The compound described by Mg3Ti2(Si2O7)2 crystallizes in the monoclinic C2/c space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(4), and two equivalent O(7) atoms. In the second Mg site, Mg(2) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form distorted MgO4 tetrahedra that share corners with two equivalent Ti(2)O6 octahedra, corners with four equivalent Si(2)O4 tetrahedra, and  an edgeedge with one Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles are 59°. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form distorted TiO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, edges with two equivalent Ti(2)O6 octahedra, and  an edgeedge with one Mg(2)O4 tetrahedra. In the second Ti site, Ti(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form TiO6 octahedra that share corners with two equivalent Mg(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and edges with two equivalent Ti(1)O6 octahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Ti(1)O6 octahedra,  a cornercorner with one Ti(2)O6 octahedra, and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 46-50°. In the second Si site, Si(2) is bonded to one O(1), one O(3), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Ti(1)O6 octahedra,  a cornercorner with one Ti(2)O6 octahedra, corners with two equivalent Mg(2)O4 tetrahedra, and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 68-70°. There are seven inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Mg(2), one Ti(2), and one Si(2) atom to form corner-sharing OMg2TiSi tetrahedra. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Mg(1), one Ti(1), and one Ti(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Mg(2), one Ti(1), and one Si(2) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Mg(1), one Ti(1), one Ti(2), and one Si(1) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(2) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to two equivalent Mg(1) and one Si(1) atom. is represented by the CIF card [CIF]
data_Mg3Ti2(Si2O7)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.327
_cell_length_b   9.327
_cell_length_c   9.755
_cell_angle_alpha   59.461
_cell_angle_beta   59.461
_cell_angle_gamma   48.562
_symmetry_Int_Tables_number   1
_cell_volume   528.130
_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
  Mg  Mg0  1  0.085  0.274  0.091  1.0
  Mg  Mg1  1  0.726  0.915  0.409  1.0
  Mg  Mg2  1  0.274  0.085  0.591  1.0
  Mg  Mg3  1  0.388  0.612  0.750  1.0
  Mg  Mg4  1  0.915  0.726  0.909  1.0
  Mg  Mg5  1  0.612  0.388  0.250  1.0
  Ti  Ti6  1  0.807  0.193  0.750  1.0
  Ti  Ti7  1  0.193  0.807  0.250  1.0
  Ti  Ti8  1  0.000  0.000  0.000  1.0
  Ti  Ti9  1  0.000  0.000  0.500  1.0
  Si  Si10  1  0.531  0.098  0.714  1.0
  Si  Si11  1  0.098  0.531  0.214  1.0
  Si  Si12  1  0.519  0.239  0.106  1.0
  Si  Si13  1  0.239  0.519  0.606  1.0
  Si  Si14  1  0.902  0.469  0.786  1.0
  Si  Si15  1  0.481  0.761  0.894  1.0
  Si  Si16  1  0.761  0.481  0.394  1.0
  Si  Si17  1  0.469  0.902  0.286  1.0
  O  O18  1  0.849  0.300  0.322  1.0
  O  O19  1  0.949  0.887  0.421  1.0
  O  O20  1  0.463  0.630  0.085  1.0
  O  O21  1  0.887  0.949  0.921  1.0
  O  O22  1  0.257  0.950  0.307  1.0
  O  O23  1  0.069  0.499  0.617  1.0
  O  O24  1  0.630  0.463  0.585  1.0
  O  O25  1  0.050  0.743  0.193  1.0
  O  O26  1  0.931  0.501  0.383  1.0
  O  O27  1  0.644  0.680  0.253  1.0
  O  O28  1  0.051  0.113  0.579  1.0
  O  O29  1  0.743  0.050  0.693  1.0
  O  O30  1  0.501  0.931  0.883  1.0
  O  O31  1  0.300  0.849  0.822  1.0
  O  O32  1  0.680  0.644  0.753  1.0
  O  O33  1  0.950  0.257  0.807  1.0
  O  O34  1  0.908  0.495  0.935  1.0
  O  O35  1  0.356  0.320  0.747  1.0
  O  O36  1  0.505  0.092  0.565  1.0
  O  O37  1  0.320  0.356  0.247  1.0
  O  O38  1  0.499  0.069  0.117  1.0
  O  O39  1  0.113  0.051  0.079  1.0
  O  O40  1  0.495  0.908  0.435  1.0
  O  O41  1  0.537  0.370  0.915  1.0
  O  O42  1  0.092  0.505  0.065  1.0
  O  O43  1  0.370  0.537  0.415  1.0
  O  O44  1  0.700  0.151  0.178  1.0
  O  O45  1  0.151  0.700  0.678  1.0
[/CIF]
.
The compound described by Mg3Ti2(Si2O7)2 crystallizes in the monoclinic C2/c space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(4), and two equivalent O(7) atoms. In the second Mg site, Mg(2) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form distorted MgO4 tetrahedra that share corners with two equivalent Ti(2)O6 octahedra, corners with four equivalent Si(2)O4 tetrahedra, and  an edgeedge with one Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles are 59°. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form distorted TiO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, edges with two equivalent Ti(2)O6 octahedra, and  an edgeedge with one Mg(2)O4 tetrahedra. In the second Ti site, Ti(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form TiO6 octahedra that share corners with two equivalent Mg(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and edges with two equivalent Ti(1)O6 octahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Ti(1)O6 octahedra,  a cornercorner with one Ti(2)O6 octahedra, and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 46-50°. In the second Si site, Si(2) is bonded to one O(1), one O(3), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Ti(1)O6 octahedra,  a cornercorner with one Ti(2)O6 octahedra, corners with two equivalent Mg(2)O4 tetrahedra, and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 68-70°. There are seven inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Mg(2), one Ti(2), and one Si(2) atom to form corner-sharing OMg2TiSi tetrahedra. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Mg(1), one Ti(1), and one Ti(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Mg(2), one Ti(1), and one Si(2) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Mg(1), one Ti(1), one Ti(2), and one Si(1) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(2) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to two equivalent Mg(1) and one Si(1) atom. is represented by the CIF card [CIF]
data_Mg3Ti2(Si2O7)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.327
_cell_length_b   9.327
_cell_length_c   9.755
_cell_angle_alpha   59.461
_cell_angle_beta   59.461
_cell_angle_gamma   48.562
_symmetry_Int_Tables_number   1
_cell_volume   528.130
_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
  Mg  Mg0  1  0.085  0.274  0.091  1.0
  Mg  Mg1  1  0.726  0.915  0.409  1.0
  Mg  Mg2  1  0.274  0.085  0.591  1.0
  Mg  Mg3  1  0.388  0.612  0.750  1.0
  Mg  Mg4  1  0.915  0.726  0.909  1.0
  Mg  Mg5  1  0.612  0.388  0.250  1.0
  Ti  Ti6  1  0.807  0.193  0.750  1.0
  Ti  Ti7  1  0.193  0.807  0.250  1.0
  Ti  Ti8  1  0.000  0.000  0.000  1.0
  Ti  Ti9  1  0.000  0.000  0.500  1.0
  Si  Si10  1  0.531  0.098  0.714  1.0
  Si  Si11  1  0.098  0.531  0.214  1.0
  Si  Si12  1  0.519  0.239  0.106  1.0
  Si  Si13  1  0.239  0.519  0.606  1.0
  Si  Si14  1  0.902  0.469  0.786  1.0
  Si  Si15  1  0.481  0.761  0.894  1.0
  Si  Si16  1  0.761  0.481  0.394  1.0
  Si  Si17  1  0.469  0.902  0.286  1.0
  O  O18  1  0.849  0.300  0.322  1.0
  O  O19  1  0.949  0.887  0.421  1.0
  O  O20  1  0.463  0.630  0.085  1.0
  O  O21  1  0.887  0.949  0.921  1.0
  O  O22  1  0.257  0.950  0.307  1.0
  O  O23  1  0.069  0.499  0.617  1.0
  O  O24  1  0.630  0.463  0.585  1.0
  O  O25  1  0.050  0.743  0.193  1.0
  O  O26  1  0.931  0.501  0.383  1.0
  O  O27  1  0.644  0.680  0.253  1.0
  O  O28  1  0.051  0.113  0.579  1.0
  O  O29  1  0.743  0.050  0.693  1.0
  O  O30  1  0.501  0.931  0.883  1.0
  O  O31  1  0.300  0.849  0.822  1.0
  O  O32  1  0.680  0.644  0.753  1.0
  O  O33  1  0.950  0.257  0.807  1.0
  O  O34  1  0.908  0.495  0.935  1.0
  O  O35  1  0.356  0.320  0.747  1.0
  O  O36  1  0.505  0.092  0.565  1.0
  O  O37  1  0.320  0.356  0.247  1.0
  O  O38  1  0.499  0.069  0.117  1.0
  O  O39  1  0.113  0.051  0.079  1.0
  O  O40  1  0.495  0.908  0.435  1.0
  O  O41  1  0.537  0.370  0.915  1.0
  O  O42  1  0.092  0.505  0.065  1.0
  O  O43  1  0.370  0.537  0.415  1.0
  O  O44  1  0.700  0.151  0.178  1.0
  O  O45  1  0.151  0.700  0.678  1.0
[/CIF]
.