The compound described by Li2MgSiO4 is beta beryllia-derived structured and crystallizes in the monoclinic P2_1/c 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(3), and one O(4) atom to form LiO4 tetrahedra that share corners with two equivalent Li(2)O4 tetrahedra, corners with four equivalent Mg(1)O4 tetrahedra, corners with four equivalent Si(1)O4 tetrahedra, and  an edgeedge with one Li(2)O4 tetrahedra. In the second Li site, Li(2) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form LiO4 tetrahedra that share corners with two equivalent Li(1)O4 tetrahedra, corners with two equivalent Mg(1)O4 tetrahedra, corners with four equivalent Si(1)O4 tetrahedra,  an edgeedge with one Li(1)O4 tetrahedra, and  an edgeedge with one Mg(1)O4 tetrahedra. Mg(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form MgO4 tetrahedra that share corners with two equivalent Li(2)O4 tetrahedra, corners with four equivalent Li(1)O4 tetrahedra, corners with four equivalent Si(1)O4 tetrahedra, and  an edgeedge with one Li(2)O4 tetrahedra. Si(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SiO4 tetrahedra that share corners with four equivalent Li(1)O4 tetrahedra, corners with four equivalent Li(2)O4 tetrahedra, and corners with four equivalent Mg(1)O4 tetrahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Li(1), one Li(2), one Mg(1), and one Si(1) atom to form a mixture of corner and edge-sharing OLi2MgSi tetrahedra. In the second O site, O(2) is bonded to one Li(1), one Li(2), one Mg(1), and one Si(1) atom to form corner-sharing OLi2MgSi tetrahedra. In the third O site, O(3) is bonded to one Li(1), one Li(2), one Mg(1), and one Si(1) atom to form a mixture of corner and edge-sharing OLi2MgSi tetrahedra. In the fourth O site, O(4) is bonded to one Li(1), one Li(2), one Mg(1), and one Si(1) atom to form a mixture of distorted corner and edge-sharing OLi2MgSi trigonal pyramids. is represented by the CIF card [CIF]
data_Li2MgSiO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.802
_cell_length_b   5.071
_cell_length_c   8.102
_cell_angle_alpha   51.706
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   348.296
_cell_formula_units_Z   4
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  0.838  0.689  0.004  1.0
  Li  Li1  1  0.338  0.311  0.496  1.0
  Li  Li2  1  0.162  0.311  0.996  1.0
  Li  Li3  1  0.662  0.689  0.504  1.0
  Li  Li4  1  0.926  0.533  0.763  1.0
  Li  Li5  1  0.426  0.467  0.737  1.0
  Li  Li6  1  0.074  0.467  0.237  1.0
  Li  Li7  1  0.574  0.533  0.263  1.0
  Mg  Mg8  1  0.836  0.191  0.502  1.0
  Mg  Mg9  1  0.164  0.809  0.498  1.0
  Mg  Mg10  1  0.664  0.191  0.002  1.0
  Mg  Mg11  1  0.336  0.809  0.998  1.0
  Si  Si12  1  0.087  0.063  0.748  1.0
  Si  Si13  1  0.413  0.063  0.248  1.0
  Si  Si14  1  0.913  0.937  0.252  1.0
  Si  Si15  1  0.587  0.937  0.752  1.0
  O  O16  1  0.161  0.747  0.959  1.0
  O  O17  1  0.839  0.253  0.041  1.0
  O  O18  1  0.339  0.747  0.459  1.0
  O  O19  1  0.591  0.607  0.755  1.0
  O  O20  1  0.661  0.253  0.541  1.0
  O  O21  1  0.841  0.833  0.466  1.0
  O  O22  1  0.341  0.167  0.034  1.0
  O  O23  1  0.159  0.167  0.534  1.0
  O  O24  1  0.443  0.045  0.749  1.0
  O  O25  1  0.091  0.393  0.745  1.0
  O  O26  1  0.409  0.393  0.245  1.0
  O  O27  1  0.909  0.607  0.255  1.0
  O  O28  1  0.057  0.045  0.249  1.0
  O  O29  1  0.943  0.955  0.751  1.0
  O  O30  1  0.557  0.955  0.251  1.0
  O  O31  1  0.659  0.833  0.966  1.0
[/CIF]
.
The compound described by Li2MgSiO4 is beta beryllia-derived structured and crystallizes in the monoclinic P2_1/c 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(3), and one O(4) atom to form LiO4 tetrahedra that share corners with two equivalent Li(2)O4 tetrahedra, corners with four equivalent Mg(1)O4 tetrahedra, corners with four equivalent Si(1)O4 tetrahedra, and  an edgeedge with one Li(2)O4 tetrahedra. In the second Li site, Li(2) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form LiO4 tetrahedra that share corners with two equivalent Li(1)O4 tetrahedra, corners with two equivalent Mg(1)O4 tetrahedra, corners with four equivalent Si(1)O4 tetrahedra,  an edgeedge with one Li(1)O4 tetrahedra, and  an edgeedge with one Mg(1)O4 tetrahedra. Mg(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form MgO4 tetrahedra that share corners with two equivalent Li(2)O4 tetrahedra, corners with four equivalent Li(1)O4 tetrahedra, corners with four equivalent Si(1)O4 tetrahedra, and  an edgeedge with one Li(2)O4 tetrahedra. Si(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SiO4 tetrahedra that share corners with four equivalent Li(1)O4 tetrahedra, corners with four equivalent Li(2)O4 tetrahedra, and corners with four equivalent Mg(1)O4 tetrahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Li(1), one Li(2), one Mg(1), and one Si(1) atom to form a mixture of corner and edge-sharing OLi2MgSi tetrahedra. In the second O site, O(2) is bonded to one Li(1), one Li(2), one Mg(1), and one Si(1) atom to form corner-sharing OLi2MgSi tetrahedra. In the third O site, O(3) is bonded to one Li(1), one Li(2), one Mg(1), and one Si(1) atom to form a mixture of corner and edge-sharing OLi2MgSi tetrahedra. In the fourth O site, O(4) is bonded to one Li(1), one Li(2), one Mg(1), and one Si(1) atom to form a mixture of distorted corner and edge-sharing OLi2MgSi trigonal pyramids. is represented by the CIF card [CIF]
data_Li2MgSiO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.802
_cell_length_b   5.071
_cell_length_c   8.102
_cell_angle_alpha   51.706
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   348.296
_cell_formula_units_Z   4
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  0.838  0.689  0.004  1.0
  Li  Li1  1  0.338  0.311  0.496  1.0
  Li  Li2  1  0.162  0.311  0.996  1.0
  Li  Li3  1  0.662  0.689  0.504  1.0
  Li  Li4  1  0.926  0.533  0.763  1.0
  Li  Li5  1  0.426  0.467  0.737  1.0
  Li  Li6  1  0.074  0.467  0.237  1.0
  Li  Li7  1  0.574  0.533  0.263  1.0
  Mg  Mg8  1  0.836  0.191  0.502  1.0
  Mg  Mg9  1  0.164  0.809  0.498  1.0
  Mg  Mg10  1  0.664  0.191  0.002  1.0
  Mg  Mg11  1  0.336  0.809  0.998  1.0
  Si  Si12  1  0.087  0.063  0.748  1.0
  Si  Si13  1  0.413  0.063  0.248  1.0
  Si  Si14  1  0.913  0.937  0.252  1.0
  Si  Si15  1  0.587  0.937  0.752  1.0
  O  O16  1  0.161  0.747  0.959  1.0
  O  O17  1  0.839  0.253  0.041  1.0
  O  O18  1  0.339  0.747  0.459  1.0
  O  O19  1  0.591  0.607  0.755  1.0
  O  O20  1  0.661  0.253  0.541  1.0
  O  O21  1  0.841  0.833  0.466  1.0
  O  O22  1  0.341  0.167  0.034  1.0
  O  O23  1  0.159  0.167  0.534  1.0
  O  O24  1  0.443  0.045  0.749  1.0
  O  O25  1  0.091  0.393  0.745  1.0
  O  O26  1  0.409  0.393  0.245  1.0
  O  O27  1  0.909  0.607  0.255  1.0
  O  O28  1  0.057  0.045  0.249  1.0
  O  O29  1  0.943  0.955  0.751  1.0
  O  O30  1  0.557  0.955  0.251  1.0
  O  O31  1  0.659  0.833  0.966  1.0
[/CIF]
.