The crystal structure described by Er2P4O13 crystallizes in the monoclinic C2/c space group. Er(1) is bonded in a 8-coordinate geometry to one O(2), one O(5), two equivalent O(1), two equivalent O(4), and two equivalent O(6) atoms. 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(7) atom to form corner-sharing PO4 tetrahedra. In the second P site, P(2) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form corner-sharing PO4 tetrahedra. There are seven inequivalent O sites. In the first O site, O(6) is bonded in a 3-coordinate geometry to two equivalent Er(1) and one P(2) atom. In the second O site, O(7) is bonded in a bent 120 degrees geometry to two equivalent P(1) atoms. In the third O site, O(1) is bonded in a distorted single-bond geometry to two equivalent Er(1) and one P(1) atom. In the fourth O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Er(1) and one P(1) atom. In the fifth O site, O(3) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom. In the sixth O site, O(4) is bonded in a 3-coordinate geometry to two equivalent Er(1) and one P(2) atom. In the seventh O site, O(5) is bonded in a bent 150 degrees geometry to one Er(1) and one P(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Er2P4O13
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.862
_cell_length_b   6.862
_cell_length_c   12.947
_cell_angle_alpha   76.013
_cell_angle_beta   76.013
_cell_angle_gamma   59.004
_symmetry_Int_Tables_number   1
_cell_volume   501.946
_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
  Er  Er0  1  0.692  0.696  0.449  1.0
  Er  Er1  1  0.696  0.692  0.949  1.0
  Er  Er2  1  0.304  0.308  0.051  1.0
  Er  Er3  1  0.308  0.304  0.551  1.0
  P  P4  1  0.839  0.138  0.367  1.0
  P  P5  1  0.760  0.773  0.160  1.0
  P  P6  1  0.862  0.161  0.133  1.0
  P  P7  1  0.227  0.240  0.340  1.0
  P  P8  1  0.773  0.760  0.660  1.0
  P  P9  1  0.138  0.839  0.867  1.0
  P  P10  1  0.240  0.227  0.840  1.0
  P  P11  1  0.161  0.862  0.633  1.0
  O  O12  1  0.673  0.317  0.441  1.0
  O  O13  1  0.877  0.897  0.397  1.0
  O  O14  1  0.899  0.907  0.153  1.0
  O  O15  1  0.897  0.877  0.897  1.0
  O  O16  1  0.925  0.574  0.095  1.0
  O  O17  1  0.907  0.899  0.653  1.0
  O  O18  1  0.693  0.705  0.277  1.0
  O  O19  1  0.426  0.075  0.405  1.0
  O  O20  1  0.317  0.673  0.941  1.0
  O  O21  1  0.562  0.926  0.093  1.0
  O  O22  1  0.295  0.307  0.223  1.0
  O  O23  1  0.926  0.562  0.593  1.0
  O  O24  1  0.754  0.246  0.250  1.0
  O  O25  1  0.074  0.438  0.407  1.0
  O  O26  1  0.705  0.693  0.777  1.0
  O  O27  1  0.438  0.074  0.907  1.0
  O  O28  1  0.683  0.327  0.059  1.0
  O  O29  1  0.574  0.925  0.595  1.0
  O  O30  1  0.307  0.295  0.723  1.0
  O  O31  1  0.093  0.101  0.347  1.0
  O  O32  1  0.075  0.426  0.905  1.0
  O  O33  1  0.103  0.123  0.103  1.0
  O  O34  1  0.101  0.093  0.847  1.0
  O  O35  1  0.246  0.754  0.750  1.0
  O  O36  1  0.123  0.103  0.603  1.0
  O  O37  1  0.327  0.683  0.559  1.0
[/CIF]
.
The crystal structure described by Er2P4O13 crystallizes in the monoclinic C2/c space group. Er(1) is bonded in a 8-coordinate geometry to one O(2), one O(5), two equivalent O(1), two equivalent O(4), and two equivalent O(6) atoms. 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(7) atom to form corner-sharing PO4 tetrahedra. In the second P site, P(2) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form corner-sharing PO4 tetrahedra. There are seven inequivalent O sites. In the first O site, O(6) is bonded in a 3-coordinate geometry to two equivalent Er(1) and one P(2) atom. In the second O site, O(7) is bonded in a bent 120 degrees geometry to two equivalent P(1) atoms. In the third O site, O(1) is bonded in a distorted single-bond geometry to two equivalent Er(1) and one P(1) atom. In the fourth O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Er(1) and one P(1) atom. In the fifth O site, O(3) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom. In the sixth O site, O(4) is bonded in a 3-coordinate geometry to two equivalent Er(1) and one P(2) atom. In the seventh O site, O(5) is bonded in a bent 150 degrees geometry to one Er(1) and one P(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Er2P4O13
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.862
_cell_length_b   6.862
_cell_length_c   12.947
_cell_angle_alpha   76.013
_cell_angle_beta   76.013
_cell_angle_gamma   59.004
_symmetry_Int_Tables_number   1
_cell_volume   501.946
_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
  Er  Er0  1  0.692  0.696  0.449  1.0
  Er  Er1  1  0.696  0.692  0.949  1.0
  Er  Er2  1  0.304  0.308  0.051  1.0
  Er  Er3  1  0.308  0.304  0.551  1.0
  P  P4  1  0.839  0.138  0.367  1.0
  P  P5  1  0.760  0.773  0.160  1.0
  P  P6  1  0.862  0.161  0.133  1.0
  P  P7  1  0.227  0.240  0.340  1.0
  P  P8  1  0.773  0.760  0.660  1.0
  P  P9  1  0.138  0.839  0.867  1.0
  P  P10  1  0.240  0.227  0.840  1.0
  P  P11  1  0.161  0.862  0.633  1.0
  O  O12  1  0.673  0.317  0.441  1.0
  O  O13  1  0.877  0.897  0.397  1.0
  O  O14  1  0.899  0.907  0.153  1.0
  O  O15  1  0.897  0.877  0.897  1.0
  O  O16  1  0.925  0.574  0.095  1.0
  O  O17  1  0.907  0.899  0.653  1.0
  O  O18  1  0.693  0.705  0.277  1.0
  O  O19  1  0.426  0.075  0.405  1.0
  O  O20  1  0.317  0.673  0.941  1.0
  O  O21  1  0.562  0.926  0.093  1.0
  O  O22  1  0.295  0.307  0.223  1.0
  O  O23  1  0.926  0.562  0.593  1.0
  O  O24  1  0.754  0.246  0.250  1.0
  O  O25  1  0.074  0.438  0.407  1.0
  O  O26  1  0.705  0.693  0.777  1.0
  O  O27  1  0.438  0.074  0.907  1.0
  O  O28  1  0.683  0.327  0.059  1.0
  O  O29  1  0.574  0.925  0.595  1.0
  O  O30  1  0.307  0.295  0.723  1.0
  O  O31  1  0.093  0.101  0.347  1.0
  O  O32  1  0.075  0.426  0.905  1.0
  O  O33  1  0.103  0.123  0.103  1.0
  O  O34  1  0.101  0.093  0.847  1.0
  O  O35  1  0.246  0.754  0.750  1.0
  O  O36  1  0.123  0.103  0.603  1.0
  O  O37  1  0.327  0.683  0.559  1.0
[/CIF]
.