The material described by Y2O3 crystallizes in the monoclinic C2/m space group. There are three inequivalent Y sites. In the first Y site, Y(1) is bonded in a 7-coordinate geometry to two equivalent O(1), two equivalent O(4), and three equivalent O(3) atoms. In the second Y site, Y(2) is bonded to one O(1), one O(2), two equivalent O(4), and two equivalent O(5) atoms to form a mixture of distorted corner and edge-sharing YO6 octahedra. The corner-sharing octahedra are not tilted. In the third Y site, Y(3) is bonded in a 7-coordinate geometry to one O(3), one O(5), two equivalent O(1), and three equivalent O(2) atoms. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Y(2), two equivalent Y(1), and two equivalent Y(3) atoms to form distorted OY5 square pyramids that share corners with two equivalent O(4)Y4 tetrahedra, corners with five equivalent O(2)Y4 tetrahedra, corners with two equivalent O(3)Y4 trigonal pyramids, edges with two equivalent O(5)Y6 octahedra, edges with two equivalent O(1)Y5 square pyramids,  an edgeedge with one O(2)Y4 tetrahedra, edges with two equivalent O(4)Y4 tetrahedra, and edges with three equivalent O(3)Y4 trigonal pyramids. In the second O site, O(2) is bonded to one Y(2) and three equivalent Y(3) atoms to form OY4 tetrahedra that share  a cornercorner with one O(5)Y6 octahedra, corners with five equivalent O(1)Y5 square pyramids, corners with two equivalent O(2)Y4 tetrahedra, corners with two equivalent O(4)Y4 tetrahedra, corners with three equivalent O(3)Y4 trigonal pyramids, edges with two equivalent O(5)Y6 octahedra,  an edgeedge with one O(1)Y5 square pyramid, and edges with two equivalent O(2)Y4 tetrahedra. The corner-sharing octahedral tilt angles are 49°. In the third O site, O(3) is bonded to one Y(3) and three equivalent Y(1) atoms to form distorted OY4 trigonal pyramids that share  a cornercorner with one O(5)Y6 octahedra, corners with two equivalent O(1)Y5 square pyramids, corners with three equivalent O(2)Y4 tetrahedra, corners with six equivalent O(4)Y4 tetrahedra, corners with two equivalent O(3)Y4 trigonal pyramids, edges with three equivalent O(1)Y5 square pyramids, and edges with two equivalent O(3)Y4 trigonal pyramids. The corner-sharing octahedral tilt angles are 37°. In the fourth O site, O(4) is bonded to two equivalent Y(1) and two equivalent Y(2) atoms to form OY4 tetrahedra that share corners with two equivalent O(5)Y6 octahedra, corners with two equivalent O(1)Y5 square pyramids, corners with two equivalent O(2)Y4 tetrahedra, corners with two equivalent O(4)Y4 tetrahedra, corners with six equivalent O(3)Y4 trigonal pyramids,  an edgeedge with one O(5)Y6 octahedra, edges with two equivalent O(1)Y5 square pyramids, and  an edgeedge with one O(4)Y4 tetrahedra. The corner-sharing octahedral tilt angles are 14°. In the fifth O site, O(5) is bonded to two equivalent Y(3) and four equivalent Y(2) atoms to form OY6 octahedra that share corners with two equivalent O(2)Y4 tetrahedra, corners with four equivalent O(4)Y4 tetrahedra, corners with two equivalent O(3)Y4 trigonal pyramids, edges with two equivalent O(5)Y6 octahedra, edges with four equivalent O(1)Y5 square pyramids, edges with two equivalent O(4)Y4 tetrahedra, and edges with four equivalent O(2)Y4 tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Y2O3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.488
_cell_length_b   7.184
_cell_length_c   8.614
_cell_angle_alpha   99.842
_cell_angle_beta   90.000
_cell_angle_gamma   104.050
_symmetry_Int_Tables_number   1
_cell_volume   206.116
_cell_formula_units_Z   3
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
  Y  Y0  1  0.635  0.271  0.487  1.0
  Y  Y1  1  0.365  0.729  0.513  1.0
  Y  Y2  1  0.033  0.066  0.813  1.0
  Y  Y3  1  0.691  0.381  0.137  1.0
  Y  Y4  1  0.309  0.619  0.863  1.0
  Y  Y5  1  0.967  0.934  0.187  1.0
  O  O6  1  0.128  0.255  0.282  1.0
  O  O7  1  0.825  0.651  0.030  1.0
  O  O8  1  0.793  0.587  0.377  1.0
  O  O9  1  0.471  0.942  0.343  1.0
  O  O10  1  0.529  0.058  0.657  1.0
  O  O11  1  0.500  0.000  0.000  1.0
  O  O12  1  0.175  0.349  0.970  1.0
  O  O13  1  0.207  0.413  0.623  1.0
  O  O14  1  0.872  0.745  0.718  1.0
[/CIF]
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The material described by Y2O3 crystallizes in the monoclinic C2/m space group. There are three inequivalent Y sites. In the first Y site, Y(1) is bonded in a 7-coordinate geometry to two equivalent O(1), two equivalent O(4), and three equivalent O(3) atoms. In the second Y site, Y(2) is bonded to one O(1), one O(2), two equivalent O(4), and two equivalent O(5) atoms to form a mixture of distorted corner and edge-sharing YO6 octahedra. The corner-sharing octahedra are not tilted. In the third Y site, Y(3) is bonded in a 7-coordinate geometry to one O(3), one O(5), two equivalent O(1), and three equivalent O(2) atoms. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Y(2), two equivalent Y(1), and two equivalent Y(3) atoms to form distorted OY5 square pyramids that share corners with two equivalent O(4)Y4 tetrahedra, corners with five equivalent O(2)Y4 tetrahedra, corners with two equivalent O(3)Y4 trigonal pyramids, edges with two equivalent O(5)Y6 octahedra, edges with two equivalent O(1)Y5 square pyramids,  an edgeedge with one O(2)Y4 tetrahedra, edges with two equivalent O(4)Y4 tetrahedra, and edges with three equivalent O(3)Y4 trigonal pyramids. In the second O site, O(2) is bonded to one Y(2) and three equivalent Y(3) atoms to form OY4 tetrahedra that share  a cornercorner with one O(5)Y6 octahedra, corners with five equivalent O(1)Y5 square pyramids, corners with two equivalent O(2)Y4 tetrahedra, corners with two equivalent O(4)Y4 tetrahedra, corners with three equivalent O(3)Y4 trigonal pyramids, edges with two equivalent O(5)Y6 octahedra,  an edgeedge with one O(1)Y5 square pyramid, and edges with two equivalent O(2)Y4 tetrahedra. The corner-sharing octahedral tilt angles are 49°. In the third O site, O(3) is bonded to one Y(3) and three equivalent Y(1) atoms to form distorted OY4 trigonal pyramids that share  a cornercorner with one O(5)Y6 octahedra, corners with two equivalent O(1)Y5 square pyramids, corners with three equivalent O(2)Y4 tetrahedra, corners with six equivalent O(4)Y4 tetrahedra, corners with two equivalent O(3)Y4 trigonal pyramids, edges with three equivalent O(1)Y5 square pyramids, and edges with two equivalent O(3)Y4 trigonal pyramids. The corner-sharing octahedral tilt angles are 37°. In the fourth O site, O(4) is bonded to two equivalent Y(1) and two equivalent Y(2) atoms to form OY4 tetrahedra that share corners with two equivalent O(5)Y6 octahedra, corners with two equivalent O(1)Y5 square pyramids, corners with two equivalent O(2)Y4 tetrahedra, corners with two equivalent O(4)Y4 tetrahedra, corners with six equivalent O(3)Y4 trigonal pyramids,  an edgeedge with one O(5)Y6 octahedra, edges with two equivalent O(1)Y5 square pyramids, and  an edgeedge with one O(4)Y4 tetrahedra. The corner-sharing octahedral tilt angles are 14°. In the fifth O site, O(5) is bonded to two equivalent Y(3) and four equivalent Y(2) atoms to form OY6 octahedra that share corners with two equivalent O(2)Y4 tetrahedra, corners with four equivalent O(4)Y4 tetrahedra, corners with two equivalent O(3)Y4 trigonal pyramids, edges with two equivalent O(5)Y6 octahedra, edges with four equivalent O(1)Y5 square pyramids, edges with two equivalent O(4)Y4 tetrahedra, and edges with four equivalent O(2)Y4 tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Y2O3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.488
_cell_length_b   7.184
_cell_length_c   8.614
_cell_angle_alpha   99.842
_cell_angle_beta   90.000
_cell_angle_gamma   104.050
_symmetry_Int_Tables_number   1
_cell_volume   206.116
_cell_formula_units_Z   3
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
  Y  Y0  1  0.635  0.271  0.487  1.0
  Y  Y1  1  0.365  0.729  0.513  1.0
  Y  Y2  1  0.033  0.066  0.813  1.0
  Y  Y3  1  0.691  0.381  0.137  1.0
  Y  Y4  1  0.309  0.619  0.863  1.0
  Y  Y5  1  0.967  0.934  0.187  1.0
  O  O6  1  0.128  0.255  0.282  1.0
  O  O7  1  0.825  0.651  0.030  1.0
  O  O8  1  0.793  0.587  0.377  1.0
  O  O9  1  0.471  0.942  0.343  1.0
  O  O10  1  0.529  0.058  0.657  1.0
  O  O11  1  0.500  0.000  0.000  1.0
  O  O12  1  0.175  0.349  0.970  1.0
  O  O13  1  0.207  0.413  0.623  1.0
  O  O14  1  0.872  0.745  0.718  1.0
[/CIF]
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