The compound described by BaFe2(P2O7)2 crystallizes in the triclinic P-1 space group. Ba(1) is bonded in a 10-coordinate geometry to two equivalent O(2), two equivalent O(3), two equivalent O(5), two equivalent O(6), and two equivalent O(7) atoms. Fe(1) is bonded to one O(1), one O(2), one O(3), one O(5), one O(6), and one O(7) atom to form FeO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra and corners with three equivalent P(2)O4 tetrahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PO4 tetrahedra that share corners with three equivalent Fe(1)O6 octahedra and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 31-52°. In the second P site, P(2) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with three equivalent Fe(1)O6 octahedra and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 42-50°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Fe(1) and one P(1) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Ba(1), one Fe(1), and one P(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Ba(1), one Fe(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the fifth O site, O(5) is bonded in a distorted bent 150 degrees geometry to one Ba(1), one Fe(1), and one P(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Ba(1), one Fe(1), and one P(2) atom. In the seventh O site, O(7) is bonded in a 2-coordinate geometry to one Ba(1), one Fe(1), and one P(2) atom. is represented by the CIF card [CIF]
data_BaFe2(P2O7)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.161
_cell_length_b   6.243
_cell_length_c   7.865
_cell_angle_alpha   96.337
_cell_angle_beta   101.157
_cell_angle_gamma   105.600
_symmetry_Int_Tables_number   1
_cell_volume   281.607
_cell_formula_units_Z   1
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  0.000  0.000  0.000  1.0
  Fe  Fe1  1  0.376  0.695  0.228  1.0
  Fe  Fe2  1  0.624  0.305  0.772  1.0
  P  P3  1  0.520  0.753  0.664  1.0
  P  P4  1  0.480  0.247  0.336  1.0
  P  P5  1  0.816  0.533  0.192  1.0
  P  P6  1  0.184  0.467  0.808  1.0
  O  O7  1  0.531  0.768  0.478  1.0
  O  O8  1  0.469  0.232  0.522  1.0
  O  O9  1  0.567  0.979  0.781  1.0
  O  O10  1  0.433  0.021  0.219  1.0
  O  O11  1  0.686  0.637  0.757  1.0
  O  O12  1  0.314  0.363  0.243  1.0
  O  O13  1  0.262  0.603  0.659  1.0
  O  O14  1  0.738  0.397  0.341  1.0
  O  O15  1  0.063  0.677  0.266  1.0
  O  O16  1  0.937  0.323  0.734  1.0
  O  O17  1  0.213  0.644  0.966  1.0
  O  O18  1  0.787  0.356  0.034  1.0
  O  O19  1  0.667  0.688  0.154  1.0
  O  O20  1  0.333  0.312  0.846  1.0
[/CIF]
.
The compound described by BaFe2(P2O7)2 crystallizes in the triclinic P-1 space group. Ba(1) is bonded in a 10-coordinate geometry to two equivalent O(2), two equivalent O(3), two equivalent O(5), two equivalent O(6), and two equivalent O(7) atoms. Fe(1) is bonded to one O(1), one O(2), one O(3), one O(5), one O(6), and one O(7) atom to form FeO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra and corners with three equivalent P(2)O4 tetrahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PO4 tetrahedra that share corners with three equivalent Fe(1)O6 octahedra and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 31-52°. In the second P site, P(2) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with three equivalent Fe(1)O6 octahedra and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 42-50°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Fe(1) and one P(1) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Ba(1), one Fe(1), and one P(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Ba(1), one Fe(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the fifth O site, O(5) is bonded in a distorted bent 150 degrees geometry to one Ba(1), one Fe(1), and one P(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Ba(1), one Fe(1), and one P(2) atom. In the seventh O site, O(7) is bonded in a 2-coordinate geometry to one Ba(1), one Fe(1), and one P(2) atom. is represented by the CIF card [CIF]
data_BaFe2(P2O7)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.161
_cell_length_b   6.243
_cell_length_c   7.865
_cell_angle_alpha   96.337
_cell_angle_beta   101.157
_cell_angle_gamma   105.600
_symmetry_Int_Tables_number   1
_cell_volume   281.607
_cell_formula_units_Z   1
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  0.000  0.000  0.000  1.0
  Fe  Fe1  1  0.376  0.695  0.228  1.0
  Fe  Fe2  1  0.624  0.305  0.772  1.0
  P  P3  1  0.520  0.753  0.664  1.0
  P  P4  1  0.480  0.247  0.336  1.0
  P  P5  1  0.816  0.533  0.192  1.0
  P  P6  1  0.184  0.467  0.808  1.0
  O  O7  1  0.531  0.768  0.478  1.0
  O  O8  1  0.469  0.232  0.522  1.0
  O  O9  1  0.567  0.979  0.781  1.0
  O  O10  1  0.433  0.021  0.219  1.0
  O  O11  1  0.686  0.637  0.757  1.0
  O  O12  1  0.314  0.363  0.243  1.0
  O  O13  1  0.262  0.603  0.659  1.0
  O  O14  1  0.738  0.397  0.341  1.0
  O  O15  1  0.063  0.677  0.266  1.0
  O  O16  1  0.937  0.323  0.734  1.0
  O  O17  1  0.213  0.644  0.966  1.0
  O  O18  1  0.787  0.356  0.034  1.0
  O  O19  1  0.667  0.688  0.154  1.0
  O  O20  1  0.333  0.312  0.846  1.0
[/CIF]
.