The compound described by Ba3Er2MoO9 crystallizes in the monoclinic C2/c space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to one O(5), two equivalent O(1), three equivalent O(2), three equivalent O(3), and three equivalent O(4) atoms to form distorted BaO12 cuboctahedra that share corners with three equivalent Ba(2)O12 cuboctahedra, corners with nine equivalent Ba(1)O12 cuboctahedra, faces with three equivalent Ba(1)O12 cuboctahedra, faces with three equivalent Ba(2)O12 cuboctahedra, faces with three equivalent Mo(1)O6 octahedra, and faces with five equivalent Er(1)O6 octahedra. In the second Ba site, Ba(2) is bonded to two equivalent O(2), two equivalent O(3), two equivalent O(4), two equivalent O(5), and four equivalent O(1) atoms to form BaO12 cuboctahedra that share corners with six equivalent Ba(1)O12 cuboctahedra, corners with six equivalent Ba(2)O12 cuboctahedra, faces with six equivalent Ba(1)O12 cuboctahedra, faces with two equivalent Mo(1)O6 octahedra, and faces with six equivalent Er(1)O6 octahedra. Er(1) is bonded to one O(2), one O(3), one O(4), one O(5), and two equivalent O(1) atoms to form ErO6 octahedra that share corners with three equivalent Er(1)O6 octahedra, corners with three equivalent Mo(1)O6 octahedra, faces with three equivalent Ba(2)O12 cuboctahedra, and faces with five equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-14°. Mo(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form MoO6 octahedra that share corners with six equivalent Er(1)O6 octahedra, faces with two equivalent Ba(2)O12 cuboctahedra, and faces with six equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 1-12°. There are five inequivalent O sites. In the first O site, O(4) is bonded in a distorted linear geometry to one Ba(2), three equivalent Ba(1), one Er(1), and one Mo(1) atom. In the second O site, O(5) is bonded in a distorted linear geometry to two equivalent Ba(1), two equivalent Ba(2), and two equivalent Er(1) atoms. In the third O site, O(1) is bonded in a 2-coordinate geometry to two equivalent Ba(1), two equivalent Ba(2), and two equivalent Er(1) atoms. In the fourth O site, O(2) is bonded in a 2-coordinate geometry to one Ba(2), three equivalent Ba(1), one Er(1), and one Mo(1) atom. In the fifth O site, O(3) is bonded in a 2-coordinate geometry to one Ba(2), three equivalent Ba(1), one Er(1), and one Mo(1) atom. is represented by the CIF file [CIF]
data_Ba3Er2MoO9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.065
_cell_length_b   6.065
_cell_length_c   14.843
_cell_angle_alpha   89.758
_cell_angle_beta   89.758
_cell_angle_gamma   59.833
_symmetry_Int_Tables_number   1
_cell_volume   472.012
_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
  Ba  Ba0  1  0.668  0.665  0.088  1.0
  Ba  Ba1  1  0.998  0.002  0.750  1.0
  Ba  Ba2  1  0.335  0.332  0.412  1.0
  Ba  Ba3  1  0.332  0.335  0.912  1.0
  Ba  Ba4  1  0.665  0.668  0.588  1.0
  Ba  Ba5  1  0.002  0.998  0.250  1.0
  Er  Er6  1  0.333  0.334  0.167  1.0
  Er  Er7  1  0.667  0.666  0.833  1.0
  Er  Er8  1  0.334  0.333  0.667  1.0
  Er  Er9  1  0.666  0.667  0.333  1.0
  Mo  Mo10  1  0.000  0.000  0.500  1.0
  Mo  Mo11  1  0.000  0.000  0.000  1.0
  O  O12  1  0.979  0.541  0.240  1.0
  O  O13  1  0.290  0.880  0.917  1.0
  O  O14  1  0.677  0.186  0.567  1.0
  O  O15  1  0.710  0.120  0.083  1.0
  O  O16  1  0.021  0.459  0.760  1.0
  O  O17  1  0.323  0.814  0.433  1.0
  O  O18  1  0.541  0.979  0.740  1.0
  O  O19  1  0.880  0.290  0.417  1.0
  O  O20  1  0.186  0.677  0.067  1.0
  O  O21  1  0.459  0.021  0.260  1.0
  O  O22  1  0.814  0.323  0.933  1.0
  O  O23  1  0.120  0.710  0.583  1.0
  O  O24  1  0.154  0.153  0.075  1.0
  O  O25  1  0.499  0.501  0.750  1.0
  O  O26  1  0.847  0.846  0.425  1.0
  O  O27  1  0.846  0.847  0.925  1.0
  O  O28  1  0.153  0.154  0.575  1.0
  O  O29  1  0.501  0.499  0.250  1.0
[/CIF]
.
The compound described by Ba3Er2MoO9 crystallizes in the monoclinic C2/c space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to one O(5), two equivalent O(1), three equivalent O(2), three equivalent O(3), and three equivalent O(4) atoms to form distorted BaO12 cuboctahedra that share corners with three equivalent Ba(2)O12 cuboctahedra, corners with nine equivalent Ba(1)O12 cuboctahedra, faces with three equivalent Ba(1)O12 cuboctahedra, faces with three equivalent Ba(2)O12 cuboctahedra, faces with three equivalent Mo(1)O6 octahedra, and faces with five equivalent Er(1)O6 octahedra. In the second Ba site, Ba(2) is bonded to two equivalent O(2), two equivalent O(3), two equivalent O(4), two equivalent O(5), and four equivalent O(1) atoms to form BaO12 cuboctahedra that share corners with six equivalent Ba(1)O12 cuboctahedra, corners with six equivalent Ba(2)O12 cuboctahedra, faces with six equivalent Ba(1)O12 cuboctahedra, faces with two equivalent Mo(1)O6 octahedra, and faces with six equivalent Er(1)O6 octahedra. Er(1) is bonded to one O(2), one O(3), one O(4), one O(5), and two equivalent O(1) atoms to form ErO6 octahedra that share corners with three equivalent Er(1)O6 octahedra, corners with three equivalent Mo(1)O6 octahedra, faces with three equivalent Ba(2)O12 cuboctahedra, and faces with five equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-14°. Mo(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form MoO6 octahedra that share corners with six equivalent Er(1)O6 octahedra, faces with two equivalent Ba(2)O12 cuboctahedra, and faces with six equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 1-12°. There are five inequivalent O sites. In the first O site, O(4) is bonded in a distorted linear geometry to one Ba(2), three equivalent Ba(1), one Er(1), and one Mo(1) atom. In the second O site, O(5) is bonded in a distorted linear geometry to two equivalent Ba(1), two equivalent Ba(2), and two equivalent Er(1) atoms. In the third O site, O(1) is bonded in a 2-coordinate geometry to two equivalent Ba(1), two equivalent Ba(2), and two equivalent Er(1) atoms. In the fourth O site, O(2) is bonded in a 2-coordinate geometry to one Ba(2), three equivalent Ba(1), one Er(1), and one Mo(1) atom. In the fifth O site, O(3) is bonded in a 2-coordinate geometry to one Ba(2), three equivalent Ba(1), one Er(1), and one Mo(1) atom. is represented by the CIF file [CIF]
data_Ba3Er2MoO9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.065
_cell_length_b   6.065
_cell_length_c   14.843
_cell_angle_alpha   89.758
_cell_angle_beta   89.758
_cell_angle_gamma   59.833
_symmetry_Int_Tables_number   1
_cell_volume   472.012
_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
  Ba  Ba0  1  0.668  0.665  0.088  1.0
  Ba  Ba1  1  0.998  0.002  0.750  1.0
  Ba  Ba2  1  0.335  0.332  0.412  1.0
  Ba  Ba3  1  0.332  0.335  0.912  1.0
  Ba  Ba4  1  0.665  0.668  0.588  1.0
  Ba  Ba5  1  0.002  0.998  0.250  1.0
  Er  Er6  1  0.333  0.334  0.167  1.0
  Er  Er7  1  0.667  0.666  0.833  1.0
  Er  Er8  1  0.334  0.333  0.667  1.0
  Er  Er9  1  0.666  0.667  0.333  1.0
  Mo  Mo10  1  0.000  0.000  0.500  1.0
  Mo  Mo11  1  0.000  0.000  0.000  1.0
  O  O12  1  0.979  0.541  0.240  1.0
  O  O13  1  0.290  0.880  0.917  1.0
  O  O14  1  0.677  0.186  0.567  1.0
  O  O15  1  0.710  0.120  0.083  1.0
  O  O16  1  0.021  0.459  0.760  1.0
  O  O17  1  0.323  0.814  0.433  1.0
  O  O18  1  0.541  0.979  0.740  1.0
  O  O19  1  0.880  0.290  0.417  1.0
  O  O20  1  0.186  0.677  0.067  1.0
  O  O21  1  0.459  0.021  0.260  1.0
  O  O22  1  0.814  0.323  0.933  1.0
  O  O23  1  0.120  0.710  0.583  1.0
  O  O24  1  0.154  0.153  0.075  1.0
  O  O25  1  0.499  0.501  0.750  1.0
  O  O26  1  0.847  0.846  0.425  1.0
  O  O27  1  0.846  0.847  0.925  1.0
  O  O28  1  0.153  0.154  0.575  1.0
  O  O29  1  0.501  0.499  0.250  1.0
[/CIF]
.