ba(2), one Ba(5), one Ba(7), one As(10), and one As(15) atom to form a mixture of distorted face and corner-sharing AsKBa4As2 pentagonal bipyramids. The As(1)-As(10) bond length is 2.47 Å. The As(1)-As(15) bond length is 2.52 Å. In the second As site, As(2) is bonded in a 5-coordinate geometry to one K(1), one K(4), one Ba(6), and two equivalent As(3) atoms. Both As(2)-As(3) bond lengths are 2.46 Å. In the third As site, As(3) is bonded in a 7-coordinate geometry to one K(3), one Ba(1), one Ba(3), one Ba(5), one Ba(8), one As(2), and one As(5) atom. The As(3)-As(5) bond length is 2.53 Å. In the fourth As site, As(4) is bonded in a 8-coordinate geometry to one K(1), one K(2), one K(4), one Ba(2), one Ba(3), one Ba(5), one As(6), and one As(7) atom. The As(4)-As(6) bond length is 2.55 Å. The As(4)-As(7) bond length is 2.56 Å. In the fifth As site, As(5) is bonded in a 8-coordinate geometry to one K(3), one Ba(1), one Ba(2), one Ba(3), one Ba(4), one Ba(6), one As(3), and one As(8) atom. The As(5)-As(8) bond length is 2.59 Å. In the sixth As site, As(6) is bonded in a 7-coordinate geometry to one K(2), one K(4), one Ba(2), one Ba(4), one Ba(7), one As(13), and one As(4) atom. The As(6)-As(13) bond length is 2.47 Å. In the seventh As site, As(7) is bonded in a 8-coordinate geometry to two equivalent K(2), one Ba(2), one Ba(3), two equivalent Ba(5), one As(4), and one As(9) atom. The As(7)-As(9) bond length is 2.53 Å. In the eighth As site, As(8) is bonded in a 8-coordinate geometry to two equivalent K(3), one Ba(2), one Ba(3), two equivalent Ba(4), one As(12), and one As(5) atom. The As(8)-As(12) bond length is 2.53 Å. In the ninth As site, As(9) is bonded to one K(2), one Ba(4), one Ba(5), two equivalent Ba(2), one As(10), and one As(7) atom to form a mixture of distorted face and corner-sharing AsKBa4As2 pentagonal bipyramids. The As(9)-As(10) bond length is 2.46 Å. In the tenth As site, As(10) is bonded in a 5-coordinate geometry to one K(2), one K(3), one Ba(4), one As(1), and one As(9) atom. In the eleventh As site, As(11) is bonded in a 5-coordinate geometry to one K(2), one K(3), one Ba(5), one As(12), and one As(14) atom. The As(11)-As(12) bond length is 2.45 Å. The As(11)-As(14) bond length is 2.46 Å. In the twelfth As site, As(12) is bonded to one K(3), one Ba(4), one Ba(5), two equivalent Ba(3), one As(11), and one As(8) atom to form distorted corner-sharing AsKBa4As2 pentagonal bipyramids. In the thirteenth As site, As(13) is bonded in a 5-coordinate geometry to one K(1), one Ba(1), one Ba(6), and two equivalent As(6) atoms. In the fourteenth As site, As(14) is bonded in a 7-coordinate geometry to one K(4), one Ba(3), one Ba(4), one Ba(6), one Ba(8), one As(11), and one As(16) atom. The As(14)-As(16) bond length is 2.54 Å. In the fifteenth As site, As(15) is bonded in a 8-coordinate geometry to one K(1), one K(2), one K(4), one Ba(5), one Ba(7), one Ba(8), one As(1), and one As(15) atom. The As(15)-As(15) bond length is 2.58 Å. In the sixteenth As site, As(16) is bonded in a 8-coordinate geometry to one K(3), one Ba(1), one Ba(4), one Ba(6), one Ba(7), one Ba(8), one As(14), and one As(16) atom. The As(16)-As(16) bond length is 2.59 Å.