The structure described by Li2Mg2Si4O11 crystallizes in the triclinic P-1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded in a 4-coordinate geometry to one O(1), one O(11), one O(3), and one O(8) atom. In the second Li site, Li(2) is bonded in a 5-coordinate geometry to one O(1), one O(10), one O(11), one O(2), and one O(9) atom. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(11), one O(4), one O(8), one O(9), and two equivalent O(5) atoms to form MgO6 octahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra,  an edgeedge with one Mg(1)O6 octahedra, and edges with three equivalent Mg(2)O6 octahedra. In the second Mg site, Mg(2) is bonded to one O(1), one O(5), one O(8), one O(9), and two equivalent O(4) atoms to form distorted MgO6 octahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra, and edges with three equivalent Mg(1)O6 octahedra. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(11), one O(2), and one O(3) atom to form SiO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one Mg(2)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 2-57°. In the second Si site, Si(2) is bonded to one O(2), one O(5), one O(6), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Mg(2)O6 octahedra, corners with two equivalent Mg(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and  a cornercorner with one Si(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 56-64°. In the third Si site, Si(3) is bonded to one O(10), one O(3), one O(4), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra, corners with two equivalent Mg(2)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 57-65°. In the fourth Si site, Si(4) is bonded to one O(10), one O(6), one O(8), and one O(9) atom to form SiO4 tetrahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Mg(2)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 51-65°. There are eleven inequivalent O sites. In the first O site, O(1) is bonded to one Li(1), one Li(2), one Mg(2), and one Si(1) atom to form distorted OLi2MgSi trigonal pyramids that share  a cornercorner with one O(5)Mg3Si tetrahedra,  an edgeedge with one O(8)LiMg2Si trigonal pyramid, and  an edgeedge with one O(9)LiMg2Si trigonal pyramid. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Li(2), one Si(1), and one Si(2) atom. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Li(1), one Si(1), and one Si(3) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Mg(1), two equivalent Mg(2), and one Si(3) atom. In the fifth O site, O(5) is bonded to one Mg(2), two equivalent Mg(1), and one Si(2) atom to form distorted OMg3Si tetrahedra that share  a cornercorner with one O(1)Li2MgSi trigonal pyramid,  a cornercorner with one O(9)LiMg2Si trigonal pyramid, corners with three equivalent O(8)LiMg2Si trigonal pyramids,  an edgeedge with one O(5)Mg3Si tetrahedra, and  an edgeedge with one O(9)LiMg2Si trigonal pyramid. In the sixth O site, O(6) is bonded in a distorted bent 120 degrees geometry to one Si(2) and one Si(4) atom. In the seventh O site, O(7) is bonded in a distorted bent 150 degrees geometry to one Si(2) and one Si(3) atom. In the eighth O site, O(8) is bonded to one Li(1), one Mg(1), one Mg(2), and one Si(4) atom to form distorted OLiMg2Si trigonal pyramids that share corners with three equivalent O(5)Mg3Si tetrahedra, corners with three equivalent O(9)LiMg2Si trigonal pyramids, and  an edgeedge with one O(1)Li2MgSi trigonal pyramid. In the ninth O site, O(9) is bonded to one Li(2), one Mg(1), one Mg(2), and one Si(4) atom to form OLiMg2Si trigonal pyramids that share  a cornercorner with one O(5)Mg3Si tetrahedra, corners with three equivalent O(8)LiMg2Si trigonal pyramids,  an edgeedge with one O(5)Mg3Si tetrahedra, and  an edgeedge with one O(1)Li2MgSi trigonal pyramid. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Li(2), one Si(3), and one Si(4) atom. In the eleventh O site, O(11) is bonded in a see-saw-like geometry to one Li(1), one Li(2), one Mg(1), and one Si(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Li2Mg2Si4O11
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.961
_cell_length_b   7.502
_cell_length_c   8.752
_cell_angle_alpha   99.462
_cell_angle_beta   101.055
_cell_angle_gamma   104.810
_symmetry_Int_Tables_number   1
_cell_volume   422.549
_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  0.610  0.794  0.196  1.0
  Li  Li1  1  0.142  0.754  0.152  1.0
  Li  Li2  1  0.390  0.206  0.804  1.0
  Li  Li3  1  0.858  0.246  0.848  1.0
  Mg  Mg4  1  0.118  0.380  0.611  1.0
  Mg  Mg5  1  0.369  0.620  0.399  1.0
  Mg  Mg6  1  0.631  0.380  0.601  1.0
  Mg  Mg7  1  0.882  0.620  0.389  1.0
  Si  Si8  1  0.760  0.608  0.968  1.0
  Si  Si9  1  0.960  0.226  0.233  1.0
  Si  Si10  1  0.521  0.224  0.226  1.0
  Si  Si11  1  0.233  0.025  0.405  1.0
  Si  Si12  1  0.240  0.392  0.032  1.0
  Si  Si13  1  0.767  0.975  0.595  1.0
  Si  Si14  1  0.479  0.776  0.774  1.0
  Si  Si15  1  0.040  0.774  0.767  1.0
  O  O16  1  0.324  0.594  0.159  1.0
  O  O17  1  0.975  0.740  0.933  1.0
  O  O18  1  0.399  0.260  0.058  1.0
  O  O19  1  0.414  0.590  0.630  1.0
  O  O20  1  0.063  0.416  0.374  1.0
  O  O21  1  0.676  0.406  0.841  1.0
  O  O22  1  0.980  0.952  0.706  1.0
  O  O23  1  0.290  0.849  0.818  1.0
  O  O24  1  0.020  0.048  0.294  1.0
  O  O25  1  0.675  0.805  0.436  1.0
  O  O26  1  0.183  0.805  0.416  1.0
  O  O27  1  0.025  0.260  0.067  1.0
  O  O28  1  0.710  0.151  0.182  1.0
  O  O29  1  0.381  0.039  0.274  1.0
  O  O30  1  0.601  0.740  0.942  1.0
  O  O31  1  0.817  0.195  0.584  1.0
  O  O32  1  0.619  0.961  0.726  1.0
  O  O33  1  0.937  0.584  0.626  1.0
  O  O34  1  0.183  0.382  0.844  1.0
  O  O35  1  0.325  0.195  0.564  1.0
  O  O36  1  0.817  0.618  0.156  1.0
  O  O37  1  0.586  0.410  0.370  1.0
[/CIF]
.
The structure described by Li2Mg2Si4O11 crystallizes in the triclinic P-1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded in a 4-coordinate geometry to one O(1), one O(11), one O(3), and one O(8) atom. In the second Li site, Li(2) is bonded in a 5-coordinate geometry to one O(1), one O(10), one O(11), one O(2), and one O(9) atom. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(11), one O(4), one O(8), one O(9), and two equivalent O(5) atoms to form MgO6 octahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra,  an edgeedge with one Mg(1)O6 octahedra, and edges with three equivalent Mg(2)O6 octahedra. In the second Mg site, Mg(2) is bonded to one O(1), one O(5), one O(8), one O(9), and two equivalent O(4) atoms to form distorted MgO6 octahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra, and edges with three equivalent Mg(1)O6 octahedra. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(11), one O(2), and one O(3) atom to form SiO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one Mg(2)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 2-57°. In the second Si site, Si(2) is bonded to one O(2), one O(5), one O(6), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Mg(2)O6 octahedra, corners with two equivalent Mg(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and  a cornercorner with one Si(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 56-64°. In the third Si site, Si(3) is bonded to one O(10), one O(3), one O(4), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra, corners with two equivalent Mg(2)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 57-65°. In the fourth Si site, Si(4) is bonded to one O(10), one O(6), one O(8), and one O(9) atom to form SiO4 tetrahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Mg(2)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 51-65°. There are eleven inequivalent O sites. In the first O site, O(1) is bonded to one Li(1), one Li(2), one Mg(2), and one Si(1) atom to form distorted OLi2MgSi trigonal pyramids that share  a cornercorner with one O(5)Mg3Si tetrahedra,  an edgeedge with one O(8)LiMg2Si trigonal pyramid, and  an edgeedge with one O(9)LiMg2Si trigonal pyramid. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Li(2), one Si(1), and one Si(2) atom. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Li(1), one Si(1), and one Si(3) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Mg(1), two equivalent Mg(2), and one Si(3) atom. In the fifth O site, O(5) is bonded to one Mg(2), two equivalent Mg(1), and one Si(2) atom to form distorted OMg3Si tetrahedra that share  a cornercorner with one O(1)Li2MgSi trigonal pyramid,  a cornercorner with one O(9)LiMg2Si trigonal pyramid, corners with three equivalent O(8)LiMg2Si trigonal pyramids,  an edgeedge with one O(5)Mg3Si tetrahedra, and  an edgeedge with one O(9)LiMg2Si trigonal pyramid. In the sixth O site, O(6) is bonded in a distorted bent 120 degrees geometry to one Si(2) and one Si(4) atom. In the seventh O site, O(7) is bonded in a distorted bent 150 degrees geometry to one Si(2) and one Si(3) atom. In the eighth O site, O(8) is bonded to one Li(1), one Mg(1), one Mg(2), and one Si(4) atom to form distorted OLiMg2Si trigonal pyramids that share corners with three equivalent O(5)Mg3Si tetrahedra, corners with three equivalent O(9)LiMg2Si trigonal pyramids, and  an edgeedge with one O(1)Li2MgSi trigonal pyramid. In the ninth O site, O(9) is bonded to one Li(2), one Mg(1), one Mg(2), and one Si(4) atom to form OLiMg2Si trigonal pyramids that share  a cornercorner with one O(5)Mg3Si tetrahedra, corners with three equivalent O(8)LiMg2Si trigonal pyramids,  an edgeedge with one O(5)Mg3Si tetrahedra, and  an edgeedge with one O(1)Li2MgSi trigonal pyramid. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Li(2), one Si(3), and one Si(4) atom. In the eleventh O site, O(11) is bonded in a see-saw-like geometry to one Li(1), one Li(2), one Mg(1), and one Si(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Li2Mg2Si4O11
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.961
_cell_length_b   7.502
_cell_length_c   8.752
_cell_angle_alpha   99.462
_cell_angle_beta   101.055
_cell_angle_gamma   104.810
_symmetry_Int_Tables_number   1
_cell_volume   422.549
_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  0.610  0.794  0.196  1.0
  Li  Li1  1  0.142  0.754  0.152  1.0
  Li  Li2  1  0.390  0.206  0.804  1.0
  Li  Li3  1  0.858  0.246  0.848  1.0
  Mg  Mg4  1  0.118  0.380  0.611  1.0
  Mg  Mg5  1  0.369  0.620  0.399  1.0
  Mg  Mg6  1  0.631  0.380  0.601  1.0
  Mg  Mg7  1  0.882  0.620  0.389  1.0
  Si  Si8  1  0.760  0.608  0.968  1.0
  Si  Si9  1  0.960  0.226  0.233  1.0
  Si  Si10  1  0.521  0.224  0.226  1.0
  Si  Si11  1  0.233  0.025  0.405  1.0
  Si  Si12  1  0.240  0.392  0.032  1.0
  Si  Si13  1  0.767  0.975  0.595  1.0
  Si  Si14  1  0.479  0.776  0.774  1.0
  Si  Si15  1  0.040  0.774  0.767  1.0
  O  O16  1  0.324  0.594  0.159  1.0
  O  O17  1  0.975  0.740  0.933  1.0
  O  O18  1  0.399  0.260  0.058  1.0
  O  O19  1  0.414  0.590  0.630  1.0
  O  O20  1  0.063  0.416  0.374  1.0
  O  O21  1  0.676  0.406  0.841  1.0
  O  O22  1  0.980  0.952  0.706  1.0
  O  O23  1  0.290  0.849  0.818  1.0
  O  O24  1  0.020  0.048  0.294  1.0
  O  O25  1  0.675  0.805  0.436  1.0
  O  O26  1  0.183  0.805  0.416  1.0
  O  O27  1  0.025  0.260  0.067  1.0
  O  O28  1  0.710  0.151  0.182  1.0
  O  O29  1  0.381  0.039  0.274  1.0
  O  O30  1  0.601  0.740  0.942  1.0
  O  O31  1  0.817  0.195  0.584  1.0
  O  O32  1  0.619  0.961  0.726  1.0
  O  O33  1  0.937  0.584  0.626  1.0
  O  O34  1  0.183  0.382  0.844  1.0
  O  O35  1  0.325  0.195  0.564  1.0
  O  O36  1  0.817  0.618  0.156  1.0
  O  O37  1  0.586  0.410  0.370  1.0
[/CIF]
.