The structure described by MgSiO2(OH)2 crystallizes in the monoclinic P2/m space group. Mg(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form MgO6 octahedra that share corners with eight equivalent Si(1)O6 octahedra and edges with two equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 52-55°. Si(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form SiO6 octahedra that share corners with eight equivalent Mg(1)O6 octahedra and edges with two equivalent Si(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 52-55°. There are two inequivalent H sites. In the first H site, H(1) is bonded in a linear geometry to two equivalent O(1) atoms. In the second H site, H(2) is bonded in a linear geometry to two equivalent O(2) atoms. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Mg(1), one Si(1), and one H(1) atom to form a mixture of distorted corner and edge-sharing OMg2SiH tetrahedra. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Mg(1), two equivalent Si(1), and one H(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgSi(HO2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.856
_cell_length_b   4.283
_cell_length_c   4.778
_cell_angle_alpha   86.836
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   58.355
_cell_formula_units_Z   1
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
  Mg  Mg0  1  0.500  0.500  0.500  1.0
  Si  Si1  1  0.000  0.000  0.000  1.0
  H  H2  1  0.000  0.000  0.500  1.0
  H  H3  1  0.500  0.500  0.000  1.0
  O  O4  1  0.000  0.796  0.330  1.0
  O  O5  1  0.000  0.204  0.670  1.0
  O  O6  1  0.500  0.756  0.882  1.0
  O  O7  1  0.500  0.244  0.118  1.0
[/CIF]
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The structure described by MgSiO2(OH)2 crystallizes in the monoclinic P2/m space group. Mg(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form MgO6 octahedra that share corners with eight equivalent Si(1)O6 octahedra and edges with two equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 52-55°. Si(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form SiO6 octahedra that share corners with eight equivalent Mg(1)O6 octahedra and edges with two equivalent Si(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 52-55°. There are two inequivalent H sites. In the first H site, H(1) is bonded in a linear geometry to two equivalent O(1) atoms. In the second H site, H(2) is bonded in a linear geometry to two equivalent O(2) atoms. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Mg(1), one Si(1), and one H(1) atom to form a mixture of distorted corner and edge-sharing OMg2SiH tetrahedra. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Mg(1), two equivalent Si(1), and one H(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgSi(HO2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.856
_cell_length_b   4.283
_cell_length_c   4.778
_cell_angle_alpha   86.836
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   58.355
_cell_formula_units_Z   1
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
  Mg  Mg0  1  0.500  0.500  0.500  1.0
  Si  Si1  1  0.000  0.000  0.000  1.0
  H  H2  1  0.000  0.000  0.500  1.0
  H  H3  1  0.500  0.500  0.000  1.0
  O  O4  1  0.000  0.796  0.330  1.0
  O  O5  1  0.000  0.204  0.670  1.0
  O  O6  1  0.500  0.756  0.882  1.0
  O  O7  1  0.500  0.244  0.118  1.0
[/CIF]
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