The structure described by 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. is represented by the Crystallographic Information File (CIF) [CIF]
data_LiAlSi2H2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.063
_cell_length_b   7.644
_cell_length_c   8.512
_cell_angle_alpha   68.547
_cell_angle_beta   87.728
_cell_angle_gamma   87.078
_symmetry_Int_Tables_number   1
_cell_volume   306.156
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Li  Li0  1  0.684  0.815  0.295  1.0
  Li  Li1  1  0.164  0.117  0.713  1.0
  Al  Al2  1  0.162  0.062  0.396  1.0
  Al  Al3  1  0.667  0.093  0.905  1.0
  Si  Si4  1  0.177  0.923  0.103  1.0
  Si  Si5  1  0.098  0.503  0.149  1.0
  Si  Si6  1  0.642  0.511  0.913  1.0
  Si  Si7  1  0.663  0.926  0.627  1.0
  H  H8  1  0.653  0.516  0.235  1.0
  H  H9  1  0.531  0.388  0.709  1.0
  H  H10  1  0.119  0.479  0.611  1.0
  H  H11  1  0.218  0.387  0.477  1.0
  O  O12  1  0.310  0.953  0.263  1.0
  O  O13  1  0.863  0.995  0.083  1.0
  O  O14  1  0.234  0.703  0.135  1.0
  O  O15  1  0.410  0.450  0.051  1.0
  O  O16  1  0.144  0.310  0.320  1.0
  O  O17  1  0.856  0.942  0.464  1.0
  O  O18  1  0.808  0.583  0.241  1.0
  O  O19  1  0.801  0.034  0.737  1.0
  O  O20  1  0.332  0.046  0.928  1.0
  O  O21  1  0.657  0.353  0.806  1.0
  O  O22  1  0.935  0.483  0.989  1.0
  O  O23  1  0.619  0.705  0.748  1.0
  O  O24  1  0.366  0.013  0.572  1.0
  O  O25  1  0.251  0.391  0.592  1.0
[/CIF]
.
The structure described by 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. is represented by the Crystallographic Information File (CIF) [CIF]
data_LiAlSi2H2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.063
_cell_length_b   7.644
_cell_length_c   8.512
_cell_angle_alpha   68.547
_cell_angle_beta   87.728
_cell_angle_gamma   87.078
_symmetry_Int_Tables_number   1
_cell_volume   306.156
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Li  Li0  1  0.684  0.815  0.295  1.0
  Li  Li1  1  0.164  0.117  0.713  1.0
  Al  Al2  1  0.162  0.062  0.396  1.0
  Al  Al3  1  0.667  0.093  0.905  1.0
  Si  Si4  1  0.177  0.923  0.103  1.0
  Si  Si5  1  0.098  0.503  0.149  1.0
  Si  Si6  1  0.642  0.511  0.913  1.0
  Si  Si7  1  0.663  0.926  0.627  1.0
  H  H8  1  0.653  0.516  0.235  1.0
  H  H9  1  0.531  0.388  0.709  1.0
  H  H10  1  0.119  0.479  0.611  1.0
  H  H11  1  0.218  0.387  0.477  1.0
  O  O12  1  0.310  0.953  0.263  1.0
  O  O13  1  0.863  0.995  0.083  1.0
  O  O14  1  0.234  0.703  0.135  1.0
  O  O15  1  0.410  0.450  0.051  1.0
  O  O16  1  0.144  0.310  0.320  1.0
  O  O17  1  0.856  0.942  0.464  1.0
  O  O18  1  0.808  0.583  0.241  1.0
  O  O19  1  0.801  0.034  0.737  1.0
  O  O20  1  0.332  0.046  0.928  1.0
  O  O21  1  0.657  0.353  0.806  1.0
  O  O22  1  0.935  0.483  0.989  1.0
  O  O23  1  0.619  0.705  0.748  1.0
  O  O24  1  0.366  0.013  0.572  1.0
  O  O25  1  0.251  0.391  0.592  1.0
[/CIF]
.