The material described by La2Al4O9 crystallizes in the orthorhombic Pbam space group. La(1) is bonded in a 6-coordinate geometry to two equivalent O(4) and four equivalent O(2) atoms. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form AlO6 octahedra that share corners with four equivalent Al(2)O4 tetrahedra and edges with two equivalent Al(1)O6 octahedra. In the second Al site, Al(2) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form AlO4 tetrahedra that share corners with four equivalent Al(1)O6 octahedra and  a cornercorner with one Al(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 47-55°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to two equivalent Al(2) atoms. In the second O site, O(2) is bonded to two equivalent La(1), one Al(1), and one Al(2) atom to form a mixture of distorted corner and edge-sharing OLa2Al2 tetrahedra. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Al(2) and two equivalent Al(1) atoms. In the fourth O site, O(4) is bonded to two equivalent La(1) and two equivalent Al(1) atoms to form a mixture of distorted corner and edge-sharing OLa2Al2 tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_La2Al4O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.724
_cell_length_b   7.671
_cell_length_c   8.470
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   371.894
_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
  La  La0  1  0.000  0.151  0.178  1.0
  La  La1  1  0.000  0.349  0.678  1.0
  La  La2  1  0.000  0.651  0.322  1.0
  La  La3  1  0.000  0.849  0.822  1.0
  Al  Al4  1  0.259  0.000  0.500  1.0
  Al  Al5  1  0.741  0.000  0.500  1.0
  Al  Al6  1  0.500  0.142  0.839  1.0
  Al  Al7  1  0.500  0.358  0.339  1.0
  Al  Al8  1  0.259  0.500  0.000  1.0
  Al  Al9  1  0.741  0.500  0.000  1.0
  Al  Al10  1  0.500  0.642  0.661  1.0
  Al  Al11  1  0.500  0.858  0.161  1.0
  O  O12  1  0.500  0.000  0.000  1.0
  O  O13  1  0.751  0.104  0.719  1.0
  O  O14  1  0.249  0.104  0.719  1.0
  O  O15  1  0.500  0.147  0.427  1.0
  O  O16  1  0.000  0.154  0.449  1.0
  O  O17  1  0.000  0.346  0.949  1.0
  O  O18  1  0.500  0.353  0.927  1.0
  O  O19  1  0.249  0.396  0.219  1.0
  O  O20  1  0.751  0.396  0.219  1.0
  O  O21  1  0.500  0.500  0.500  1.0
  O  O22  1  0.249  0.604  0.781  1.0
  O  O23  1  0.751  0.604  0.781  1.0
  O  O24  1  0.500  0.647  0.073  1.0
  O  O25  1  0.000  0.654  0.051  1.0
  O  O26  1  0.000  0.846  0.551  1.0
  O  O27  1  0.500  0.853  0.573  1.0
  O  O28  1  0.249  0.896  0.281  1.0
  O  O29  1  0.751  0.896  0.281  1.0
[/CIF]
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The material described by La2Al4O9 crystallizes in the orthorhombic Pbam space group. La(1) is bonded in a 6-coordinate geometry to two equivalent O(4) and four equivalent O(2) atoms. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form AlO6 octahedra that share corners with four equivalent Al(2)O4 tetrahedra and edges with two equivalent Al(1)O6 octahedra. In the second Al site, Al(2) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form AlO4 tetrahedra that share corners with four equivalent Al(1)O6 octahedra and  a cornercorner with one Al(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 47-55°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to two equivalent Al(2) atoms. In the second O site, O(2) is bonded to two equivalent La(1), one Al(1), and one Al(2) atom to form a mixture of distorted corner and edge-sharing OLa2Al2 tetrahedra. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Al(2) and two equivalent Al(1) atoms. In the fourth O site, O(4) is bonded to two equivalent La(1) and two equivalent Al(1) atoms to form a mixture of distorted corner and edge-sharing OLa2Al2 tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_La2Al4O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.724
_cell_length_b   7.671
_cell_length_c   8.470
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   371.894
_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
  La  La0  1  0.000  0.151  0.178  1.0
  La  La1  1  0.000  0.349  0.678  1.0
  La  La2  1  0.000  0.651  0.322  1.0
  La  La3  1  0.000  0.849  0.822  1.0
  Al  Al4  1  0.259  0.000  0.500  1.0
  Al  Al5  1  0.741  0.000  0.500  1.0
  Al  Al6  1  0.500  0.142  0.839  1.0
  Al  Al7  1  0.500  0.358  0.339  1.0
  Al  Al8  1  0.259  0.500  0.000  1.0
  Al  Al9  1  0.741  0.500  0.000  1.0
  Al  Al10  1  0.500  0.642  0.661  1.0
  Al  Al11  1  0.500  0.858  0.161  1.0
  O  O12  1  0.500  0.000  0.000  1.0
  O  O13  1  0.751  0.104  0.719  1.0
  O  O14  1  0.249  0.104  0.719  1.0
  O  O15  1  0.500  0.147  0.427  1.0
  O  O16  1  0.000  0.154  0.449  1.0
  O  O17  1  0.000  0.346  0.949  1.0
  O  O18  1  0.500  0.353  0.927  1.0
  O  O19  1  0.249  0.396  0.219  1.0
  O  O20  1  0.751  0.396  0.219  1.0
  O  O21  1  0.500  0.500  0.500  1.0
  O  O22  1  0.249  0.604  0.781  1.0
  O  O23  1  0.751  0.604  0.781  1.0
  O  O24  1  0.500  0.647  0.073  1.0
  O  O25  1  0.000  0.654  0.051  1.0
  O  O26  1  0.000  0.846  0.551  1.0
  O  O27  1  0.500  0.853  0.573  1.0
  O  O28  1  0.249  0.896  0.281  1.0
  O  O29  1  0.751  0.896  0.281  1.0
[/CIF]
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