The crystal structure described by Mg3Mn2(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 to one O(1), one O(2), one O(4), and two equivalent O(7) atoms to form distorted MgO5 square pyramids that share  a cornercorner with one Mn(2)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, corners with three equivalent Si(1)O4 tetrahedra,  a cornercorner with one Mg(2)O4 trigonal pyramid,  an edgeedge with one Mn(2)O6 octahedra, and  an edgeedge with one Mg(1)O5 square pyramid. The corner-sharing octahedral tilt angles are 42°. In the second Mg site, Mg(2) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form distorted MgO4 trigonal pyramids that share corners with two equivalent Mn(2)O6 octahedra, corners with two equivalent Mg(1)O5 square pyramids, and corners with four equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 59°. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded in a 6-coordinate geometry to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. In the second Mn site, Mn(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form MnO6 octahedra that share corners with two equivalent Mg(1)O5 square pyramids, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, corners with two equivalent Mg(2)O4 trigonal pyramids, and edges with two equivalent Mg(1)O5 square pyramids. 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 Mn(2)O6 octahedra, corners with three equivalent Mg(1)O5 square pyramids, and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 49°. 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 Mn(2)O6 octahedra,  a cornercorner with one Mg(1)O5 square pyramid, corners with two equivalent Si(1)O4 tetrahedra, and corners with two equivalent Mg(2)O4 trigonal pyramids. The corner-sharing octahedral tilt angles are 73°. There are seven inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Mg(2), one Mn(2), and one Si(2) atom to form distorted corner-sharing OMg2MnSi tetrahedra. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Mg(1), one Mn(1), and one Mn(2) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Mg(2), one Mn(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 Mn(1), one Mn(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_Mg3Mn2(Si2O7)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.355
_cell_length_b   9.355
_cell_length_c   9.949
_cell_angle_alpha   58.953
_cell_angle_beta   58.953
_cell_angle_gamma   48.249
_symmetry_Int_Tables_number   1
_cell_volume   535.972
_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  0.074  0.263  0.111  1.0
  Mg  Mg1  1  0.737  0.926  0.389  1.0
  Mg  Mg2  1  0.263  0.074  0.611  1.0
  Mg  Mg3  1  0.391  0.609  0.750  1.0
  Mg  Mg4  1  0.926  0.737  0.889  1.0
  Mg  Mg5  1  0.609  0.391  0.250  1.0
  Mn  Mn6  1  0.787  0.213  0.750  1.0
  Mn  Mn7  1  0.213  0.787  0.250  1.0
  Mn  Mn8  1  0.000  0.000  0.000  1.0
  Mn  Mn9  1  0.000  0.000  0.500  1.0
  Si  Si10  1  0.548  0.080  0.705  1.0
  Si  Si11  1  0.080  0.548  0.205  1.0
  Si  Si12  1  0.513  0.249  0.106  1.0
  Si  Si13  1  0.249  0.513  0.606  1.0
  Si  Si14  1  0.920  0.452  0.795  1.0
  Si  Si15  1  0.487  0.751  0.894  1.0
  Si  Si16  1  0.751  0.487  0.394  1.0
  Si  Si17  1  0.452  0.920  0.295  1.0
  O  O18  1  0.829  0.317  0.319  1.0
  O  O19  1  0.968  0.888  0.413  1.0
  O  O20  1  0.457  0.634  0.087  1.0
  O  O21  1  0.888  0.968  0.913  1.0
  O  O22  1  0.231  0.992  0.307  1.0
  O  O23  1  0.073  0.500  0.624  1.0
  O  O24  1  0.634  0.457  0.587  1.0
  O  O25  1  0.008  0.769  0.193  1.0
  O  O26  1  0.927  0.500  0.376  1.0
  O  O27  1  0.615  0.694  0.270  1.0
  O  O28  1  0.032  0.112  0.587  1.0
  O  O29  1  0.769  0.008  0.693  1.0
  O  O30  1  0.500  0.927  0.876  1.0
  O  O31  1  0.317  0.829  0.819  1.0
  O  O32  1  0.694  0.615  0.770  1.0
  O  O33  1  0.992  0.231  0.807  1.0
  O  O34  1  0.919  0.481  0.941  1.0
  O  O35  1  0.385  0.306  0.730  1.0
  O  O36  1  0.519  0.081  0.559  1.0
  O  O37  1  0.306  0.385  0.230  1.0
  O  O38  1  0.500  0.073  0.124  1.0
  O  O39  1  0.112  0.032  0.087  1.0
  O  O40  1  0.481  0.919  0.441  1.0
  O  O41  1  0.543  0.366  0.913  1.0
  O  O42  1  0.081  0.519  0.059  1.0
  O  O43  1  0.366  0.543  0.413  1.0
  O  O44  1  0.683  0.171  0.181  1.0
  O  O45  1  0.171  0.683  0.681  1.0
[/CIF]
.
The crystal structure described by Mg3Mn2(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 to one O(1), one O(2), one O(4), and two equivalent O(7) atoms to form distorted MgO5 square pyramids that share  a cornercorner with one Mn(2)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, corners with three equivalent Si(1)O4 tetrahedra,  a cornercorner with one Mg(2)O4 trigonal pyramid,  an edgeedge with one Mn(2)O6 octahedra, and  an edgeedge with one Mg(1)O5 square pyramid. The corner-sharing octahedral tilt angles are 42°. In the second Mg site, Mg(2) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form distorted MgO4 trigonal pyramids that share corners with two equivalent Mn(2)O6 octahedra, corners with two equivalent Mg(1)O5 square pyramids, and corners with four equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 59°. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded in a 6-coordinate geometry to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. In the second Mn site, Mn(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form MnO6 octahedra that share corners with two equivalent Mg(1)O5 square pyramids, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, corners with two equivalent Mg(2)O4 trigonal pyramids, and edges with two equivalent Mg(1)O5 square pyramids. 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 Mn(2)O6 octahedra, corners with three equivalent Mg(1)O5 square pyramids, and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 49°. 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 Mn(2)O6 octahedra,  a cornercorner with one Mg(1)O5 square pyramid, corners with two equivalent Si(1)O4 tetrahedra, and corners with two equivalent Mg(2)O4 trigonal pyramids. The corner-sharing octahedral tilt angles are 73°. There are seven inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Mg(2), one Mn(2), and one Si(2) atom to form distorted corner-sharing OMg2MnSi tetrahedra. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Mg(1), one Mn(1), and one Mn(2) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Mg(2), one Mn(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 Mn(1), one Mn(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_Mg3Mn2(Si2O7)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.355
_cell_length_b   9.355
_cell_length_c   9.949
_cell_angle_alpha   58.953
_cell_angle_beta   58.953
_cell_angle_gamma   48.249
_symmetry_Int_Tables_number   1
_cell_volume   535.972
_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  0.074  0.263  0.111  1.0
  Mg  Mg1  1  0.737  0.926  0.389  1.0
  Mg  Mg2  1  0.263  0.074  0.611  1.0
  Mg  Mg3  1  0.391  0.609  0.750  1.0
  Mg  Mg4  1  0.926  0.737  0.889  1.0
  Mg  Mg5  1  0.609  0.391  0.250  1.0
  Mn  Mn6  1  0.787  0.213  0.750  1.0
  Mn  Mn7  1  0.213  0.787  0.250  1.0
  Mn  Mn8  1  0.000  0.000  0.000  1.0
  Mn  Mn9  1  0.000  0.000  0.500  1.0
  Si  Si10  1  0.548  0.080  0.705  1.0
  Si  Si11  1  0.080  0.548  0.205  1.0
  Si  Si12  1  0.513  0.249  0.106  1.0
  Si  Si13  1  0.249  0.513  0.606  1.0
  Si  Si14  1  0.920  0.452  0.795  1.0
  Si  Si15  1  0.487  0.751  0.894  1.0
  Si  Si16  1  0.751  0.487  0.394  1.0
  Si  Si17  1  0.452  0.920  0.295  1.0
  O  O18  1  0.829  0.317  0.319  1.0
  O  O19  1  0.968  0.888  0.413  1.0
  O  O20  1  0.457  0.634  0.087  1.0
  O  O21  1  0.888  0.968  0.913  1.0
  O  O22  1  0.231  0.992  0.307  1.0
  O  O23  1  0.073  0.500  0.624  1.0
  O  O24  1  0.634  0.457  0.587  1.0
  O  O25  1  0.008  0.769  0.193  1.0
  O  O26  1  0.927  0.500  0.376  1.0
  O  O27  1  0.615  0.694  0.270  1.0
  O  O28  1  0.032  0.112  0.587  1.0
  O  O29  1  0.769  0.008  0.693  1.0
  O  O30  1  0.500  0.927  0.876  1.0
  O  O31  1  0.317  0.829  0.819  1.0
  O  O32  1  0.694  0.615  0.770  1.0
  O  O33  1  0.992  0.231  0.807  1.0
  O  O34  1  0.919  0.481  0.941  1.0
  O  O35  1  0.385  0.306  0.730  1.0
  O  O36  1  0.519  0.081  0.559  1.0
  O  O37  1  0.306  0.385  0.230  1.0
  O  O38  1  0.500  0.073  0.124  1.0
  O  O39  1  0.112  0.032  0.087  1.0
  O  O40  1  0.481  0.919  0.441  1.0
  O  O41  1  0.543  0.366  0.913  1.0
  O  O42  1  0.081  0.519  0.059  1.0
  O  O43  1  0.366  0.543  0.413  1.0
  O  O44  1  0.683  0.171  0.181  1.0
  O  O45  1  0.171  0.683  0.681  1.0
[/CIF]
.