The structure described by LiAlSi2O6 crystallizes in the triclinic P1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded in a trigonal non-coplanar geometry to one O(3), one O(7), and one O(8) atom. In the second Li site, Li(2) is bonded in a trigonal planar geometry to one O(11), one O(12), and one O(5) atom. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(11), one O(12), one O(2), and one O(7) atom to form AlO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and corners with two equivalent Si(4)O4 tetrahedra. In the second Al site, Al(2) is bonded to one O(3), one O(4), one O(5), and one O(8) atom to form AlO4 tetrahedra that share  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and corners with two equivalent Si(2)O4 tetrahedra. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(6), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Al(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and corners with two equivalent Si(3)O4 tetrahedra. In the second Si site, Si(2) is bonded to one O(12), one O(3), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Al(1)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra, and corners with two equivalent Al(2)O4 tetrahedra. In the third Si site, Si(3) is bonded to one O(1), one O(10), one O(4), and one O(9) 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(1)O4 tetrahedra. In the fourth Si site, Si(4) is bonded to one O(10), one O(11), one O(7), 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, and corners with two equivalent Al(1)O4 tetrahedra. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(3) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Al(1) and one Si(1) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Li(1), one Al(2), and one Si(2) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Al(2) and one Si(3) atom. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Li(2), one Al(2), and one Si(2) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the seventh O site, O(7) is bonded in a trigonal planar geometry to one Li(1), one Al(1), and one Si(4) atom. In the eighth O site, O(8) is bonded in a trigonal planar geometry to one Li(1), one Al(2), and one Si(4) atom. In the ninth O site, O(9) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(3) atom. In the tenth O site, O(10) is bonded in a bent 150 degrees geometry to one Si(3) and one Si(4) atom. In the eleventh O site, O(11) is bonded in a trigonal planar geometry to one Li(2), one Al(1), and one Si(4) atom. In the twelfth O site, O(12) is bonded in a trigonal planar geometry to one Li(2), one Al(1), and one Si(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_LiAl(SiO3)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.039
_cell_length_b   7.701
_cell_length_c   8.705
_cell_angle_alpha   114.101
_cell_angle_beta   90.068
_cell_angle_gamma   90.146
_symmetry_Int_Tables_number   1
_cell_volume   308.346
_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  0.361  0.892  0.710  1.0
  Li  Li1  1  0.865  0.071  0.280  1.0
  Al  Al2  1  0.355  0.089  0.104  1.0
  Al  Al3  1  0.871  0.065  0.622  1.0
  Si  Si4  1  0.312  0.508  0.115  1.0
  Si  Si5  1  0.372  0.928  0.383  1.0
  Si  Si6  1  0.816  0.494  0.898  1.0
  Si  Si7  1  0.854  0.899  0.894  1.0
  O  O8  1  0.018  0.550  0.059  1.0
  O  O9  1  0.307  0.330  0.167  1.0
  O  O10  1  0.189  0.965  0.550  1.0
  O  O11  1  0.903  0.306  0.741  1.0
  O  O12  1  0.669  0.020  0.443  1.0
  O  O13  1  0.405  0.699  0.278  1.0
  O  O14  1  0.172  0.954  0.917  1.0
  O  O15  1  0.732  0.945  0.740  1.0
  O  O16  1  0.517  0.471  0.960  1.0
  O  O17  1  0.811  0.672  0.840  1.0
  O  O18  1  0.695  0.022  0.070  1.0
  O  O19  1  0.236  0.028  0.268  1.0
[/CIF]
.
The structure described by LiAlSi2O6 crystallizes in the triclinic P1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded in a trigonal non-coplanar geometry to one O(3), one O(7), and one O(8) atom. In the second Li site, Li(2) is bonded in a trigonal planar geometry to one O(11), one O(12), and one O(5) atom. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(11), one O(12), one O(2), and one O(7) atom to form AlO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and corners with two equivalent Si(4)O4 tetrahedra. In the second Al site, Al(2) is bonded to one O(3), one O(4), one O(5), and one O(8) atom to form AlO4 tetrahedra that share  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and corners with two equivalent Si(2)O4 tetrahedra. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(6), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Al(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and corners with two equivalent Si(3)O4 tetrahedra. In the second Si site, Si(2) is bonded to one O(12), one O(3), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Al(1)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra, and corners with two equivalent Al(2)O4 tetrahedra. In the third Si site, Si(3) is bonded to one O(1), one O(10), one O(4), and one O(9) 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(1)O4 tetrahedra. In the fourth Si site, Si(4) is bonded to one O(10), one O(11), one O(7), 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, and corners with two equivalent Al(1)O4 tetrahedra. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(3) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Al(1) and one Si(1) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Li(1), one Al(2), and one Si(2) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Al(2) and one Si(3) atom. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Li(2), one Al(2), and one Si(2) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the seventh O site, O(7) is bonded in a trigonal planar geometry to one Li(1), one Al(1), and one Si(4) atom. In the eighth O site, O(8) is bonded in a trigonal planar geometry to one Li(1), one Al(2), and one Si(4) atom. In the ninth O site, O(9) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(3) atom. In the tenth O site, O(10) is bonded in a bent 150 degrees geometry to one Si(3) and one Si(4) atom. In the eleventh O site, O(11) is bonded in a trigonal planar geometry to one Li(2), one Al(1), and one Si(4) atom. In the twelfth O site, O(12) is bonded in a trigonal planar geometry to one Li(2), one Al(1), and one Si(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_LiAl(SiO3)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.039
_cell_length_b   7.701
_cell_length_c   8.705
_cell_angle_alpha   114.101
_cell_angle_beta   90.068
_cell_angle_gamma   90.146
_symmetry_Int_Tables_number   1
_cell_volume   308.346
_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  0.361  0.892  0.710  1.0
  Li  Li1  1  0.865  0.071  0.280  1.0
  Al  Al2  1  0.355  0.089  0.104  1.0
  Al  Al3  1  0.871  0.065  0.622  1.0
  Si  Si4  1  0.312  0.508  0.115  1.0
  Si  Si5  1  0.372  0.928  0.383  1.0
  Si  Si6  1  0.816  0.494  0.898  1.0
  Si  Si7  1  0.854  0.899  0.894  1.0
  O  O8  1  0.018  0.550  0.059  1.0
  O  O9  1  0.307  0.330  0.167  1.0
  O  O10  1  0.189  0.965  0.550  1.0
  O  O11  1  0.903  0.306  0.741  1.0
  O  O12  1  0.669  0.020  0.443  1.0
  O  O13  1  0.405  0.699  0.278  1.0
  O  O14  1  0.172  0.954  0.917  1.0
  O  O15  1  0.732  0.945  0.740  1.0
  O  O16  1  0.517  0.471  0.960  1.0
  O  O17  1  0.811  0.672  0.840  1.0
  O  O18  1  0.695  0.022  0.070  1.0
  O  O19  1  0.236  0.028  0.268  1.0
[/CIF]
.