The crystal structure described by Sr3MgSi2O8 crystallizes in the monoclinic C2/c space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 10-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(4), and four equivalent O(3) atoms. In the second Sr site, Sr(2) is bonded in a 9-coordinate geometry to one O(3), two equivalent O(4), three equivalent O(1), and three equivalent O(2) atoms. Mg(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form MgO6 octahedra that share corners with six equivalent Si(1)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 three equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-36°. There are four inequivalent O sites. In the first O site, O(4) is bonded in a 5-coordinate geometry to one Sr(1), two equivalent Sr(2), one Mg(1), and one Si(1) atom. In the second O site, O(1) is bonded in a 6-coordinate geometry to one Sr(1), three equivalent Sr(2), one Mg(1), and one Si(1) atom. In the third O site, O(2) is bonded in a 2-coordinate geometry to one Sr(1), three equivalent Sr(2), one Mg(1), and one Si(1) atom. In the fourth O site, O(3) is bonded in a 3-coordinate geometry to one Sr(2), two equivalent Sr(1), and one Si(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Sr3Mg(SiO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.526
_cell_length_b   5.526
_cell_length_c   14.035
_cell_angle_alpha   89.221
_cell_angle_beta   89.221
_cell_angle_gamma   59.826
_symmetry_Int_Tables_number   1
_cell_volume   370.464
_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
  Sr  Sr0  1  0.059  0.941  0.250  1.0
  Sr  Sr1  1  0.941  0.059  0.750  1.0
  Sr  Sr2  1  0.316  0.343  0.588  1.0
  Sr  Sr3  1  0.657  0.684  0.912  1.0
  Sr  Sr4  1  0.684  0.657  0.412  1.0
  Sr  Sr5  1  0.343  0.316  0.088  1.0
  Mg  Mg6  1  0.000  0.000  0.500  1.0
  Mg  Mg7  1  0.000  0.000  0.000  1.0
  Si  Si8  1  0.355  0.327  0.365  1.0
  Si  Si9  1  0.673  0.645  0.135  1.0
  Si  Si10  1  0.645  0.673  0.635  1.0
  Si  Si11  1  0.327  0.355  0.865  1.0
  O  O12  1  0.220  0.630  0.424  1.0
  O  O13  1  0.370  0.780  0.076  1.0
  O  O14  1  0.847  0.784  0.082  1.0
  O  O15  1  0.216  0.153  0.418  1.0
  O  O16  1  0.262  0.401  0.255  1.0
  O  O17  1  0.599  0.738  0.245  1.0
  O  O18  1  0.784  0.847  0.582  1.0
  O  O19  1  0.153  0.216  0.918  1.0
  O  O20  1  0.738  0.599  0.745  1.0
  O  O21  1  0.401  0.262  0.755  1.0
  O  O22  1  0.313  0.846  0.613  1.0
  O  O23  1  0.154  0.687  0.887  1.0
  O  O24  1  0.780  0.370  0.576  1.0
  O  O25  1  0.630  0.220  0.924  1.0
  O  O26  1  0.687  0.154  0.387  1.0
  O  O27  1  0.846  0.313  0.113  1.0
[/CIF]
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The crystal structure described by Sr3MgSi2O8 crystallizes in the monoclinic C2/c space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 10-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(4), and four equivalent O(3) atoms. In the second Sr site, Sr(2) is bonded in a 9-coordinate geometry to one O(3), two equivalent O(4), three equivalent O(1), and three equivalent O(2) atoms. Mg(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form MgO6 octahedra that share corners with six equivalent Si(1)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 three equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-36°. There are four inequivalent O sites. In the first O site, O(4) is bonded in a 5-coordinate geometry to one Sr(1), two equivalent Sr(2), one Mg(1), and one Si(1) atom. In the second O site, O(1) is bonded in a 6-coordinate geometry to one Sr(1), three equivalent Sr(2), one Mg(1), and one Si(1) atom. In the third O site, O(2) is bonded in a 2-coordinate geometry to one Sr(1), three equivalent Sr(2), one Mg(1), and one Si(1) atom. In the fourth O site, O(3) is bonded in a 3-coordinate geometry to one Sr(2), two equivalent Sr(1), and one Si(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Sr3Mg(SiO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.526
_cell_length_b   5.526
_cell_length_c   14.035
_cell_angle_alpha   89.221
_cell_angle_beta   89.221
_cell_angle_gamma   59.826
_symmetry_Int_Tables_number   1
_cell_volume   370.464
_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
  Sr  Sr0  1  0.059  0.941  0.250  1.0
  Sr  Sr1  1  0.941  0.059  0.750  1.0
  Sr  Sr2  1  0.316  0.343  0.588  1.0
  Sr  Sr3  1  0.657  0.684  0.912  1.0
  Sr  Sr4  1  0.684  0.657  0.412  1.0
  Sr  Sr5  1  0.343  0.316  0.088  1.0
  Mg  Mg6  1  0.000  0.000  0.500  1.0
  Mg  Mg7  1  0.000  0.000  0.000  1.0
  Si  Si8  1  0.355  0.327  0.365  1.0
  Si  Si9  1  0.673  0.645  0.135  1.0
  Si  Si10  1  0.645  0.673  0.635  1.0
  Si  Si11  1  0.327  0.355  0.865  1.0
  O  O12  1  0.220  0.630  0.424  1.0
  O  O13  1  0.370  0.780  0.076  1.0
  O  O14  1  0.847  0.784  0.082  1.0
  O  O15  1  0.216  0.153  0.418  1.0
  O  O16  1  0.262  0.401  0.255  1.0
  O  O17  1  0.599  0.738  0.245  1.0
  O  O18  1  0.784  0.847  0.582  1.0
  O  O19  1  0.153  0.216  0.918  1.0
  O  O20  1  0.738  0.599  0.745  1.0
  O  O21  1  0.401  0.262  0.755  1.0
  O  O22  1  0.313  0.846  0.613  1.0
  O  O23  1  0.154  0.687  0.887  1.0
  O  O24  1  0.780  0.370  0.576  1.0
  O  O25  1  0.630  0.220  0.924  1.0
  O  O26  1  0.687  0.154  0.387  1.0
  O  O27  1  0.846  0.313  0.113  1.0
[/CIF]
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