The structure described by Ba3Er4O9 is Orthorhombic Perovskite-like structured and crystallizes in the trigonal R3 space group. There are three inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 6-coordinate geometry to three equivalent O(1) and three equivalent O(3) atoms. In the second Ba site, Ba(2) is bonded in a 6-coordinate geometry to three equivalent O(3) and six equivalent O(2) atoms. In the third Ba site, Ba(3) is bonded in a distorted trigonal planar geometry to three equivalent O(1), three equivalent O(2), and six equivalent O(3) atoms. There are four inequivalent Er sites. In the first Er site, Er(1) is bonded in a 6-coordinate geometry to three equivalent O(1) and three equivalent O(2) atoms. In the second Er site, Er(2) is bonded to three equivalent O(2) and three equivalent O(3) atoms to form corner-sharing ErO6 octahedra. The corner-sharing octahedral tilt angles are 16°. In the third Er site, Er(3) is bonded in a 6-coordinate geometry to three equivalent O(1) and three equivalent O(2) atoms. In the fourth Er site, Er(4) is bonded to three equivalent O(1) and three equivalent O(3) atoms to form corner-sharing ErO6 octahedra. The corner-sharing octahedral tilt angles are 16°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Ba(1), one Ba(3), one Er(1), one Er(3), and one Er(4) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Ba(3), two equivalent Ba(2), one Er(1), one Er(2), and one Er(3) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Ba(1), one Ba(2), two equivalent Ba(3), one Er(2), and one Er(4) atom. is represented by the CIF file [CIF]
data_Ba3Er4O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.080
_cell_length_b   9.080
_cell_length_c   9.080
_cell_angle_alpha   38.921
_cell_angle_beta   38.921
_cell_angle_gamma   38.921
_symmetry_Int_Tables_number   1
_cell_volume   265.716
_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  0.001  0.001  0.001  1.0
  Ba  Ba1  1  0.165  0.165  0.165  1.0
  Ba  Ba2  1  0.579  0.579  0.579  1.0
  Er  Er3  1  0.426  0.426  0.426  1.0
  Er  Er4  1  0.865  0.865  0.865  1.0
  Er  Er5  1  0.740  0.740  0.740  1.0
  Er  Er6  1  0.301  0.301  0.301  1.0
  O  O7  1  0.468  0.573  0.041  1.0
  O  O8  1  0.573  0.041  0.468  1.0
  O  O9  1  0.041  0.468  0.573  1.0
  O  O10  1  0.602  0.689  0.128  1.0
  O  O11  1  0.689  0.128  0.602  1.0
  O  O12  1  0.128  0.602  0.689  1.0
  O  O13  1  0.032  0.582  0.135  1.0
  O  O14  1  0.135  0.032  0.582  1.0
  O  O15  1  0.582  0.135  0.032  1.0
[/CIF]
.
The structure described by Ba3Er4O9 is Orthorhombic Perovskite-like structured and crystallizes in the trigonal R3 space group. There are three inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 6-coordinate geometry to three equivalent O(1) and three equivalent O(3) atoms. In the second Ba site, Ba(2) is bonded in a 6-coordinate geometry to three equivalent O(3) and six equivalent O(2) atoms. In the third Ba site, Ba(3) is bonded in a distorted trigonal planar geometry to three equivalent O(1), three equivalent O(2), and six equivalent O(3) atoms. There are four inequivalent Er sites. In the first Er site, Er(1) is bonded in a 6-coordinate geometry to three equivalent O(1) and three equivalent O(2) atoms. In the second Er site, Er(2) is bonded to three equivalent O(2) and three equivalent O(3) atoms to form corner-sharing ErO6 octahedra. The corner-sharing octahedral tilt angles are 16°. In the third Er site, Er(3) is bonded in a 6-coordinate geometry to three equivalent O(1) and three equivalent O(2) atoms. In the fourth Er site, Er(4) is bonded to three equivalent O(1) and three equivalent O(3) atoms to form corner-sharing ErO6 octahedra. The corner-sharing octahedral tilt angles are 16°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Ba(1), one Ba(3), one Er(1), one Er(3), and one Er(4) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Ba(3), two equivalent Ba(2), one Er(1), one Er(2), and one Er(3) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Ba(1), one Ba(2), two equivalent Ba(3), one Er(2), and one Er(4) atom. is represented by the CIF file [CIF]
data_Ba3Er4O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.080
_cell_length_b   9.080
_cell_length_c   9.080
_cell_angle_alpha   38.921
_cell_angle_beta   38.921
_cell_angle_gamma   38.921
_symmetry_Int_Tables_number   1
_cell_volume   265.716
_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  0.001  0.001  0.001  1.0
  Ba  Ba1  1  0.165  0.165  0.165  1.0
  Ba  Ba2  1  0.579  0.579  0.579  1.0
  Er  Er3  1  0.426  0.426  0.426  1.0
  Er  Er4  1  0.865  0.865  0.865  1.0
  Er  Er5  1  0.740  0.740  0.740  1.0
  Er  Er6  1  0.301  0.301  0.301  1.0
  O  O7  1  0.468  0.573  0.041  1.0
  O  O8  1  0.573  0.041  0.468  1.0
  O  O9  1  0.041  0.468  0.573  1.0
  O  O10  1  0.602  0.689  0.128  1.0
  O  O11  1  0.689  0.128  0.602  1.0
  O  O12  1  0.128  0.602  0.689  1.0
  O  O13  1  0.032  0.582  0.135  1.0
  O  O14  1  0.135  0.032  0.582  1.0
  O  O15  1  0.582  0.135  0.032  1.0
[/CIF]
.