The compound described by Y2O3 crystallizes in the monoclinic P2_1/m space group. There are four inequivalent Y sites. In the first Y site, Y(1) is bonded in a 7-coordinate geometry to one O(3), one O(4), two equivalent O(2), and three equivalent O(1) atoms. In the second Y site, Y(2) is bonded in a 8-coordinate geometry to one O(4), two equivalent O(3), two equivalent O(5), and three equivalent O(2) atoms. In the third Y site, Y(3) is bonded to one O(1), two equivalent O(3), and three equivalent O(6) atoms to form a mixture of corner and edge-sharing YO6 octahedra. The corner-sharing octahedral tilt angles are 62°. In the fourth Y site, Y(4) is bonded to one O(6), two equivalent O(4), and three equivalent O(5) atoms to form a mixture of corner and edge-sharing YO6 octahedra. The corner-sharing octahedral tilt angles are 62°. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Y(3) and three equivalent Y(1) atoms to form OY4 tetrahedra that share  a cornercorner with one O(3)Y5 square pyramid, corners with two equivalent O(1)Y4 tetrahedra, corners with three equivalent O(6)Y4 tetrahedra, corners with four equivalent O(2)Y5 trigonal bipyramids, corners with three equivalent O(4)Y4 trigonal pyramids, edges with two equivalent O(3)Y5 square pyramids, edges with two equivalent O(1)Y4 tetrahedra, and  an edgeedge with one O(2)Y5 trigonal bipyramid. In the second O site, O(2) is bonded to two equivalent Y(1) and three equivalent Y(2) atoms to form distorted OY5 trigonal bipyramids that share corners with two equivalent O(3)Y5 square pyramids, corners with four equivalent O(5)Y5 square pyramids, corners with four equivalent O(1)Y4 tetrahedra,  a cornercorner with one O(4)Y4 trigonal pyramid,  an edgeedge with one O(5)Y5 square pyramid, edges with three equivalent O(3)Y5 square pyramids,  an edgeedge with one O(1)Y4 tetrahedra, edges with four equivalent O(2)Y5 trigonal bipyramids, and edges with two equivalent O(4)Y4 trigonal pyramids. In the third O site, O(3) is bonded to one Y(1), two equivalent Y(2), and two equivalent Y(3) atoms to form OY5 square pyramids that share corners with two equivalent O(5)Y5 square pyramids,  a cornercorner with one O(1)Y4 tetrahedra, corners with four equivalent O(6)Y4 tetrahedra, corners with two equivalent O(2)Y5 trigonal bipyramids, corners with three equivalent O(4)Y4 trigonal pyramids,  an edgeedge with one O(5)Y5 square pyramid, edges with two equivalent O(3)Y5 square pyramids,  an edgeedge with one O(6)Y4 tetrahedra, edges with two equivalent O(1)Y4 tetrahedra, and edges with three equivalent O(2)Y5 trigonal bipyramids. In the fourth O site, O(4) is bonded to one Y(1), one Y(2), and two equivalent Y(4) atoms to form distorted OY4 trigonal pyramids that share corners with two equivalent O(5)Y5 square pyramids, corners with three equivalent O(3)Y5 square pyramids, corners with two equivalent O(6)Y4 tetrahedra, corners with three equivalent O(1)Y4 tetrahedra,  a cornercorner with one O(2)Y5 trigonal bipyramid, corners with two equivalent O(4)Y4 trigonal pyramids, edges with three equivalent O(5)Y5 square pyramids, and edges with two equivalent O(2)Y5 trigonal bipyramids. In the fifth O site, O(5) is bonded to two equivalent Y(2) and three equivalent Y(4) atoms to form OY5 square pyramids that share corners with two equivalent O(3)Y5 square pyramids, corners with three equivalent O(6)Y4 tetrahedra, corners with four equivalent O(2)Y5 trigonal bipyramids, corners with two equivalent O(4)Y4 trigonal pyramids,  an edgeedge with one O(3)Y5 square pyramid, edges with four equivalent O(5)Y5 square pyramids,  an edgeedge with one O(2)Y5 trigonal bipyramid, and edges with three equivalent O(4)Y4 trigonal pyramids. In the sixth O site, O(6) is bonded to one Y(4) and three equivalent Y(3) atoms to form OY4 tetrahedra that share corners with three equivalent O(5)Y5 square pyramids, corners with four equivalent O(3)Y5 square pyramids, corners with two equivalent O(6)Y4 tetrahedra, corners with three equivalent O(1)Y4 tetrahedra, corners with two equivalent O(4)Y4 trigonal pyramids,  an edgeedge with one O(3)Y5 square pyramid, and edges with two equivalent O(6)Y4 tetrahedra. is represented by the CIF file [CIF]
data_Y2O3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.420
_cell_length_b   9.203
_cell_length_c   9.360
_cell_angle_alpha   73.414
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   282.352
_cell_formula_units_Z   4
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  0.250  0.820  0.012  1.0
  Y  Y1  1  0.250  0.451  0.184  1.0
  Y  Y2  1  0.250  0.061  0.329  1.0
  Y  Y3  1  0.750  0.666  0.413  1.0
  Y  Y4  1  0.250  0.334  0.587  1.0
  Y  Y5  1  0.750  0.939  0.671  1.0
  Y  Y6  1  0.750  0.549  0.816  1.0
  Y  Y7  1  0.750  0.180  0.988  1.0
  O  O8  1  0.250  0.036  0.101  1.0
  O  O9  1  0.750  0.606  0.046  1.0
  O  O10  1  0.750  0.236  0.222  1.0
  O  O11  1  0.250  0.690  0.255  1.0
  O  O12  1  0.750  0.421  0.404  1.0
  O  O13  1  0.250  0.095  0.567  1.0
  O  O14  1  0.750  0.905  0.433  1.0
  O  O15  1  0.250  0.579  0.596  1.0
  O  O16  1  0.750  0.310  0.745  1.0
  O  O17  1  0.250  0.764  0.778  1.0
  O  O18  1  0.250  0.394  0.954  1.0
  O  O19  1  0.750  0.964  0.899  1.0
[/CIF]
.
The compound described by Y2O3 crystallizes in the monoclinic P2_1/m space group. There are four inequivalent Y sites. In the first Y site, Y(1) is bonded in a 7-coordinate geometry to one O(3), one O(4), two equivalent O(2), and three equivalent O(1) atoms. In the second Y site, Y(2) is bonded in a 8-coordinate geometry to one O(4), two equivalent O(3), two equivalent O(5), and three equivalent O(2) atoms. In the third Y site, Y(3) is bonded to one O(1), two equivalent O(3), and three equivalent O(6) atoms to form a mixture of corner and edge-sharing YO6 octahedra. The corner-sharing octahedral tilt angles are 62°. In the fourth Y site, Y(4) is bonded to one O(6), two equivalent O(4), and three equivalent O(5) atoms to form a mixture of corner and edge-sharing YO6 octahedra. The corner-sharing octahedral tilt angles are 62°. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Y(3) and three equivalent Y(1) atoms to form OY4 tetrahedra that share  a cornercorner with one O(3)Y5 square pyramid, corners with two equivalent O(1)Y4 tetrahedra, corners with three equivalent O(6)Y4 tetrahedra, corners with four equivalent O(2)Y5 trigonal bipyramids, corners with three equivalent O(4)Y4 trigonal pyramids, edges with two equivalent O(3)Y5 square pyramids, edges with two equivalent O(1)Y4 tetrahedra, and  an edgeedge with one O(2)Y5 trigonal bipyramid. In the second O site, O(2) is bonded to two equivalent Y(1) and three equivalent Y(2) atoms to form distorted OY5 trigonal bipyramids that share corners with two equivalent O(3)Y5 square pyramids, corners with four equivalent O(5)Y5 square pyramids, corners with four equivalent O(1)Y4 tetrahedra,  a cornercorner with one O(4)Y4 trigonal pyramid,  an edgeedge with one O(5)Y5 square pyramid, edges with three equivalent O(3)Y5 square pyramids,  an edgeedge with one O(1)Y4 tetrahedra, edges with four equivalent O(2)Y5 trigonal bipyramids, and edges with two equivalent O(4)Y4 trigonal pyramids. In the third O site, O(3) is bonded to one Y(1), two equivalent Y(2), and two equivalent Y(3) atoms to form OY5 square pyramids that share corners with two equivalent O(5)Y5 square pyramids,  a cornercorner with one O(1)Y4 tetrahedra, corners with four equivalent O(6)Y4 tetrahedra, corners with two equivalent O(2)Y5 trigonal bipyramids, corners with three equivalent O(4)Y4 trigonal pyramids,  an edgeedge with one O(5)Y5 square pyramid, edges with two equivalent O(3)Y5 square pyramids,  an edgeedge with one O(6)Y4 tetrahedra, edges with two equivalent O(1)Y4 tetrahedra, and edges with three equivalent O(2)Y5 trigonal bipyramids. In the fourth O site, O(4) is bonded to one Y(1), one Y(2), and two equivalent Y(4) atoms to form distorted OY4 trigonal pyramids that share corners with two equivalent O(5)Y5 square pyramids, corners with three equivalent O(3)Y5 square pyramids, corners with two equivalent O(6)Y4 tetrahedra, corners with three equivalent O(1)Y4 tetrahedra,  a cornercorner with one O(2)Y5 trigonal bipyramid, corners with two equivalent O(4)Y4 trigonal pyramids, edges with three equivalent O(5)Y5 square pyramids, and edges with two equivalent O(2)Y5 trigonal bipyramids. In the fifth O site, O(5) is bonded to two equivalent Y(2) and three equivalent Y(4) atoms to form OY5 square pyramids that share corners with two equivalent O(3)Y5 square pyramids, corners with three equivalent O(6)Y4 tetrahedra, corners with four equivalent O(2)Y5 trigonal bipyramids, corners with two equivalent O(4)Y4 trigonal pyramids,  an edgeedge with one O(3)Y5 square pyramid, edges with four equivalent O(5)Y5 square pyramids,  an edgeedge with one O(2)Y5 trigonal bipyramid, and edges with three equivalent O(4)Y4 trigonal pyramids. In the sixth O site, O(6) is bonded to one Y(4) and three equivalent Y(3) atoms to form OY4 tetrahedra that share corners with three equivalent O(5)Y5 square pyramids, corners with four equivalent O(3)Y5 square pyramids, corners with two equivalent O(6)Y4 tetrahedra, corners with three equivalent O(1)Y4 tetrahedra, corners with two equivalent O(4)Y4 trigonal pyramids,  an edgeedge with one O(3)Y5 square pyramid, and edges with two equivalent O(6)Y4 tetrahedra. is represented by the CIF file [CIF]
data_Y2O3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.420
_cell_length_b   9.203
_cell_length_c   9.360
_cell_angle_alpha   73.414
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   282.352
_cell_formula_units_Z   4
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  0.250  0.820  0.012  1.0
  Y  Y1  1  0.250  0.451  0.184  1.0
  Y  Y2  1  0.250  0.061  0.329  1.0
  Y  Y3  1  0.750  0.666  0.413  1.0
  Y  Y4  1  0.250  0.334  0.587  1.0
  Y  Y5  1  0.750  0.939  0.671  1.0
  Y  Y6  1  0.750  0.549  0.816  1.0
  Y  Y7  1  0.750  0.180  0.988  1.0
  O  O8  1  0.250  0.036  0.101  1.0
  O  O9  1  0.750  0.606  0.046  1.0
  O  O10  1  0.750  0.236  0.222  1.0
  O  O11  1  0.250  0.690  0.255  1.0
  O  O12  1  0.750  0.421  0.404  1.0
  O  O13  1  0.250  0.095  0.567  1.0
  O  O14  1  0.750  0.905  0.433  1.0
  O  O15  1  0.250  0.579  0.596  1.0
  O  O16  1  0.750  0.310  0.745  1.0
  O  O17  1  0.250  0.764  0.778  1.0
  O  O18  1  0.250  0.394  0.954  1.0
  O  O19  1  0.750  0.964  0.899  1.0
[/CIF]
.