Fe2Al9Si4HO24 crystallizes in the monoclinic C2/m space group. Fe(1) is bonded to one O(1), one O(2), and two equivalent O(7) atoms to form FeO4 tetrahedra that share  a cornercorner with one Al(4)O6 octahedra, corners with two equivalent Al(1)O6 octahedra, corners with two equivalent Al(2)O6 octahedra, and corners with six equivalent Al(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-72°. There are four inequivalent Al sites. In the first Al site, Al(1) is bonded to two equivalent O(3), two equivalent O(6), and two equivalent O(7) atoms to form AlO6 octahedra that share corners with two equivalent Fe(1)O4 tetrahedra, corners with four equivalent Si(1)O4 tetrahedra, edges with two equivalent Al(2)O6 octahedra, and edges with two equivalent Al(3)O6 octahedra. In the second Al site, Al(2) is bonded to two equivalent O(4), two equivalent O(6), and two equivalent O(7) atoms to form AlO6 octahedra that share corners with two equivalent Fe(1)O4 tetrahedra, corners with four equivalent Si(1)O4 tetrahedra, edges with two equivalent Al(1)O6 octahedra, and edges with two equivalent Al(3)O6 octahedra. In the third Al site, Al(3) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(7) atom to form AlO6 octahedra that share corners with three equivalent Fe(1)O4 tetrahedra, corners with three equivalent Si(1)O4 tetrahedra,  an edgeedge with one Al(1)O6 octahedra,  an edgeedge with one Al(2)O6 octahedra,  an edgeedge with one Al(3)O6 octahedra, and  an edgeedge with one Al(4)O6 octahedra. In the fourth Al site, Al(4) is bonded to two equivalent O(1) and four equivalent O(5) atoms to form AlO6 octahedra that share corners with two equivalent Fe(1)O4 tetrahedra, corners with four equivalent Si(1)O4 tetrahedra, and edges with four equivalent Al(3)O6 octahedra. Si(1) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Al(4)O6 octahedra, corners with two equivalent Al(1)O6 octahedra, corners with two equivalent Al(2)O6 octahedra, and corners with three equivalent Al(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 50-55°. H(1) is bonded in a linear geometry to two equivalent O(2) atoms. There are seven inequivalent O sites. In the first O site, O(1) is bonded to one Fe(1), one Al(4), and two equivalent Al(3) atoms to form distorted OAl3Fe trigonal pyramids that share  a cornercorner with one O(2)Al2FeH tetrahedra, corners with four equivalent O(7)Al3Fe tetrahedra,  a cornercorner with one O(1)Al3Fe trigonal pyramid, and  an edgeedge with one O(2)Al2FeH tetrahedra. In the second O site, O(2) is bonded to one Fe(1), two equivalent Al(3), and one H(1) atom to form distorted OAl2FeH tetrahedra that share  a cornercorner with one O(2)Al2FeH tetrahedra, corners with four equivalent O(7)Al3Fe tetrahedra,  a cornercorner with one O(1)Al3Fe trigonal pyramid, and  an edgeedge with one O(1)Al3Fe trigonal pyramid. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Al(1), one Al(3), and one Si(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Al(2), one Al(3), and one Si(1) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Al(3), one Al(4), and one Si(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Al(1), one Al(2), and one Si(1) atom. In the seventh O site, O(7) is bonded to one Fe(1), one Al(1), one Al(2), and one Al(3) atom to form distorted OAl3Fe tetrahedra that share corners with two equivalent O(2)Al2FeH tetrahedra, corners with three equivalent O(7)Al3Fe tetrahedra, and corners with two equivalent O(1)Al3Fe trigonal pyramids.
Fe2Al9Si4HO24 crystallizes in the monoclinic C2/m space group. Fe(1) is bonded to one O(1), one O(2), and two equivalent O(7) atoms to form FeO4 tetrahedra that share  a cornercorner with one Al(4)O6 octahedra, corners with two equivalent Al(1)O6 octahedra, corners with two equivalent Al(2)O6 octahedra, and corners with six equivalent Al(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-72°. The Fe(1)-O(1) bond length is 2.05 Å. The Fe(1)-O(2) bond length is 2.10 Å. Both Fe(1)-O(7) bond lengths are 2.09 Å. There are four inequivalent Al sites. In the first Al site, Al(1) is bonded to two equivalent O(3), two equivalent O(6), and two equivalent O(7) atoms to form AlO6 octahedra that share corners with two equivalent Fe(1)O4 tetrahedra, corners with four equivalent Si(1)O4 tetrahedra, edges with two equivalent Al(2)O6 octahedra, and edges with two equivalent Al(3)O6 octahedra. Both Al(1)-O(3) bond lengths are 1.88 Å. Both Al(1)-O(6) bond lengths are 1.94 Å. Both Al(1)-O(7) bond lengths are 1.96 Å. In the second Al site, Al(2) is bonded to two equivalent O(4), two equivalent O(6), and two equivalent O(7) atoms to form AlO6 octahedra that share corners with two equivalent Fe(1)O4 tetrahedra, corners with four equivalent Si(1)O4 tetrahedra, edges with two equivalent Al(1)O6 octahedra, and edges with two equivalent Al(3)O6 octahedra. Both Al(2)-O(4) bond lengths are 1.94 Å. Both Al(2)-O(6) bond lengths are 1.92 Å. Both Al(2)-O(7) bond lengths are 1.92 Å. In the third Al site, Al(3) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(7) atom to form AlO6 octahedra that share corners with three equivalent Fe(1)O4 tetrahedra, corners with three equivalent Si(1)O4 tetrahedra,  an edgeedge with one Al(1)O6 octahedra,  an edgeedge with one Al(2)O6 octahedra,  an edgeedge with one Al(3)O6 octahedra, and  an edgeedge with one Al(4)O6 octahedra. The Al(3)-O(1) bond length is 1.93 Å. The Al(3)-O(2) bond length is 1.93 Å. The Al(3)-O(3) bond length is 2.05 Å. The Al(3)-O(4) bond length is 1.94 Å. The Al(3)-O(5) bond length is 1.85 Å. The Al(3)-O(7) bond length is 1.89 Å. In the fourth Al site, Al(4) is bonded to two equivalent O(1) and four equivalent O(5) atoms to form AlO6 octahedra that share corners with two equivalent Fe(1)O4 tetrahedra, corners with four equivalent Si(1)O4 tetrahedra, and edges with four equivalent Al(3)O6 octahedra. Both Al(4)-O(1) bond lengths are 1.82 Å. All Al(4)-O(5) bond lengths are 2.01 Å. Si(1) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Al(4)O6 octahedra, corners with two equivalent Al(1)O6 octahedra, corners with two equivalent Al(2)O6 octahedra, and corners with three equivalent Al(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 50-55°. The Si(1)-O(3) bond length is 1.65 Å. The Si(1)-O(4) bond length is 1.65 Å. The Si(1)-O(5) bond length is 1.64 Å. The Si(1)-O(6) bond length is 1.66 Å. H(1) is bonded in a linear geometry to two equivalent O(2) atoms. Both H(1)-O(2) bond lengths are 1.40 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded to one Fe(1), one Al(4), and two equivalent Al(3) atoms to form distorted OAl3Fe trigonal pyramids that share  a cornercorner with one O(2)Al2FeH tetrahedra, corners with four equivalent O(7)Al3Fe tetrahedra,  a cornercorner with one O(1)Al3Fe trigonal pyramid, and  an edgeedge with one O(2)Al2FeH tetrahedra. In the second O site, O(2) is bonded to one Fe(1), two equivalent Al(3), and one H(1) atom to form distorted OAl2FeH tetrahedra that share  a cornercorner with one O(2)Al2FeH tetrahedra, corners with four equivalent O(7)Al3Fe tetrahedra,  a cornercorner with one O(1)Al3Fe trigonal pyramid, and  an edgeedge with one O(1)Al3Fe trigonal pyramid. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Al(1), one Al(3), and one Si(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Al(2), one Al(3), and one Si(1) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Al(3), one Al(4), and one Si(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Al(1), one Al(2), and one Si(1) atom. In the seventh O site, O(7) is bonded to one Fe(1), one Al(1), one Al(2), and one Al(3) atom to form distorted OAl3Fe tetrahedra that share corners with two equivalent O(2)Al2FeH tetrahedra, corners with three equivalent O(7)Al3Fe tetrahedra, and corners with two equivalent O(1)Al3Fe trigonal pyramids.