The crystal structure described by Sc2O3 crystallizes in the monoclinic C2/m space group. There are three inequivalent Sc sites. In the first Sc site, Sc(1) is bonded to one O(1), one O(3), two equivalent O(4), and two equivalent O(5) atoms to form a mixture of corner and edge-sharing ScO6 octahedra. The corner-sharing octahedra are not tilted. In the second Sc site, Sc(2) is bonded in a 7-coordinate geometry to two equivalent O(3), two equivalent O(5), and three equivalent O(2) atoms. In the third Sc site, Sc(3) is bonded in a 7-coordinate geometry to one O(2), one O(4), two equivalent O(3), and three equivalent O(1) atoms. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Sc(1) and three equivalent Sc(3) atoms to form OSc4 tetrahedra that share  a cornercorner with one O(4)Sc6 octahedra, corners with two equivalent O(1)Sc4 tetrahedra, corners with two equivalent O(5)Sc4 tetrahedra, corners with five equivalent O(3)Sc5 trigonal bipyramids, corners with three equivalent O(2)Sc4 trigonal pyramids, edges with two equivalent O(4)Sc6 octahedra, edges with two equivalent O(1)Sc4 tetrahedra, and  an edgeedge with one O(3)Sc5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 47°. In the second O site, O(2) is bonded to one Sc(3) and three equivalent Sc(2) atoms to form distorted OSc4 trigonal pyramids that share  a cornercorner with one O(4)Sc6 octahedra, corners with three equivalent O(1)Sc4 tetrahedra, corners with six equivalent O(5)Sc4 tetrahedra, corners with two equivalent O(3)Sc5 trigonal bipyramids, corners with two equivalent O(2)Sc4 trigonal pyramids, edges with three equivalent O(3)Sc5 trigonal bipyramids, and edges with two equivalent O(2)Sc4 trigonal pyramids. The corner-sharing octahedral tilt angles are 39°. In the third O site, O(3) is bonded to one Sc(1), two equivalent Sc(2), and two equivalent Sc(3) atoms to form distorted OSc5 trigonal bipyramids that share corners with two equivalent O(5)Sc4 tetrahedra, corners with five equivalent O(1)Sc4 tetrahedra, corners with two equivalent O(2)Sc4 trigonal pyramids, edges with two equivalent O(4)Sc6 octahedra,  an edgeedge with one O(1)Sc4 tetrahedra, edges with two equivalent O(5)Sc4 tetrahedra, edges with two equivalent O(3)Sc5 trigonal bipyramids, and edges with three equivalent O(2)Sc4 trigonal pyramids. In the fourth O site, O(4) is bonded to two equivalent Sc(3) and four equivalent Sc(1) atoms to form OSc6 octahedra that share corners with two equivalent O(1)Sc4 tetrahedra, corners with four equivalent O(5)Sc4 tetrahedra, corners with two equivalent O(2)Sc4 trigonal pyramids, edges with two equivalent O(4)Sc6 octahedra, edges with two equivalent O(5)Sc4 tetrahedra, edges with four equivalent O(1)Sc4 tetrahedra, and edges with four equivalent O(3)Sc5 trigonal bipyramids. In the fifth O site, O(5) is bonded to two equivalent Sc(1) and two equivalent Sc(2) atoms to form distorted OSc4 tetrahedra that share corners with two equivalent O(4)Sc6 octahedra, corners with two equivalent O(1)Sc4 tetrahedra, corners with two equivalent O(5)Sc4 tetrahedra, corners with two equivalent O(3)Sc5 trigonal bipyramids, corners with six equivalent O(2)Sc4 trigonal pyramids,  an edgeedge with one O(4)Sc6 octahedra,  an edgeedge with one O(5)Sc4 tetrahedra, and edges with two equivalent O(3)Sc5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 11°. is represented by the CIF file [CIF]
data_Sc2O3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.201
_cell_length_b   6.825
_cell_length_c   8.016
_cell_angle_alpha   100.257
_cell_angle_beta   90.000
_cell_angle_gamma   103.563
_symmetry_Int_Tables_number   1
_cell_volume   167.396
_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
  Sc  Sc0  1  0.969  0.937  0.184  1.0
  Sc  Sc1  1  0.636  0.272  0.486  1.0
  Sc  Sc2  1  0.308  0.617  0.863  1.0
  Sc  Sc3  1  0.031  0.063  0.816  1.0
  Sc  Sc4  1  0.364  0.728  0.514  1.0
  Sc  Sc5  1  0.692  0.383  0.137  1.0
  O  O6  1  0.174  0.347  0.965  1.0
  O  O7  1  0.826  0.653  0.035  1.0
  O  O8  1  0.210  0.419  0.622  1.0
  O  O9  1  0.874  0.748  0.720  1.0
  O  O10  1  0.500  0.000  0.000  1.0
  O  O11  1  0.790  0.581  0.378  1.0
  O  O12  1  0.467  0.934  0.342  1.0
  O  O13  1  0.126  0.252  0.280  1.0
  O  O14  1  0.533  0.066  0.658  1.0
[/CIF]
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The crystal structure described by Sc2O3 crystallizes in the monoclinic C2/m space group. There are three inequivalent Sc sites. In the first Sc site, Sc(1) is bonded to one O(1), one O(3), two equivalent O(4), and two equivalent O(5) atoms to form a mixture of corner and edge-sharing ScO6 octahedra. The corner-sharing octahedra are not tilted. In the second Sc site, Sc(2) is bonded in a 7-coordinate geometry to two equivalent O(3), two equivalent O(5), and three equivalent O(2) atoms. In the third Sc site, Sc(3) is bonded in a 7-coordinate geometry to one O(2), one O(4), two equivalent O(3), and three equivalent O(1) atoms. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Sc(1) and three equivalent Sc(3) atoms to form OSc4 tetrahedra that share  a cornercorner with one O(4)Sc6 octahedra, corners with two equivalent O(1)Sc4 tetrahedra, corners with two equivalent O(5)Sc4 tetrahedra, corners with five equivalent O(3)Sc5 trigonal bipyramids, corners with three equivalent O(2)Sc4 trigonal pyramids, edges with two equivalent O(4)Sc6 octahedra, edges with two equivalent O(1)Sc4 tetrahedra, and  an edgeedge with one O(3)Sc5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 47°. In the second O site, O(2) is bonded to one Sc(3) and three equivalent Sc(2) atoms to form distorted OSc4 trigonal pyramids that share  a cornercorner with one O(4)Sc6 octahedra, corners with three equivalent O(1)Sc4 tetrahedra, corners with six equivalent O(5)Sc4 tetrahedra, corners with two equivalent O(3)Sc5 trigonal bipyramids, corners with two equivalent O(2)Sc4 trigonal pyramids, edges with three equivalent O(3)Sc5 trigonal bipyramids, and edges with two equivalent O(2)Sc4 trigonal pyramids. The corner-sharing octahedral tilt angles are 39°. In the third O site, O(3) is bonded to one Sc(1), two equivalent Sc(2), and two equivalent Sc(3) atoms to form distorted OSc5 trigonal bipyramids that share corners with two equivalent O(5)Sc4 tetrahedra, corners with five equivalent O(1)Sc4 tetrahedra, corners with two equivalent O(2)Sc4 trigonal pyramids, edges with two equivalent O(4)Sc6 octahedra,  an edgeedge with one O(1)Sc4 tetrahedra, edges with two equivalent O(5)Sc4 tetrahedra, edges with two equivalent O(3)Sc5 trigonal bipyramids, and edges with three equivalent O(2)Sc4 trigonal pyramids. In the fourth O site, O(4) is bonded to two equivalent Sc(3) and four equivalent Sc(1) atoms to form OSc6 octahedra that share corners with two equivalent O(1)Sc4 tetrahedra, corners with four equivalent O(5)Sc4 tetrahedra, corners with two equivalent O(2)Sc4 trigonal pyramids, edges with two equivalent O(4)Sc6 octahedra, edges with two equivalent O(5)Sc4 tetrahedra, edges with four equivalent O(1)Sc4 tetrahedra, and edges with four equivalent O(3)Sc5 trigonal bipyramids. In the fifth O site, O(5) is bonded to two equivalent Sc(1) and two equivalent Sc(2) atoms to form distorted OSc4 tetrahedra that share corners with two equivalent O(4)Sc6 octahedra, corners with two equivalent O(1)Sc4 tetrahedra, corners with two equivalent O(5)Sc4 tetrahedra, corners with two equivalent O(3)Sc5 trigonal bipyramids, corners with six equivalent O(2)Sc4 trigonal pyramids,  an edgeedge with one O(4)Sc6 octahedra,  an edgeedge with one O(5)Sc4 tetrahedra, and edges with two equivalent O(3)Sc5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 11°. is represented by the CIF file [CIF]
data_Sc2O3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.201
_cell_length_b   6.825
_cell_length_c   8.016
_cell_angle_alpha   100.257
_cell_angle_beta   90.000
_cell_angle_gamma   103.563
_symmetry_Int_Tables_number   1
_cell_volume   167.396
_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
  Sc  Sc0  1  0.969  0.937  0.184  1.0
  Sc  Sc1  1  0.636  0.272  0.486  1.0
  Sc  Sc2  1  0.308  0.617  0.863  1.0
  Sc  Sc3  1  0.031  0.063  0.816  1.0
  Sc  Sc4  1  0.364  0.728  0.514  1.0
  Sc  Sc5  1  0.692  0.383  0.137  1.0
  O  O6  1  0.174  0.347  0.965  1.0
  O  O7  1  0.826  0.653  0.035  1.0
  O  O8  1  0.210  0.419  0.622  1.0
  O  O9  1  0.874  0.748  0.720  1.0
  O  O10  1  0.500  0.000  0.000  1.0
  O  O11  1  0.790  0.581  0.378  1.0
  O  O12  1  0.467  0.934  0.342  1.0
  O  O13  1  0.126  0.252  0.280  1.0
  O  O14  1  0.533  0.066  0.658  1.0
[/CIF]
.