The material structure described by Al2HfO5 crystallizes in the orthorhombic Cmcm space group. Hf(1) is bonded in a 6-coordinate geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. Al(1) is bonded to one O(3), two equivalent O(2), and three equivalent O(1) atoms to form a mixture of distorted corner and edge-sharing AlO6 octahedra. The corner-sharing octahedral tilt angles range from 33-44°. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Hf(1) and three equivalent Al(1) atoms to form a mixture of distorted corner and edge-sharing OHfAl3 trigonal pyramids. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Hf(1) and two equivalent Al(1) atoms. In the third O site, O(3) is bonded in a 4-coordinate geometry to two equivalent Hf(1) and two equivalent Al(1) atoms. is represented by the CIF file [CIF]
data_HfAl2O5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.141
_cell_length_b   5.141
_cell_length_c   10.288
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   138.250
_symmetry_Int_Tables_number   1
_cell_volume   181.082
_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
  Hf  Hf0  1  0.813  0.187  0.250  1.0
  Hf  Hf1  1  0.187  0.813  0.750  1.0
  Al  Al2  1  0.863  0.137  0.953  1.0
  Al  Al3  1  0.137  0.863  0.047  1.0
  Al  Al4  1  0.863  0.137  0.547  1.0
  Al  Al5  1  0.137  0.863  0.453  1.0
  O  O6  1  0.691  0.309  0.063  1.0
  O  O7  1  0.309  0.691  0.937  1.0
  O  O8  1  0.309  0.691  0.563  1.0
  O  O9  1  0.691  0.309  0.437  1.0
  O  O10  1  0.960  0.040  0.113  1.0
  O  O11  1  0.040  0.960  0.887  1.0
  O  O12  1  0.225  0.775  0.250  1.0
  O  O13  1  0.775  0.225  0.750  1.0
  O  O14  1  0.960  0.040  0.387  1.0
  O  O15  1  0.040  0.960  0.613  1.0
[/CIF]
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The material structure described by Al2HfO5 crystallizes in the orthorhombic Cmcm space group. Hf(1) is bonded in a 6-coordinate geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. Al(1) is bonded to one O(3), two equivalent O(2), and three equivalent O(1) atoms to form a mixture of distorted corner and edge-sharing AlO6 octahedra. The corner-sharing octahedral tilt angles range from 33-44°. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Hf(1) and three equivalent Al(1) atoms to form a mixture of distorted corner and edge-sharing OHfAl3 trigonal pyramids. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Hf(1) and two equivalent Al(1) atoms. In the third O site, O(3) is bonded in a 4-coordinate geometry to two equivalent Hf(1) and two equivalent Al(1) atoms. is represented by the CIF file [CIF]
data_HfAl2O5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.141
_cell_length_b   5.141
_cell_length_c   10.288
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   138.250
_symmetry_Int_Tables_number   1
_cell_volume   181.082
_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
  Hf  Hf0  1  0.813  0.187  0.250  1.0
  Hf  Hf1  1  0.187  0.813  0.750  1.0
  Al  Al2  1  0.863  0.137  0.953  1.0
  Al  Al3  1  0.137  0.863  0.047  1.0
  Al  Al4  1  0.863  0.137  0.547  1.0
  Al  Al5  1  0.137  0.863  0.453  1.0
  O  O6  1  0.691  0.309  0.063  1.0
  O  O7  1  0.309  0.691  0.937  1.0
  O  O8  1  0.309  0.691  0.563  1.0
  O  O9  1  0.691  0.309  0.437  1.0
  O  O10  1  0.960  0.040  0.113  1.0
  O  O11  1  0.040  0.960  0.887  1.0
  O  O12  1  0.225  0.775  0.250  1.0
  O  O13  1  0.775  0.225  0.750  1.0
  O  O14  1  0.960  0.040  0.387  1.0
  O  O15  1  0.040  0.960  0.613  1.0
[/CIF]
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