The crystal structure described by ErFeGe2O7 crystallizes in the monoclinic C2/m space group. Er(1) is bonded in a 6-coordinate geometry to two equivalent O(2), two equivalent O(4), and two equivalent O(5) atoms. Fe(1) is bonded to two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms to form distorted FeO6 octahedra that share corners with four equivalent Ge(2)O4 tetrahedra and  an edgeedge with one Fe(1)O6 octahedra. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), and two equivalent O(4) atoms. In the second Ge site, Ge(2) is bonded to one O(1), one O(3), and two equivalent O(5) atoms to form GeO4 tetrahedra that share corners with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-54°. There are five inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Ge(1) and one Ge(2) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to two equivalent Er(1) and one Ge(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to two equivalent Fe(1), one Ge(1), and one Ge(2) atom. In the fourth O site, O(4) is bonded in a trigonal non-coplanar geometry to one Er(1), one Fe(1), and one Ge(1) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Er(1), one Fe(1), and one Ge(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_ErFeGe2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.941
_cell_length_b   6.941
_cell_length_c   6.684
_cell_angle_alpha   70.046
_cell_angle_beta   70.046
_cell_angle_gamma   77.952
_symmetry_Int_Tables_number   1
_cell_volume   282.961
_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  0.202  0.798  0.000  1.0
  Er  Er1  1  0.798  0.202  0.000  1.0
  Fe  Fe2  1  0.693  0.307  0.500  1.0
  Fe  Fe3  1  0.307  0.693  0.500  1.0
  Ge  Ge4  1  0.302  0.302  0.928  1.0
  Ge  Ge5  1  0.698  0.698  0.072  1.0
  Ge  Ge6  1  0.787  0.787  0.508  1.0
  Ge  Ge7  1  0.213  0.213  0.492  1.0
  O  O8  1  0.698  0.698  0.802  1.0
  O  O9  1  0.302  0.302  0.198  1.0
  O  O10  1  0.867  0.867  0.043  1.0
  O  O11  1  0.133  0.133  0.957  1.0
  O  O12  1  0.365  0.365  0.541  1.0
  O  O13  1  0.635  0.635  0.459  1.0
  O  O14  1  0.568  0.220  0.833  1.0
  O  O15  1  0.432  0.780  0.167  1.0
  O  O16  1  0.780  0.432  0.167  1.0
  O  O17  1  0.220  0.568  0.833  1.0
  O  O18  1  0.057  0.728  0.396  1.0
  O  O19  1  0.943  0.272  0.604  1.0
  O  O20  1  0.272  0.943  0.604  1.0
  O  O21  1  0.728  0.057  0.396  1.0
[/CIF]
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The crystal structure described by ErFeGe2O7 crystallizes in the monoclinic C2/m space group. Er(1) is bonded in a 6-coordinate geometry to two equivalent O(2), two equivalent O(4), and two equivalent O(5) atoms. Fe(1) is bonded to two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms to form distorted FeO6 octahedra that share corners with four equivalent Ge(2)O4 tetrahedra and  an edgeedge with one Fe(1)O6 octahedra. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), and two equivalent O(4) atoms. In the second Ge site, Ge(2) is bonded to one O(1), one O(3), and two equivalent O(5) atoms to form GeO4 tetrahedra that share corners with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-54°. There are five inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Ge(1) and one Ge(2) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to two equivalent Er(1) and one Ge(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to two equivalent Fe(1), one Ge(1), and one Ge(2) atom. In the fourth O site, O(4) is bonded in a trigonal non-coplanar geometry to one Er(1), one Fe(1), and one Ge(1) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Er(1), one Fe(1), and one Ge(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_ErFeGe2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.941
_cell_length_b   6.941
_cell_length_c   6.684
_cell_angle_alpha   70.046
_cell_angle_beta   70.046
_cell_angle_gamma   77.952
_symmetry_Int_Tables_number   1
_cell_volume   282.961
_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  0.202  0.798  0.000  1.0
  Er  Er1  1  0.798  0.202  0.000  1.0
  Fe  Fe2  1  0.693  0.307  0.500  1.0
  Fe  Fe3  1  0.307  0.693  0.500  1.0
  Ge  Ge4  1  0.302  0.302  0.928  1.0
  Ge  Ge5  1  0.698  0.698  0.072  1.0
  Ge  Ge6  1  0.787  0.787  0.508  1.0
  Ge  Ge7  1  0.213  0.213  0.492  1.0
  O  O8  1  0.698  0.698  0.802  1.0
  O  O9  1  0.302  0.302  0.198  1.0
  O  O10  1  0.867  0.867  0.043  1.0
  O  O11  1  0.133  0.133  0.957  1.0
  O  O12  1  0.365  0.365  0.541  1.0
  O  O13  1  0.635  0.635  0.459  1.0
  O  O14  1  0.568  0.220  0.833  1.0
  O  O15  1  0.432  0.780  0.167  1.0
  O  O16  1  0.780  0.432  0.167  1.0
  O  O17  1  0.220  0.568  0.833  1.0
  O  O18  1  0.057  0.728  0.396  1.0
  O  O19  1  0.943  0.272  0.604  1.0
  O  O20  1  0.272  0.943  0.604  1.0
  O  O21  1  0.728  0.057  0.396  1.0
[/CIF]
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