The crystal structure described by BaMgP2O7 crystallizes in the monoclinic P2_1/c space group. Ba(1) is bonded in a 10-coordinate geometry to one O(2), one O(3), two equivalent O(1), two equivalent O(4), two equivalent O(6), and two equivalent O(7) atoms. Mg(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form distorted MgO6 octahedra that share  a cornercorner with one P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, and  an edgeedge with one P(2)O4 tetrahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(4), one O(5), and one O(7) atom to form PO4 tetrahedra that share corners with three equivalent Mg(1)O6 octahedra and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 45-47°. 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  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, and  an edgeedge with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles are 20°. There are seven inequivalent O sites. In the first O site, O(5) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the second O site, O(6) is bonded in a 4-coordinate geometry to two equivalent Ba(1), one Mg(1), and one P(2) atom. In the third O site, O(7) is bonded in a 2-coordinate geometry to two equivalent Ba(1), one Mg(1), and one P(1) atom. In the fourth O site, O(1) is bonded in a distorted single-bond geometry to two equivalent Ba(1), one Mg(1), and one P(2) atom. In the fifth O site, O(2) is bonded in a 3-coordinate geometry to one Ba(1), one Mg(1), and one P(1) atom. In the sixth O site, O(3) is bonded in a 2-coordinate geometry to one Ba(1), one Mg(1), and one P(2) atom. In the seventh O site, O(4) is bonded in a 2-coordinate geometry to two equivalent Ba(1), one Mg(1), and one P(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_BaMgP2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.651
_cell_length_b   5.553
_cell_length_c   13.960
_cell_angle_alpha   68.027
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   621.920
_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
  Ba  Ba0  1  0.127  0.058  0.703  1.0
  Ba  Ba1  1  0.627  0.942  0.797  1.0
  Ba  Ba2  1  0.873  0.942  0.297  1.0
  Ba  Ba3  1  0.373  0.058  0.203  1.0
  Mg  Mg4  1  0.334  0.334  0.878  1.0
  Mg  Mg5  1  0.834  0.666  0.622  1.0
  Mg  Mg6  1  0.666  0.666  0.122  1.0
  Mg  Mg7  1  0.166  0.334  0.378  1.0
  P  P8  1  0.186  0.698  0.518  1.0
  P  P9  1  0.686  0.302  0.982  1.0
  P  P10  1  0.814  0.302  0.482  1.0
  P  P11  1  0.314  0.698  0.018  1.0
  P  P12  1  0.938  0.402  0.830  1.0
  P  P13  1  0.438  0.598  0.670  1.0
  P  P14  1  0.062  0.598  0.170  1.0
  P  P15  1  0.562  0.402  0.330  1.0
  O  O16  1  0.904  0.694  0.793  1.0
  O  O17  1  0.404  0.306  0.707  1.0
  O  O18  1  0.096  0.306  0.207  1.0
  O  O19  1  0.596  0.694  0.293  1.0
  O  O20  1  0.190  0.440  0.502  1.0
  O  O21  1  0.690  0.560  0.998  1.0
  O  O22  1  0.810  0.560  0.498  1.0
  O  O23  1  0.310  0.440  0.002  1.0
  O  O24  1  0.107  0.325  0.846  1.0
  O  O25  1  0.607  0.675  0.654  1.0
  O  O26  1  0.893  0.675  0.154  1.0
  O  O27  1  0.393  0.325  0.346  1.0
  O  O28  1  0.160  0.934  0.419  1.0
  O  O29  1  0.660  0.066  0.081  1.0
  O  O30  1  0.840  0.066  0.581  1.0
  O  O31  1  0.340  0.934  0.919  1.0
  O  O32  1  0.643  0.255  0.442  1.0
  O  O33  1  0.143  0.745  0.058  1.0
  O  O34  1  0.357  0.745  0.558  1.0
  O  O35  1  0.857  0.255  0.942  1.0
  O  O36  1  0.636  0.301  0.251  1.0
  O  O37  1  0.136  0.699  0.249  1.0
  O  O38  1  0.364  0.699  0.749  1.0
  O  O39  1  0.864  0.301  0.751  1.0
  O  O40  1  0.425  0.682  0.107  1.0
  O  O41  1  0.925  0.318  0.393  1.0
  O  O42  1  0.575  0.318  0.893  1.0
  O  O43  1  0.075  0.682  0.607  1.0
[/CIF]
.
The crystal structure described by BaMgP2O7 crystallizes in the monoclinic P2_1/c space group. Ba(1) is bonded in a 10-coordinate geometry to one O(2), one O(3), two equivalent O(1), two equivalent O(4), two equivalent O(6), and two equivalent O(7) atoms. Mg(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form distorted MgO6 octahedra that share  a cornercorner with one P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, and  an edgeedge with one P(2)O4 tetrahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(4), one O(5), and one O(7) atom to form PO4 tetrahedra that share corners with three equivalent Mg(1)O6 octahedra and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 45-47°. 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  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, and  an edgeedge with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles are 20°. There are seven inequivalent O sites. In the first O site, O(5) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the second O site, O(6) is bonded in a 4-coordinate geometry to two equivalent Ba(1), one Mg(1), and one P(2) atom. In the third O site, O(7) is bonded in a 2-coordinate geometry to two equivalent Ba(1), one Mg(1), and one P(1) atom. In the fourth O site, O(1) is bonded in a distorted single-bond geometry to two equivalent Ba(1), one Mg(1), and one P(2) atom. In the fifth O site, O(2) is bonded in a 3-coordinate geometry to one Ba(1), one Mg(1), and one P(1) atom. In the sixth O site, O(3) is bonded in a 2-coordinate geometry to one Ba(1), one Mg(1), and one P(2) atom. In the seventh O site, O(4) is bonded in a 2-coordinate geometry to two equivalent Ba(1), one Mg(1), and one P(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_BaMgP2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.651
_cell_length_b   5.553
_cell_length_c   13.960
_cell_angle_alpha   68.027
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   621.920
_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
  Ba  Ba0  1  0.127  0.058  0.703  1.0
  Ba  Ba1  1  0.627  0.942  0.797  1.0
  Ba  Ba2  1  0.873  0.942  0.297  1.0
  Ba  Ba3  1  0.373  0.058  0.203  1.0
  Mg  Mg4  1  0.334  0.334  0.878  1.0
  Mg  Mg5  1  0.834  0.666  0.622  1.0
  Mg  Mg6  1  0.666  0.666  0.122  1.0
  Mg  Mg7  1  0.166  0.334  0.378  1.0
  P  P8  1  0.186  0.698  0.518  1.0
  P  P9  1  0.686  0.302  0.982  1.0
  P  P10  1  0.814  0.302  0.482  1.0
  P  P11  1  0.314  0.698  0.018  1.0
  P  P12  1  0.938  0.402  0.830  1.0
  P  P13  1  0.438  0.598  0.670  1.0
  P  P14  1  0.062  0.598  0.170  1.0
  P  P15  1  0.562  0.402  0.330  1.0
  O  O16  1  0.904  0.694  0.793  1.0
  O  O17  1  0.404  0.306  0.707  1.0
  O  O18  1  0.096  0.306  0.207  1.0
  O  O19  1  0.596  0.694  0.293  1.0
  O  O20  1  0.190  0.440  0.502  1.0
  O  O21  1  0.690  0.560  0.998  1.0
  O  O22  1  0.810  0.560  0.498  1.0
  O  O23  1  0.310  0.440  0.002  1.0
  O  O24  1  0.107  0.325  0.846  1.0
  O  O25  1  0.607  0.675  0.654  1.0
  O  O26  1  0.893  0.675  0.154  1.0
  O  O27  1  0.393  0.325  0.346  1.0
  O  O28  1  0.160  0.934  0.419  1.0
  O  O29  1  0.660  0.066  0.081  1.0
  O  O30  1  0.840  0.066  0.581  1.0
  O  O31  1  0.340  0.934  0.919  1.0
  O  O32  1  0.643  0.255  0.442  1.0
  O  O33  1  0.143  0.745  0.058  1.0
  O  O34  1  0.357  0.745  0.558  1.0
  O  O35  1  0.857  0.255  0.942  1.0
  O  O36  1  0.636  0.301  0.251  1.0
  O  O37  1  0.136  0.699  0.249  1.0
  O  O38  1  0.364  0.699  0.749  1.0
  O  O39  1  0.864  0.301  0.751  1.0
  O  O40  1  0.425  0.682  0.107  1.0
  O  O41  1  0.925  0.318  0.393  1.0
  O  O42  1  0.575  0.318  0.893  1.0
  O  O43  1  0.075  0.682  0.607  1.0
[/CIF]
.