Mo2Al2O7 crystallizes in the triclinic P1 space group. There are four inequivalent Mo sites. In the first Mo site, Mo(1) is bonded in a distorted pentagonal planar geometry to one O(14), one O(4), one O(5), one O(7), and one O(9) atom. In the second Mo site, Mo(2) is bonded to one O(10), one O(12), one O(13), one O(3), and one O(7) atom to form MoO5 trigonal bipyramids that share  a cornercorner with one Al(1)O4 tetrahedra. In the third Mo site, Mo(3) is bonded in a 6-coordinate geometry to one O(11), one O(13), one O(4), one O(6), one O(8), and one O(9) atom. In the fourth Mo site, Mo(4) is bonded in a 6-coordinate geometry to one O(11), one O(12), one O(14), one O(3), one O(5), and one O(6) atom. There are four inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(1), one O(2), one O(3), and one O(8) atom to form distorted AlO4 tetrahedra that share  a cornercorner with one Mo(2)O5 trigonal bipyramid and  a cornercorner with one Al(2)O5 trigonal bipyramid. In the second Al site, Al(2) is bonded to one O(1), one O(11), one O(4), one O(6), and one O(9) atom to form distorted corner-sharing AlO5 trigonal bipyramids. In the third Al site, Al(3) is bonded in a see-saw-like geometry to one O(10), one O(12), one O(2), and one O(5) atom. In the fourth Al site, Al(4) is bonded in a 6-coordinate geometry to one O(1), one O(10), one O(13), one O(2), one O(7), and one O(8) atom. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Al(1), one Al(2), and one Al(4) atom. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Al(1), one Al(3), and one Al(4) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Mo(2), one Mo(4), and one Al(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Mo(1), one Mo(3), and one Al(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Mo(1), one Mo(4), and one Al(3) atom. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Mo(3), one Mo(4), and one Al(2) atom. In the seventh O site, O(7) is bonded in a trigonal planar geometry to one Mo(1), one Mo(2), and one Al(4) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Mo(3), one Al(1), and one Al(4) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Mo(1), one Mo(3), and one Al(2) atom. In the tenth O site, O(10) is bonded in a distorted trigonal planar geometry to one Mo(2), one Al(3), and one Al(4) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Mo(3), one Mo(4), and one Al(2) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Mo(2), one Mo(4), and one Al(3) atom. In the thirteenth O site, O(13) is bonded in a trigonal planar geometry to one Mo(2), one Mo(3), and one Al(4) atom. In the fourteenth O site, O(14) is bonded in a water-like geometry to one Mo(1) and one Mo(4) atom.
Mo2Al2O7 crystallizes in the triclinic P1 space group. There are four inequivalent Mo sites. In the first Mo site, Mo(1) is bonded in a distorted pentagonal planar geometry to one O(14), one O(4), one O(5), one O(7), and one O(9) atom. The Mo(1)-O(14) bond length is 1.94 Å. The Mo(1)-O(4) bond length is 1.93 Å. The Mo(1)-O(5) bond length is 2.07 Å. The Mo(1)-O(7) bond length is 2.02 Å. The Mo(1)-O(9) bond length is 1.97 Å. In the second Mo site, Mo(2) is bonded to one O(10), one O(12), one O(13), one O(3), and one O(7) atom to form MoO5 trigonal bipyramids that share  a cornercorner with one Al(1)O4 tetrahedra. The Mo(2)-O(10) bond length is 2.07 Å. The Mo(2)-O(12) bond length is 2.03 Å. The Mo(2)-O(13) bond length is 2.10 Å. The Mo(2)-O(3) bond length is 2.00 Å. The Mo(2)-O(7) bond length is 2.01 Å. In the third Mo site, Mo(3) is bonded in a 6-coordinate geometry to one O(11), one O(13), one O(4), one O(6), one O(8), and one O(9) atom. The Mo(3)-O(11) bond length is 2.23 Å. The Mo(3)-O(13) bond length is 1.97 Å. The Mo(3)-O(4) bond length is 2.11 Å. The Mo(3)-O(6) bond length is 2.02 Å. The Mo(3)-O(8) bond length is 2.03 Å. The Mo(3)-O(9) bond length is 2.17 Å. In the fourth Mo site, Mo(4) is bonded in a 6-coordinate geometry to one O(11), one O(12), one O(14), one O(3), one O(5), and one O(6) atom. The Mo(4)-O(11) bond length is 2.01 Å. The Mo(4)-O(12) bond length is 2.26 Å. The Mo(4)-O(14) bond length is 1.93 Å. The Mo(4)-O(3) bond length is 2.23 Å. The Mo(4)-O(5) bond length is 1.99 Å. The Mo(4)-O(6) bond length is 2.19 Å. There are four inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(1), one O(2), one O(3), and one O(8) atom to form distorted AlO4 tetrahedra that share  a cornercorner with one Mo(2)O5 trigonal bipyramid and  a cornercorner with one Al(2)O5 trigonal bipyramid. The Al(1)-O(1) bond length is 1.83 Å. The Al(1)-O(2) bond length is 1.76 Å. The Al(1)-O(3) bond length is 1.80 Å. The Al(1)-O(8) bond length is 1.82 Å. In the second Al site, Al(2) is bonded to one O(1), one O(11), one O(4), one O(6), and one O(9) atom to form distorted corner-sharing AlO5 trigonal bipyramids. The Al(2)-O(1) bond length is 1.79 Å. The Al(2)-O(11) bond length is 1.84 Å. The Al(2)-O(4) bond length is 2.29 Å. The Al(2)-O(6) bond length is 1.83 Å. The Al(2)-O(9) bond length is 1.88 Å. In the third Al site, Al(3) is bonded in a see-saw-like geometry to one O(10), one O(12), one O(2), and one O(5) atom. The Al(3)-O(10) bond length is 1.87 Å. The Al(3)-O(12) bond length is 1.86 Å. The Al(3)-O(2) bond length is 1.74 Å. The Al(3)-O(5) bond length is 1.84 Å. In the fourth Al site, Al(4) is bonded in a 6-coordinate geometry to one O(1), one O(10), one O(13), one O(2), one O(7), and one O(8) atom. The Al(4)-O(1) bond length is 1.92 Å. The Al(4)-O(10) bond length is 2.00 Å. The Al(4)-O(13) bond length is 1.91 Å. The Al(4)-O(2) bond length is 2.39 Å. The Al(4)-O(7) bond length is 1.96 Å. The Al(4)-O(8) bond length is 1.88 Å. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Al(1), one Al(2), and one Al(4) atom. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Al(1), one Al(3), and one Al(4) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Mo(2), one Mo(4), and one Al(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Mo(1), one Mo(3), and one Al(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Mo(1), one Mo(4), and one Al(3) atom. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Mo(3), one Mo(4), and one Al(2) atom. In the seventh O site, O(7) is bonded in a trigonal planar geometry to one Mo(1), one Mo(2), and one Al(4) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Mo(3), one Al(1), and one Al(4) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Mo(1), one Mo(3), and one Al(2) atom. In the tenth O site, O(10) is bonded in a distorted trigonal planar geometry to one Mo(2), one Al(3), and one Al(4) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Mo(3), one Mo(4), and one Al(2) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Mo(2), one Mo(4), and one Al(3) atom. In the thirteenth O site, O(13) is bonded in a trigonal planar geometry to one Mo(2), one Mo(3), and one Al(4) atom. In the fourteenth O site, O(14) is bonded in a water-like geometry to one Mo(1) and one Mo(4) atom.