The material structure described by Sr3MgTi2O7 crystallizes in the triclinic P1 space group. There are three inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 9-coordinate geometry to one O(7), two equivalent O(1), two equivalent O(6), and four equivalent O(2) atoms. In the second Sr site, Sr(2) is bonded in a 8-coordinate geometry to two equivalent O(4), two equivalent O(5), and four equivalent O(3) atoms. In the third Sr site, Sr(3) is bonded in a 9-coordinate geometry to one O(2), two equivalent O(4), two equivalent O(5), and four equivalent O(7) atoms. Mg(1) is bonded in a 5-coordinate geometry to one O(3), two equivalent O(1), and two equivalent O(6) atoms. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(3), one O(7), two equivalent O(4), and two equivalent O(5) atoms to form corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 1-2°. In the second Ti site, Ti(2) is bonded to one O(2), two equivalent O(1), and two equivalent O(6) atoms to form corner-sharing TiO5 square pyramids. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Sr(1), two equivalent Mg(1), and two equivalent Ti(2) atoms. In the second O site, O(2) is bonded to one Sr(3), four equivalent Sr(1), and one Ti(2) atom to form distorted OSr5Ti octahedra that share corners with two equivalent O(4)Sr4Ti2 octahedra, corners with two equivalent O(5)Sr4Ti2 octahedra, corners with four equivalent O(2)Sr5Ti octahedra, edges with four equivalent O(2)Sr5Ti octahedra, and edges with four equivalent O(7)Sr5Ti octahedra. The corner-sharing octahedral tilt angles range from 1-49°. In the third O site, O(3) is bonded to four equivalent Sr(2), one Mg(1), and one Ti(1) atom to form distorted OSr4MgTi octahedra that share  a cornercorner with one O(7)Sr5Ti octahedra, corners with four equivalent O(3)Sr4MgTi octahedra, corners with four equivalent O(4)Sr4Ti2 octahedra, corners with four equivalent O(5)Sr4Ti2 octahedra, edges with four equivalent O(3)Sr4MgTi octahedra, faces with two equivalent O(4)Sr4Ti2 octahedra, and faces with two equivalent O(5)Sr4Ti2 octahedra. The corner-sharing octahedral tilt angles range from 0-52°. In the fourth O site, O(4) is bonded to two equivalent Sr(2), two equivalent Sr(3), and two equivalent Ti(1) atoms to form distorted OSr4Ti2 octahedra that share corners with two equivalent O(4)Sr4Ti2 octahedra, corners with two equivalent O(2)Sr5Ti octahedra, corners with four equivalent O(3)Sr4MgTi octahedra, corners with four equivalent O(7)Sr5Ti octahedra, edges with two equivalent O(4)Sr4Ti2 octahedra, faces with two equivalent O(3)Sr4MgTi octahedra, faces with two equivalent O(7)Sr5Ti octahedra, and faces with four equivalent O(5)Sr4Ti2 octahedra. The corner-sharing octahedral tilt angles range from 2-55°. In the fifth O site, O(5) is bonded to two equivalent Sr(2), two equivalent Sr(3), and two equivalent Ti(1) atoms to form distorted OSr4Ti2 octahedra that share corners with two equivalent O(5)Sr4Ti2 octahedra, corners with two equivalent O(2)Sr5Ti octahedra, corners with four equivalent O(3)Sr4MgTi octahedra, corners with four equivalent O(7)Sr5Ti octahedra, edges with two equivalent O(5)Sr4Ti2 octahedra, faces with two equivalent O(3)Sr4MgTi octahedra, faces with two equivalent O(7)Sr5Ti octahedra, and faces with four equivalent O(4)Sr4Ti2 octahedra. The corner-sharing octahedral tilt angles range from 1-55°. In the sixth O site, O(6) is bonded in a distorted see-saw-like geometry to two equivalent Sr(1), two equivalent Mg(1), and two equivalent Ti(2) atoms. In the seventh O site, O(7) is bonded to one Sr(1), four equivalent Sr(3), and one Ti(1) atom to form distorted OSr5Ti octahedra that share  a cornercorner with one O(3)Sr4MgTi octahedra, corners with four equivalent O(4)Sr4Ti2 octahedra, corners with four equivalent O(5)Sr4Ti2 octahedra, corners with four equivalent O(7)Sr5Ti octahedra, edges with four equivalent O(2)Sr5Ti octahedra, edges with four equivalent O(7)Sr5Ti octahedra, faces with two equivalent O(4)Sr4Ti2 octahedra, and faces with two equivalent O(5)Sr4Ti2 octahedra. The corner-sharing octahedral tilt angles range from 0-55°. is represented by the CIF card [CIF]
data_Sr3MgTi2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.932
_cell_length_b   3.935
_cell_length_c   12.441
_cell_angle_alpha   108.097
_cell_angle_beta   90.362
_cell_angle_gamma   90.047
_symmetry_Int_Tables_number   1
_cell_volume   182.965
_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
  Sr  Sr0  1  0.204  0.387  0.592  1.0
  Sr  Sr1  1  0.709  0.361  0.070  1.0
  Sr  Sr2  1  0.715  0.657  0.370  1.0
  Mg  Mg3  1  0.195  0.674  0.870  1.0
  Ti  Ti4  1  0.212  0.007  0.219  1.0
  Ti  Ti5  1  0.695  0.064  0.760  1.0
  O  O6  1  0.696  0.581  0.786  1.0
  O  O7  1  0.735  0.860  0.590  1.0
  O  O8  1  0.208  0.829  0.035  1.0
  O  O9  1  0.712  0.006  0.217  1.0
  O  O10  1  0.212  0.506  0.217  1.0
  O  O11  1  0.206  0.092  0.788  1.0
  O  O12  1  0.217  0.177  0.393  1.0
[/CIF]
.
The material structure described by Sr3MgTi2O7 crystallizes in the triclinic P1 space group. There are three inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 9-coordinate geometry to one O(7), two equivalent O(1), two equivalent O(6), and four equivalent O(2) atoms. In the second Sr site, Sr(2) is bonded in a 8-coordinate geometry to two equivalent O(4), two equivalent O(5), and four equivalent O(3) atoms. In the third Sr site, Sr(3) is bonded in a 9-coordinate geometry to one O(2), two equivalent O(4), two equivalent O(5), and four equivalent O(7) atoms. Mg(1) is bonded in a 5-coordinate geometry to one O(3), two equivalent O(1), and two equivalent O(6) atoms. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(3), one O(7), two equivalent O(4), and two equivalent O(5) atoms to form corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 1-2°. In the second Ti site, Ti(2) is bonded to one O(2), two equivalent O(1), and two equivalent O(6) atoms to form corner-sharing TiO5 square pyramids. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Sr(1), two equivalent Mg(1), and two equivalent Ti(2) atoms. In the second O site, O(2) is bonded to one Sr(3), four equivalent Sr(1), and one Ti(2) atom to form distorted OSr5Ti octahedra that share corners with two equivalent O(4)Sr4Ti2 octahedra, corners with two equivalent O(5)Sr4Ti2 octahedra, corners with four equivalent O(2)Sr5Ti octahedra, edges with four equivalent O(2)Sr5Ti octahedra, and edges with four equivalent O(7)Sr5Ti octahedra. The corner-sharing octahedral tilt angles range from 1-49°. In the third O site, O(3) is bonded to four equivalent Sr(2), one Mg(1), and one Ti(1) atom to form distorted OSr4MgTi octahedra that share  a cornercorner with one O(7)Sr5Ti octahedra, corners with four equivalent O(3)Sr4MgTi octahedra, corners with four equivalent O(4)Sr4Ti2 octahedra, corners with four equivalent O(5)Sr4Ti2 octahedra, edges with four equivalent O(3)Sr4MgTi octahedra, faces with two equivalent O(4)Sr4Ti2 octahedra, and faces with two equivalent O(5)Sr4Ti2 octahedra. The corner-sharing octahedral tilt angles range from 0-52°. In the fourth O site, O(4) is bonded to two equivalent Sr(2), two equivalent Sr(3), and two equivalent Ti(1) atoms to form distorted OSr4Ti2 octahedra that share corners with two equivalent O(4)Sr4Ti2 octahedra, corners with two equivalent O(2)Sr5Ti octahedra, corners with four equivalent O(3)Sr4MgTi octahedra, corners with four equivalent O(7)Sr5Ti octahedra, edges with two equivalent O(4)Sr4Ti2 octahedra, faces with two equivalent O(3)Sr4MgTi octahedra, faces with two equivalent O(7)Sr5Ti octahedra, and faces with four equivalent O(5)Sr4Ti2 octahedra. The corner-sharing octahedral tilt angles range from 2-55°. In the fifth O site, O(5) is bonded to two equivalent Sr(2), two equivalent Sr(3), and two equivalent Ti(1) atoms to form distorted OSr4Ti2 octahedra that share corners with two equivalent O(5)Sr4Ti2 octahedra, corners with two equivalent O(2)Sr5Ti octahedra, corners with four equivalent O(3)Sr4MgTi octahedra, corners with four equivalent O(7)Sr5Ti octahedra, edges with two equivalent O(5)Sr4Ti2 octahedra, faces with two equivalent O(3)Sr4MgTi octahedra, faces with two equivalent O(7)Sr5Ti octahedra, and faces with four equivalent O(4)Sr4Ti2 octahedra. The corner-sharing octahedral tilt angles range from 1-55°. In the sixth O site, O(6) is bonded in a distorted see-saw-like geometry to two equivalent Sr(1), two equivalent Mg(1), and two equivalent Ti(2) atoms. In the seventh O site, O(7) is bonded to one Sr(1), four equivalent Sr(3), and one Ti(1) atom to form distorted OSr5Ti octahedra that share  a cornercorner with one O(3)Sr4MgTi octahedra, corners with four equivalent O(4)Sr4Ti2 octahedra, corners with four equivalent O(5)Sr4Ti2 octahedra, corners with four equivalent O(7)Sr5Ti octahedra, edges with four equivalent O(2)Sr5Ti octahedra, edges with four equivalent O(7)Sr5Ti octahedra, faces with two equivalent O(4)Sr4Ti2 octahedra, and faces with two equivalent O(5)Sr4Ti2 octahedra. The corner-sharing octahedral tilt angles range from 0-55°. is represented by the CIF card [CIF]
data_Sr3MgTi2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.932
_cell_length_b   3.935
_cell_length_c   12.441
_cell_angle_alpha   108.097
_cell_angle_beta   90.362
_cell_angle_gamma   90.047
_symmetry_Int_Tables_number   1
_cell_volume   182.965
_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
  Sr  Sr0  1  0.204  0.387  0.592  1.0
  Sr  Sr1  1  0.709  0.361  0.070  1.0
  Sr  Sr2  1  0.715  0.657  0.370  1.0
  Mg  Mg3  1  0.195  0.674  0.870  1.0
  Ti  Ti4  1  0.212  0.007  0.219  1.0
  Ti  Ti5  1  0.695  0.064  0.760  1.0
  O  O6  1  0.696  0.581  0.786  1.0
  O  O7  1  0.735  0.860  0.590  1.0
  O  O8  1  0.208  0.829  0.035  1.0
  O  O9  1  0.712  0.006  0.217  1.0
  O  O10  1  0.212  0.506  0.217  1.0
  O  O11  1  0.206  0.092  0.788  1.0
  O  O12  1  0.217  0.177  0.393  1.0
[/CIF]
.