The material described by Mn2P2O9 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(3), one O(4), one O(6), one O(7), and two equivalent O(5) atoms to form MnO6 octahedra that share corners with two equivalent Mn(2)O6 octahedra, corners with three equivalent P(1)O4 tetrahedra, and  an edgeedge with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. In the second Mn site, Mn(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MnO6 octahedra that share corners with two equivalent Mn(1)O6 octahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, and edges with two equivalent Mn(2)O6 octahedra. The corner-sharing octahedral tilt angles are 51°. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(6), and two equivalent O(5) atoms to form PO4 tetrahedra that share corners with two equivalent Mn(2)O6 octahedra and corners with three equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 6-53°. In the second P site, P(2) is bonded to one O(4), one O(7), and two equivalent O(1) atoms to form PO4 tetrahedra that share corners with two equivalent Mn(2)O6 octahedra and  an edgeedge with one Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles are 49°. There are seven inequivalent O sites. In the first O site, O(4) is bonded in an L-shaped geometry to one Mn(1) and one P(2) atom. In the second O site, O(5) is bonded in a bent 150 degrees geometry to one Mn(1) and one P(1) atom. In the third O site, O(6) is bonded in a linear geometry to one Mn(1) and one P(1) atom. In the fourth O site, O(7) is bonded in an L-shaped geometry to one Mn(1) and one P(2) atom. In the fifth O site, O(1) is bonded in a bent 120 degrees geometry to one Mn(2) and one P(2) atom. In the sixth O site, O(2) is bonded in a trigonal planar geometry to two equivalent Mn(2) and one P(1) atom. In the seventh O site, O(3) is bonded in a trigonal planar geometry to one Mn(1) and two equivalent Mn(2) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mn2P2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.217
_cell_length_b   7.663
_cell_length_c   13.838
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   659.230
_cell_formula_units_Z   4
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
  Mn  Mn0  1  0.250  0.854  0.375  1.0
  Mn  Mn1  1  0.750  0.146  0.625  1.0
  Mn  Mn2  1  0.750  0.354  0.125  1.0
  Mn  Mn3  1  0.250  0.646  0.875  1.0
  Mn  Mn4  1  0.000  0.500  0.500  1.0
  Mn  Mn5  1  0.000  0.000  0.000  1.0
  Mn  Mn6  1  0.500  0.000  0.000  1.0
  Mn  Mn7  1  0.500  0.500  0.500  1.0
  P  P8  1  0.750  0.854  0.437  1.0
  P  P9  1  0.250  0.146  0.563  1.0
  P  P10  1  0.250  0.354  0.063  1.0
  P  P11  1  0.750  0.646  0.937  1.0
  P  P12  1  0.250  0.896  0.190  1.0
  P  P13  1  0.250  0.604  0.690  1.0
  P  P14  1  0.750  0.396  0.310  1.0
  P  P15  1  0.750  0.104  0.810  1.0
  O  O16  1  0.545  0.092  0.874  1.0
  O  O17  1  0.045  0.908  0.126  1.0
  O  O18  1  0.455  0.592  0.626  1.0
  O  O19  1  0.955  0.408  0.374  1.0
  O  O20  1  0.455  0.908  0.126  1.0
  O  O21  1  0.955  0.092  0.874  1.0
  O  O22  1  0.545  0.408  0.374  1.0
  O  O23  1  0.045  0.592  0.626  1.0
  O  O24  1  0.750  0.838  0.986  1.0
  O  O25  1  0.250  0.162  0.014  1.0
  O  O26  1  0.250  0.338  0.514  1.0
  O  O27  1  0.750  0.662  0.486  1.0
  O  O28  1  0.250  0.638  0.453  1.0
  O  O29  1  0.750  0.362  0.547  1.0
  O  O30  1  0.750  0.138  0.047  1.0
  O  O31  1  0.250  0.862  0.953  1.0
  O  O32  1  0.250  0.726  0.253  1.0
  O  O33  1  0.750  0.274  0.747  1.0
  O  O34  1  0.750  0.226  0.247  1.0
  O  O35  1  0.250  0.774  0.753  1.0
  O  O36  1  0.946  0.644  0.871  1.0
  O  O37  1  0.446  0.356  0.129  1.0
  O  O38  1  0.054  0.144  0.629  1.0
  O  O39  1  0.554  0.856  0.371  1.0
  O  O40  1  0.054  0.356  0.129  1.0
  O  O41  1  0.554  0.644  0.871  1.0
  O  O42  1  0.946  0.856  0.371  1.0
  O  O43  1  0.446  0.144  0.629  1.0
  O  O44  1  0.250  0.010  0.485  1.0
  O  O45  1  0.750  0.533  0.226  1.0
  O  O46  1  0.750  0.967  0.726  1.0
  O  O47  1  0.250  0.033  0.274  1.0
  O  O48  1  0.250  0.490  0.985  1.0
  O  O49  1  0.750  0.510  0.015  1.0
  O  O50  1  0.750  0.990  0.515  1.0
  O  O51  1  0.250  0.467  0.774  1.0
[/CIF]
.
The material described by Mn2P2O9 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(3), one O(4), one O(6), one O(7), and two equivalent O(5) atoms to form MnO6 octahedra that share corners with two equivalent Mn(2)O6 octahedra, corners with three equivalent P(1)O4 tetrahedra, and  an edgeedge with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. In the second Mn site, Mn(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MnO6 octahedra that share corners with two equivalent Mn(1)O6 octahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, and edges with two equivalent Mn(2)O6 octahedra. The corner-sharing octahedral tilt angles are 51°. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(6), and two equivalent O(5) atoms to form PO4 tetrahedra that share corners with two equivalent Mn(2)O6 octahedra and corners with three equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 6-53°. In the second P site, P(2) is bonded to one O(4), one O(7), and two equivalent O(1) atoms to form PO4 tetrahedra that share corners with two equivalent Mn(2)O6 octahedra and  an edgeedge with one Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles are 49°. There are seven inequivalent O sites. In the first O site, O(4) is bonded in an L-shaped geometry to one Mn(1) and one P(2) atom. In the second O site, O(5) is bonded in a bent 150 degrees geometry to one Mn(1) and one P(1) atom. In the third O site, O(6) is bonded in a linear geometry to one Mn(1) and one P(1) atom. In the fourth O site, O(7) is bonded in an L-shaped geometry to one Mn(1) and one P(2) atom. In the fifth O site, O(1) is bonded in a bent 120 degrees geometry to one Mn(2) and one P(2) atom. In the sixth O site, O(2) is bonded in a trigonal planar geometry to two equivalent Mn(2) and one P(1) atom. In the seventh O site, O(3) is bonded in a trigonal planar geometry to one Mn(1) and two equivalent Mn(2) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mn2P2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.217
_cell_length_b   7.663
_cell_length_c   13.838
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   659.230
_cell_formula_units_Z   4
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
  Mn  Mn0  1  0.250  0.854  0.375  1.0
  Mn  Mn1  1  0.750  0.146  0.625  1.0
  Mn  Mn2  1  0.750  0.354  0.125  1.0
  Mn  Mn3  1  0.250  0.646  0.875  1.0
  Mn  Mn4  1  0.000  0.500  0.500  1.0
  Mn  Mn5  1  0.000  0.000  0.000  1.0
  Mn  Mn6  1  0.500  0.000  0.000  1.0
  Mn  Mn7  1  0.500  0.500  0.500  1.0
  P  P8  1  0.750  0.854  0.437  1.0
  P  P9  1  0.250  0.146  0.563  1.0
  P  P10  1  0.250  0.354  0.063  1.0
  P  P11  1  0.750  0.646  0.937  1.0
  P  P12  1  0.250  0.896  0.190  1.0
  P  P13  1  0.250  0.604  0.690  1.0
  P  P14  1  0.750  0.396  0.310  1.0
  P  P15  1  0.750  0.104  0.810  1.0
  O  O16  1  0.545  0.092  0.874  1.0
  O  O17  1  0.045  0.908  0.126  1.0
  O  O18  1  0.455  0.592  0.626  1.0
  O  O19  1  0.955  0.408  0.374  1.0
  O  O20  1  0.455  0.908  0.126  1.0
  O  O21  1  0.955  0.092  0.874  1.0
  O  O22  1  0.545  0.408  0.374  1.0
  O  O23  1  0.045  0.592  0.626  1.0
  O  O24  1  0.750  0.838  0.986  1.0
  O  O25  1  0.250  0.162  0.014  1.0
  O  O26  1  0.250  0.338  0.514  1.0
  O  O27  1  0.750  0.662  0.486  1.0
  O  O28  1  0.250  0.638  0.453  1.0
  O  O29  1  0.750  0.362  0.547  1.0
  O  O30  1  0.750  0.138  0.047  1.0
  O  O31  1  0.250  0.862  0.953  1.0
  O  O32  1  0.250  0.726  0.253  1.0
  O  O33  1  0.750  0.274  0.747  1.0
  O  O34  1  0.750  0.226  0.247  1.0
  O  O35  1  0.250  0.774  0.753  1.0
  O  O36  1  0.946  0.644  0.871  1.0
  O  O37  1  0.446  0.356  0.129  1.0
  O  O38  1  0.054  0.144  0.629  1.0
  O  O39  1  0.554  0.856  0.371  1.0
  O  O40  1  0.054  0.356  0.129  1.0
  O  O41  1  0.554  0.644  0.871  1.0
  O  O42  1  0.946  0.856  0.371  1.0
  O  O43  1  0.446  0.144  0.629  1.0
  O  O44  1  0.250  0.010  0.485  1.0
  O  O45  1  0.750  0.533  0.226  1.0
  O  O46  1  0.750  0.967  0.726  1.0
  O  O47  1  0.250  0.033  0.274  1.0
  O  O48  1  0.250  0.490  0.985  1.0
  O  O49  1  0.750  0.510  0.015  1.0
  O  O50  1  0.750  0.990  0.515  1.0
  O  O51  1  0.250  0.467  0.774  1.0
[/CIF]
.