LiAlSi2H2O7 crystallizes in the triclinic P1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(1), one O(2), one O(6), and one O(7) atom to form LiO4 trigonal pyramids that share  a cornercorner with one Al(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, corners with two equivalent Al(1)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, and  a cornercorner with one Si(2)O5 trigonal bipyramid. In the second Li site, Li(2) is bonded to one O(13), one O(14), one O(8), and one O(9) atom to form LiO4 tetrahedra that share  a cornercorner with one Al(1)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Al(2)O4 tetrahedra, and corners with two equivalent Si(4)O4 tetrahedra. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(1), one O(13), one O(5), and one O(6) atom to form AlO4 tetrahedra that share  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra,  a cornercorner with one Si(2)O5 trigonal bipyramid, and corners with two equivalent Li(1)O4 trigonal pyramids. In the second Al site, Al(2) is bonded to one O(10), one O(2), one O(8), and one O(9) atom to form AlO4 tetrahedra that share  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, and  a cornercorner with one Li(1)O4 trigonal pyramid. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(3), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one Al(1)O4 tetrahedra, corners with two equivalent Al(2)O4 tetrahedra,  a cornercorner with one Si(2)O5 trigonal bipyramid, and corners with two equivalent Li(1)O4 trigonal pyramids. In the second Si site, Si(2) is bonded to one O(11), one O(3), one O(4), one O(5), and one O(7) atom to form SiO5 trigonal bipyramids that share  a cornercorner with one Al(1)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, and  a cornercorner with one Li(1)O4 trigonal pyramid. In the third Si site, Si(3) is bonded to one O(10), one O(11), one O(12), and one O(4) atom to form SiO4 tetrahedra that share  a cornercorner with one Al(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and corners with two equivalent Si(2)O5 trigonal bipyramids. In the fourth Si site, Si(4) is bonded to one O(12), one O(13), one O(6), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Al(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent Al(1)O4 tetrahedra, and  a cornercorner with one Li(1)O4 trigonal pyramid. There are four inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(7) atom. In the second H site, H(2) is bonded in a single-bond geometry to one O(10) atom. In the third H site, H(3) is bonded in a single-bond geometry to one O(14) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one O(14) and one O(5) atom. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Li(1), one Al(1), and one Si(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Li(1), one Al(2), and one Si(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(3) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Al(1), one Si(2), and one H(4) atom. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Li(1), one Al(1), and one Si(4) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Li(1), one Si(2), and one H(1) atom. In the eighth O site, O(8) is bonded in a trigonal planar geometry to one Li(2), one Al(2), and one Si(4) atom. In the ninth O site, O(9) is bonded in a trigonal planar geometry to one Li(2), one Al(2), and one Si(1) atom. In the tenth O site, O(10) is bonded in a distorted trigonal non-coplanar geometry to one Al(2), one Si(3), and one H(2) atom. In the eleventh O site, O(11) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(3) atom. In the twelfth O site, O(12) is bonded in a bent 150 degrees geometry to one Si(3) and one Si(4) atom. In the thirteenth O site, O(13) is bonded in a trigonal planar geometry to one Li(2), one Al(1), and one Si(4) atom. In the fourteenth O site, O(14) is bonded in a distorted water-like geometry to one Li(2), one H(3), and one H(4) atom.
LiAlSi2H2O7 crystallizes in the triclinic P1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(1), one O(2), one O(6), and one O(7) atom to form LiO4 trigonal pyramids that share  a cornercorner with one Al(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, corners with two equivalent Al(1)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, and  a cornercorner with one Si(2)O5 trigonal bipyramid. The Li(1)-O(1) bond length is 2.10 Å. The Li(1)-O(2) bond length is 2.04 Å. The Li(1)-O(6) bond length is 2.24 Å. The Li(1)-O(7) bond length is 2.05 Å. In the second Li site, Li(2) is bonded to one O(13), one O(14), one O(8), and one O(9) atom to form LiO4 tetrahedra that share  a cornercorner with one Al(1)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Al(2)O4 tetrahedra, and corners with two equivalent Si(4)O4 tetrahedra. The Li(2)-O(13) bond length is 1.91 Å. The Li(2)-O(14) bond length is 2.03 Å. The Li(2)-O(8) bond length is 1.96 Å. The Li(2)-O(9) bond length is 1.93 Å. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(1), one O(13), one O(5), and one O(6) atom to form AlO4 tetrahedra that share  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra,  a cornercorner with one Si(2)O5 trigonal bipyramid, and corners with two equivalent Li(1)O4 trigonal pyramids. The Al(1)-O(1) bond length is 1.76 Å. The Al(1)-O(13) bond length is 1.77 Å. The Al(1)-O(5) bond length is 1.76 Å. The Al(1)-O(6) bond length is 1.81 Å. In the second Al site, Al(2) is bonded to one O(10), one O(2), one O(8), and one O(9) atom to form AlO4 tetrahedra that share  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, and  a cornercorner with one Li(1)O4 trigonal pyramid. The Al(2)-O(10) bond length is 1.85 Å. The Al(2)-O(2) bond length is 1.74 Å. The Al(2)-O(8) bond length is 1.76 Å. The Al(2)-O(9) bond length is 1.74 Å. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(3), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one Al(1)O4 tetrahedra, corners with two equivalent Al(2)O4 tetrahedra,  a cornercorner with one Si(2)O5 trigonal bipyramid, and corners with two equivalent Li(1)O4 trigonal pyramids. The Si(1)-O(1) bond length is 1.63 Å. The Si(1)-O(2) bond length is 1.65 Å. The Si(1)-O(3) bond length is 1.61 Å. The Si(1)-O(9) bond length is 1.64 Å. In the second Si site, Si(2) is bonded to one O(11), one O(3), one O(4), one O(5), and one O(7) atom to form SiO5 trigonal bipyramids that share  a cornercorner with one Al(1)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, and  a cornercorner with one Li(1)O4 trigonal pyramid. The Si(2)-O(11) bond length is 1.68 Å. The Si(2)-O(3) bond length is 1.67 Å. The Si(2)-O(4) bond length is 1.86 Å. The Si(2)-O(5) bond length is 1.67 Å. The Si(2)-O(7) bond length is 1.82 Å. In the third Si site, Si(3) is bonded to one O(10), one O(11), one O(12), and one O(4) atom to form SiO4 tetrahedra that share  a cornercorner with one Al(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and corners with two equivalent Si(2)O5 trigonal bipyramids. The Si(3)-O(10) bond length is 1.76 Å. The Si(3)-O(11) bond length is 1.62 Å. The Si(3)-O(12) bond length is 1.63 Å. The Si(3)-O(4) bond length is 1.59 Å. In the fourth Si site, Si(4) is bonded to one O(12), one O(13), one O(6), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Al(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent Al(1)O4 tetrahedra, and  a cornercorner with one Li(1)O4 trigonal pyramid. The Si(4)-O(12) bond length is 1.64 Å. The Si(4)-O(13) bond length is 1.63 Å. The Si(4)-O(6) bond length is 1.64 Å. The Si(4)-O(8) bond length is 1.65 Å. There are four inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(7) atom. The H(1)-O(7) bond length is 0.97 Å. In the second H site, H(2) is bonded in a single-bond geometry to one O(10) atom. The H(2)-O(10) bond length is 1.01 Å. In the third H site, H(3) is bonded in a single-bond geometry to one O(14) atom. The H(3)-O(14) bond length is 0.97 Å. In the fourth H site, H(4) is bonded in a single-bond geometry to one O(14) and one O(5) atom. The H(4)-O(14) bond length is 1.02 Å. The H(4)-O(5) bond length is 1.71 Å. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Li(1), one Al(1), and one Si(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Li(1), one Al(2), and one Si(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(3) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Al(1), one Si(2), and one H(4) atom. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Li(1), one Al(1), and one Si(4) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Li(1), one Si(2), and one H(1) atom. In the eighth O site, O(8) is bonded in a trigonal planar geometry to one Li(2), one Al(2), and one Si(4) atom. In the ninth O site, O(9) is bonded in a trigonal planar geometry to one Li(2), one Al(2), and one Si(1) atom. In the tenth O site, O(10) is bonded in a distorted trigonal non-coplanar geometry to one Al(2), one Si(3), and one H(2) atom. In the eleventh O site, O(11) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(3) atom. In the twelfth O site, O(12) is bonded in a bent 150 degrees geometry to one Si(3) and one Si(4) atom. In the thirteenth O site, O(13) is bonded in a trigonal planar geometry to one Li(2), one Al(1), and one Si(4) atom. In the fourteenth O site, O(14) is bonded in a distorted water-like geometry to one Li(2), one H(3), and one H(4) atom.