Cu2Al6B4O17 crystallizes in the monoclinic Cm space group. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(13), one O(5), one O(8), and two equivalent O(10) atoms to form CuO5 trigonal bipyramids that share corners with two equivalent Al(2)O6 octahedra,  a cornercorner with one Al(3)O5 trigonal bipyramid, edges with two equivalent Al(1)O6 octahedra,  an edgeedge with one Cu(2)O5 trigonal bipyramid, and  an edgeedge with one Al(4)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 55°. In the second Cu site, Cu(2) is bonded to one O(13), one O(5), one O(7), and two equivalent O(12) atoms to form distorted CuO5 trigonal bipyramids that share corners with two equivalent Al(1)O6 octahedra,  a cornercorner with one Al(4)O5 trigonal bipyramid, edges with two equivalent Al(2)O6 octahedra,  an edgeedge with one Cu(1)O5 trigonal bipyramid, and  an edgeedge with one Al(3)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 52°. There are four inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(1), one O(10), one O(2), one O(5), one O(6), and one O(9) atom to form AlO6 octahedra that share  a cornercorner with one Cu(2)O5 trigonal bipyramid,  a cornercorner with one Al(4)O5 trigonal bipyramid, edges with two equivalent Al(1)O6 octahedra,  an edgeedge with one Cu(1)O5 trigonal bipyramid, and  an edgeedge with one Al(3)O5 trigonal bipyramid. In the second Al site, Al(2) is bonded to one O(11), one O(12), one O(3), one O(4), one O(7), and one O(8) atom to form AlO6 octahedra that share  a cornercorner with one Cu(1)O5 trigonal bipyramid,  a cornercorner with one Al(3)O5 trigonal bipyramid, edges with two equivalent Al(2)O6 octahedra,  an edgeedge with one Cu(2)O5 trigonal bipyramid, and  an edgeedge with one Al(4)O5 trigonal bipyramid. In the third Al site, Al(3) is bonded to one O(13), one O(6), one O(7), and two equivalent O(9) atoms to form AlO5 trigonal bipyramids that share corners with two equivalent Al(2)O6 octahedra,  a cornercorner with one Cu(1)O5 trigonal bipyramid, edges with two equivalent Al(1)O6 octahedra,  an edgeedge with one Cu(2)O5 trigonal bipyramid, and  an edgeedge with one Al(4)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 50°. In the fourth Al site, Al(4) is bonded to one O(13), one O(6), one O(8), and two equivalent O(11) atoms to form AlO5 trigonal bipyramids that share corners with two equivalent Al(1)O6 octahedra,  a cornercorner with one Cu(2)O5 trigonal bipyramid, edges with two equivalent Al(2)O6 octahedra,  an edgeedge with one Cu(1)O5 trigonal bipyramid, and  an edgeedge with one Al(3)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 51°. There are four inequivalent B sites. In the first B site, B(1) is bonded in a trigonal planar geometry to one O(1) and two equivalent O(11) atoms. In the second B site, B(2) is bonded in a trigonal planar geometry to one O(2) and two equivalent O(12) atoms. In the third B site, B(3) is bonded in a trigonal planar geometry to one O(3) and two equivalent O(10) atoms. In the fourth B site, B(4) is bonded in a trigonal planar geometry to one O(4) and two equivalent O(9) atoms. There are thirteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to two equivalent Al(1) and one B(1) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to two equivalent Al(1) and one B(2) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to two equivalent Al(2) and one B(3) atom. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to two equivalent Al(2) and one B(4) atom. In the fifth O site, O(5) is bonded to one Cu(1), one Cu(2), and two equivalent Al(1) atoms to form OAl2Cu2 trigonal pyramids that share  a cornercorner with one O(7)Al3Cu trigonal pyramid,  a cornercorner with one O(8)Al3Cu trigonal pyramid, and corners with two equivalent O(6)Al4 trigonal pyramids. In the sixth O site, O(6) is bonded to one Al(3), one Al(4), and two equivalent Al(1) atoms to form OAl4 trigonal pyramids that share  a cornercorner with one O(7)Al3Cu trigonal pyramid,  a cornercorner with one O(8)Al3Cu trigonal pyramid, and corners with two equivalent O(5)Al2Cu2 trigonal pyramids. In the seventh O site, O(7) is bonded to one Cu(2), one Al(3), and two equivalent Al(2) atoms to form OAl3Cu trigonal pyramids that share  a cornercorner with one O(5)Al2Cu2 trigonal pyramid,  a cornercorner with one O(6)Al4 trigonal pyramid, and corners with two equivalent O(8)Al3Cu trigonal pyramids. In the eighth O site, O(8) is bonded to one Cu(1), one Al(4), and two equivalent Al(2) atoms to form OAl3Cu trigonal pyramids that share  a cornercorner with one O(5)Al2Cu2 trigonal pyramid,  a cornercorner with one O(6)Al4 trigonal pyramid, and corners with two equivalent O(7)Al3Cu trigonal pyramids. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Al(1), one Al(3), and one B(4) atom. In the tenth O site, O(10) is bonded in a distorted trigonal planar geometry to one Cu(1), one Al(1), and one B(3) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one Al(2), one Al(4), and one B(1) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal planar geometry to one Cu(2), one Al(2), and one B(2) atom. In the thirteenth O site, O(13) is bonded in a distorted rectangular see-saw-like geometry to one Cu(1), one Cu(2), one Al(3), and one Al(4) atom.
Cu2Al6B4O17 crystallizes in the monoclinic Cm space group. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(13), one O(5), one O(8), and two equivalent O(10) atoms to form CuO5 trigonal bipyramids that share corners with two equivalent Al(2)O6 octahedra,  a cornercorner with one Al(3)O5 trigonal bipyramid, edges with two equivalent Al(1)O6 octahedra,  an edgeedge with one Cu(2)O5 trigonal bipyramid, and  an edgeedge with one Al(4)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 55°. The Cu(1)-O(13) bond length is 2.28 Å. The Cu(1)-O(5) bond length is 2.01 Å. The Cu(1)-O(8) bond length is 1.91 Å. Both Cu(1)-O(10) bond lengths are 1.96 Å. In the second Cu site, Cu(2) is bonded to one O(13), one O(5), one O(7), and two equivalent O(12) atoms to form distorted CuO5 trigonal bipyramids that share corners with two equivalent Al(1)O6 octahedra,  a cornercorner with one Al(4)O5 trigonal bipyramid, edges with two equivalent Al(2)O6 octahedra,  an edgeedge with one Cu(1)O5 trigonal bipyramid, and  an edgeedge with one Al(3)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 52°. The Cu(2)-O(13) bond length is 2.22 Å. The Cu(2)-O(5) bond length is 1.88 Å. The Cu(2)-O(7) bond length is 2.09 Å. Both Cu(2)-O(12) bond lengths are 1.96 Å. There are four inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(1), one O(10), one O(2), one O(5), one O(6), and one O(9) atom to form AlO6 octahedra that share  a cornercorner with one Cu(2)O5 trigonal bipyramid,  a cornercorner with one Al(4)O5 trigonal bipyramid, edges with two equivalent Al(1)O6 octahedra,  an edgeedge with one Cu(1)O5 trigonal bipyramid, and  an edgeedge with one Al(3)O5 trigonal bipyramid. The Al(1)-O(1) bond length is 1.95 Å. The Al(1)-O(10) bond length is 1.89 Å. The Al(1)-O(2) bond length is 1.96 Å. The Al(1)-O(5) bond length is 1.85 Å. The Al(1)-O(6) bond length is 1.87 Å. The Al(1)-O(9) bond length is 2.00 Å. In the second Al site, Al(2) is bonded to one O(11), one O(12), one O(3), one O(4), one O(7), and one O(8) atom to form AlO6 octahedra that share  a cornercorner with one Cu(1)O5 trigonal bipyramid,  a cornercorner with one Al(3)O5 trigonal bipyramid, edges with two equivalent Al(2)O6 octahedra,  an edgeedge with one Cu(2)O5 trigonal bipyramid, and  an edgeedge with one Al(4)O5 trigonal bipyramid. The Al(2)-O(11) bond length is 1.99 Å. The Al(2)-O(12) bond length is 1.89 Å. The Al(2)-O(3) bond length is 1.93 Å. The Al(2)-O(4) bond length is 1.98 Å. The Al(2)-O(7) bond length is 1.88 Å. The Al(2)-O(8) bond length is 1.85 Å. In the third Al site, Al(3) is bonded to one O(13), one O(6), one O(7), and two equivalent O(9) atoms to form AlO5 trigonal bipyramids that share corners with two equivalent Al(2)O6 octahedra,  a cornercorner with one Cu(1)O5 trigonal bipyramid, edges with two equivalent Al(1)O6 octahedra,  an edgeedge with one Cu(2)O5 trigonal bipyramid, and  an edgeedge with one Al(4)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 50°. The Al(3)-O(13) bond length is 1.79 Å. The Al(3)-O(6) bond length is 2.02 Å. The Al(3)-O(7) bond length is 1.82 Å. Both Al(3)-O(9) bond lengths are 1.87 Å. In the fourth Al site, Al(4) is bonded to one O(13), one O(6), one O(8), and two equivalent O(11) atoms to form AlO5 trigonal bipyramids that share corners with two equivalent Al(1)O6 octahedra,  a cornercorner with one Cu(2)O5 trigonal bipyramid, edges with two equivalent Al(2)O6 octahedra,  an edgeedge with one Cu(1)O5 trigonal bipyramid, and  an edgeedge with one Al(3)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 51°. The Al(4)-O(13) bond length is 1.80 Å. The Al(4)-O(6) bond length is 1.85 Å. The Al(4)-O(8) bond length is 1.91 Å. Both Al(4)-O(11) bond lengths are 1.88 Å. There are four inequivalent B sites. In the first B site, B(1) is bonded in a trigonal planar geometry to one O(1) and two equivalent O(11) atoms. The B(1)-O(1) bond length is 1.36 Å. Both B(1)-O(11) bond lengths are 1.40 Å. In the second B site, B(2) is bonded in a trigonal planar geometry to one O(2) and two equivalent O(12) atoms. The B(2)-O(2) bond length is 1.39 Å. Both B(2)-O(12) bond lengths are 1.37 Å. In the third B site, B(3) is bonded in a trigonal planar geometry to one O(3) and two equivalent O(10) atoms. The B(3)-O(3) bond length is 1.39 Å. Both B(3)-O(10) bond lengths are 1.37 Å. In the fourth B site, B(4) is bonded in a trigonal planar geometry to one O(4) and two equivalent O(9) atoms. The B(4)-O(4) bond length is 1.37 Å. Both B(4)-O(9) bond lengths are 1.40 Å. There are thirteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to two equivalent Al(1) and one B(1) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to two equivalent Al(1) and one B(2) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to two equivalent Al(2) and one B(3) atom. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to two equivalent Al(2) and one B(4) atom. In the fifth O site, O(5) is bonded to one Cu(1), one Cu(2), and two equivalent Al(1) atoms to form OAl2Cu2 trigonal pyramids that share  a cornercorner with one O(7)Al3Cu trigonal pyramid,  a cornercorner with one O(8)Al3Cu trigonal pyramid, and corners with two equivalent O(6)Al4 trigonal pyramids. In the sixth O site, O(6) is bonded to one Al(3), one Al(4), and two equivalent Al(1) atoms to form OAl4 trigonal pyramids that share  a cornercorner with one O(7)Al3Cu trigonal pyramid,  a cornercorner with one O(8)Al3Cu trigonal pyramid, and corners with two equivalent O(5)Al2Cu2 trigonal pyramids. In the seventh O site, O(7) is bonded to one Cu(2), one Al(3), and two equivalent Al(2) atoms to form OAl3Cu trigonal pyramids that share  a cornercorner with one O(5)Al2Cu2 trigonal pyramid,  a cornercorner with one O(6)Al4 trigonal pyramid, and corners with two equivalent O(8)Al3Cu trigonal pyramids. In the eighth O site, O(8) is bonded to one Cu(1), one Al(4), and two equivalent Al(2) atoms to form OAl3Cu trigonal pyramids that share  a cornercorner with one O(5)Al2Cu2 trigonal pyramid,  a cornercorner with one O(6)Al4 trigonal pyramid, and corners with two equivalent O(7)Al3Cu trigonal pyramids. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Al(1), one Al(3), and one B(4) atom. In the tenth O site, O(10) is bonded in a distorted trigonal planar geometry to one Cu(1), one Al(1), and one B(3) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one Al(2), one Al(4), and one B(1) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal planar geometry to one Cu(2), one Al(2), and one B(2) atom. In the thirteenth O site, O(13) is bonded in a distorted rectangular see-saw-like geometry to one Cu(1), one Cu(2), one Al(3), and one Al(4) atom.