The structure described by MgWP2O7 crystallizes in the monoclinic P2_1/c space group. Mg(1) is bonded to one O(2), one O(3), one O(5), one O(6), and one O(7) atom to form MgO5 trigonal bipyramids that share corners with two equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and edges with two equivalent W(1)O5 square pyramids. W(1) is bonded to one O(3), one O(4), one O(5), one O(6), and one O(7) atom to form distorted WO5 square pyramids that share corners with two equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and edges with two equivalent Mg(1)O5 trigonal bipyramids. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(4), and one O(7) atom to form PO4 tetrahedra that share corners with two equivalent W(1)O5 square pyramids,  a cornercorner with one P(2)O4 tetrahedra, and corners with two equivalent Mg(1)O5 trigonal bipyramids. In the second P site, P(2) is bonded to one O(1), one O(3), one O(5), and one O(6) atom to form PO4 tetrahedra that share corners with three equivalent W(1)O5 square pyramids,  a cornercorner with one P(1)O4 tetrahedra, and corners with three equivalent Mg(1)O5 trigonal bipyramids. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Mg(1) and one P(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Mg(1), one W(1), and one P(2) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one W(1) and one P(1) atom. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to one Mg(1), one W(1), and one P(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Mg(1), one W(1), and one P(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Mg(1), one W(1), and one P(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgP2WO7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.710
_cell_length_b   7.175
_cell_length_c   9.677
_cell_angle_alpha   74.281
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   582.156
_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
  Mg  Mg0  1  0.928  0.313  0.804  1.0
  Mg  Mg1  1  0.428  0.687  0.696  1.0
  Mg  Mg2  1  0.572  0.313  0.304  1.0
  Mg  Mg3  1  0.072  0.687  0.196  1.0
  P  P4  1  0.758  0.910  0.274  1.0
  P  P5  1  0.224  0.456  0.973  1.0
  P  P6  1  0.742  0.910  0.774  1.0
  P  P7  1  0.276  0.456  0.473  1.0
  P  P8  1  0.258  0.090  0.226  1.0
  P  P9  1  0.724  0.544  0.527  1.0
  P  P10  1  0.776  0.544  0.027  1.0
  P  P11  1  0.242  0.090  0.726  1.0
  W  W12  1  0.055  0.748  0.617  1.0
  W  W13  1  0.945  0.252  0.383  1.0
  W  W14  1  0.555  0.252  0.883  1.0
  W  W15  1  0.445  0.748  0.117  1.0
  O  O16  1  0.203  0.243  0.077  1.0
  O  O17  1  0.579  0.861  0.744  1.0
  O  O18  1  0.921  0.861  0.244  1.0
  O  O19  1  0.379  0.473  0.890  1.0
  O  O20  1  0.797  0.757  0.923  1.0
  O  O21  1  0.143  0.096  0.341  1.0
  O  O22  1  0.621  0.527  0.110  1.0
  O  O23  1  0.087  0.482  0.873  1.0
  O  O24  1  0.268  0.602  0.566  1.0
  O  O25  1  0.857  0.904  0.659  1.0
  O  O26  1  0.357  0.096  0.841  1.0
  O  O27  1  0.752  0.108  0.812  1.0
  O  O28  1  0.252  0.892  0.688  1.0
  O  O29  1  0.297  0.243  0.577  1.0
  O  O30  1  0.643  0.904  0.159  1.0
  O  O31  1  0.079  0.139  0.756  1.0
  O  O32  1  0.248  0.892  0.188  1.0
  O  O33  1  0.913  0.518  0.127  1.0
  O  O34  1  0.232  0.602  0.066  1.0
  O  O35  1  0.768  0.398  0.934  1.0
  O  O36  1  0.879  0.527  0.610  1.0
  O  O37  1  0.413  0.482  0.373  1.0
  O  O38  1  0.587  0.518  0.627  1.0
  O  O39  1  0.421  0.139  0.256  1.0
  O  O40  1  0.748  0.108  0.312  1.0
  O  O41  1  0.121  0.473  0.390  1.0
  O  O42  1  0.732  0.398  0.434  1.0
  O  O43  1  0.703  0.757  0.423  1.0
[/CIF]
.
The structure described by MgWP2O7 crystallizes in the monoclinic P2_1/c space group. Mg(1) is bonded to one O(2), one O(3), one O(5), one O(6), and one O(7) atom to form MgO5 trigonal bipyramids that share corners with two equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and edges with two equivalent W(1)O5 square pyramids. W(1) is bonded to one O(3), one O(4), one O(5), one O(6), and one O(7) atom to form distorted WO5 square pyramids that share corners with two equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and edges with two equivalent Mg(1)O5 trigonal bipyramids. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(4), and one O(7) atom to form PO4 tetrahedra that share corners with two equivalent W(1)O5 square pyramids,  a cornercorner with one P(2)O4 tetrahedra, and corners with two equivalent Mg(1)O5 trigonal bipyramids. In the second P site, P(2) is bonded to one O(1), one O(3), one O(5), and one O(6) atom to form PO4 tetrahedra that share corners with three equivalent W(1)O5 square pyramids,  a cornercorner with one P(1)O4 tetrahedra, and corners with three equivalent Mg(1)O5 trigonal bipyramids. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Mg(1) and one P(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Mg(1), one W(1), and one P(2) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one W(1) and one P(1) atom. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to one Mg(1), one W(1), and one P(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Mg(1), one W(1), and one P(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Mg(1), one W(1), and one P(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgP2WO7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.710
_cell_length_b   7.175
_cell_length_c   9.677
_cell_angle_alpha   74.281
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   582.156
_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
  Mg  Mg0  1  0.928  0.313  0.804  1.0
  Mg  Mg1  1  0.428  0.687  0.696  1.0
  Mg  Mg2  1  0.572  0.313  0.304  1.0
  Mg  Mg3  1  0.072  0.687  0.196  1.0
  P  P4  1  0.758  0.910  0.274  1.0
  P  P5  1  0.224  0.456  0.973  1.0
  P  P6  1  0.742  0.910  0.774  1.0
  P  P7  1  0.276  0.456  0.473  1.0
  P  P8  1  0.258  0.090  0.226  1.0
  P  P9  1  0.724  0.544  0.527  1.0
  P  P10  1  0.776  0.544  0.027  1.0
  P  P11  1  0.242  0.090  0.726  1.0
  W  W12  1  0.055  0.748  0.617  1.0
  W  W13  1  0.945  0.252  0.383  1.0
  W  W14  1  0.555  0.252  0.883  1.0
  W  W15  1  0.445  0.748  0.117  1.0
  O  O16  1  0.203  0.243  0.077  1.0
  O  O17  1  0.579  0.861  0.744  1.0
  O  O18  1  0.921  0.861  0.244  1.0
  O  O19  1  0.379  0.473  0.890  1.0
  O  O20  1  0.797  0.757  0.923  1.0
  O  O21  1  0.143  0.096  0.341  1.0
  O  O22  1  0.621  0.527  0.110  1.0
  O  O23  1  0.087  0.482  0.873  1.0
  O  O24  1  0.268  0.602  0.566  1.0
  O  O25  1  0.857  0.904  0.659  1.0
  O  O26  1  0.357  0.096  0.841  1.0
  O  O27  1  0.752  0.108  0.812  1.0
  O  O28  1  0.252  0.892  0.688  1.0
  O  O29  1  0.297  0.243  0.577  1.0
  O  O30  1  0.643  0.904  0.159  1.0
  O  O31  1  0.079  0.139  0.756  1.0
  O  O32  1  0.248  0.892  0.188  1.0
  O  O33  1  0.913  0.518  0.127  1.0
  O  O34  1  0.232  0.602  0.066  1.0
  O  O35  1  0.768  0.398  0.934  1.0
  O  O36  1  0.879  0.527  0.610  1.0
  O  O37  1  0.413  0.482  0.373  1.0
  O  O38  1  0.587  0.518  0.627  1.0
  O  O39  1  0.421  0.139  0.256  1.0
  O  O40  1  0.748  0.108  0.312  1.0
  O  O41  1  0.121  0.473  0.390  1.0
  O  O42  1  0.732  0.398  0.434  1.0
  O  O43  1  0.703  0.757  0.423  1.0
[/CIF]
.