The material described by LaFeAsO is Parent of FeAs superconductors structured and crystallizes in the triclinic P1 space group. There are four inequivalent La sites. In the first La site, La(1) is bonded in a 4-coordinate geometry to two equivalent As(3), two equivalent As(4), one O(1), one O(2), and two equivalent O(3) atoms. In the second La site, La(2) is bonded in a 4-coordinate geometry to two equivalent As(3), two equivalent As(4), one O(1), one O(2), and two equivalent O(4) atoms. In the third La site, La(3) is bonded in a 4-coordinate geometry to two equivalent As(1), two equivalent As(2), one O(3), one O(4), and two equivalent O(1) atoms. In the fourth La site, La(4) is bonded in a 4-coordinate geometry to two equivalent As(1), two equivalent As(2), one O(3), one O(4), and two equivalent O(2) atoms. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one As(1), one As(2), and two equivalent As(4) atoms to form a mixture of corner and edge-sharing FeAs4 tetrahedra. In the second Fe site, Fe(2) is bonded to one As(3), one As(4), and two equivalent As(2) atoms to form a mixture of corner and edge-sharing FeAs4 tetrahedra. In the third Fe site, Fe(3) is bonded to one As(1), one As(2), and two equivalent As(3) atoms to form a mixture of distorted corner and edge-sharing FeAs4 tetrahedra. In the fourth Fe site, Fe(4) is bonded to one As(3), one As(4), and two equivalent As(1) atoms to form a mixture of distorted corner and edge-sharing FeAs4 tetrahedra. There are four inequivalent As sites. In the first As site, As(1) is bonded in a 8-coordinate geometry to two equivalent La(3), two equivalent La(4), one Fe(1), one Fe(3), and two equivalent Fe(4) atoms. In the second As site, As(2) is bonded in a 8-coordinate geometry to two equivalent La(3), two equivalent La(4), one Fe(1), one Fe(3), and two equivalent Fe(2) atoms. In the third As site, As(3) is bonded in a 8-coordinate geometry to two equivalent La(1), two equivalent La(2), one Fe(2), one Fe(4), and two equivalent Fe(3) atoms. In the fourth As site, As(4) is bonded in a 8-coordinate geometry to two equivalent La(1), two equivalent La(2), one Fe(2), one Fe(4), and two equivalent Fe(1) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded to one La(1), one La(2), and two equivalent La(3) atoms to form a mixture of corner and edge-sharing OLa4 tetrahedra. In the second O site, O(2) is bonded to one La(1), one La(2), and two equivalent La(4) atoms to form a mixture of corner and edge-sharing OLa4 tetrahedra. In the third O site, O(3) is bonded to one La(3), one La(4), and two equivalent La(1) atoms to form a mixture of corner and edge-sharing OLa4 tetrahedra. In the fourth O site, O(4) is bonded to one La(3), one La(4), and two equivalent La(2) atoms to form a mixture of corner and edge-sharing OLa4 tetrahedra. is represented by the CIF file [CIF]
data_LaFeAsO
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.130
_cell_length_b   4.139
_cell_length_c   9.160
_cell_angle_alpha   90.060
_cell_angle_beta   90.412
_cell_angle_gamma   89.974
_symmetry_Int_Tables_number   1
_cell_volume   156.550
_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
  As  As0  1  0.238  0.247  0.670  1.0
  As  As1  1  0.758  0.747  0.330  1.0
  Fe  Fe2  1  0.747  0.254  0.500  1.0
  Fe  Fe3  1  0.257  0.753  0.499  1.0
  La  La4  1  0.252  0.250  0.131  1.0
  La  La5  1  0.748  0.750  0.869  1.0
  O  O6  1  0.750  0.250  1.000  1.0
  O  O7  1  0.250  0.750  0.000  1.0
[/CIF]
.
The material described by LaFeAsO is Parent of FeAs superconductors structured and crystallizes in the triclinic P1 space group. There are four inequivalent La sites. In the first La site, La(1) is bonded in a 4-coordinate geometry to two equivalent As(3), two equivalent As(4), one O(1), one O(2), and two equivalent O(3) atoms. In the second La site, La(2) is bonded in a 4-coordinate geometry to two equivalent As(3), two equivalent As(4), one O(1), one O(2), and two equivalent O(4) atoms. In the third La site, La(3) is bonded in a 4-coordinate geometry to two equivalent As(1), two equivalent As(2), one O(3), one O(4), and two equivalent O(1) atoms. In the fourth La site, La(4) is bonded in a 4-coordinate geometry to two equivalent As(1), two equivalent As(2), one O(3), one O(4), and two equivalent O(2) atoms. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one As(1), one As(2), and two equivalent As(4) atoms to form a mixture of corner and edge-sharing FeAs4 tetrahedra. In the second Fe site, Fe(2) is bonded to one As(3), one As(4), and two equivalent As(2) atoms to form a mixture of corner and edge-sharing FeAs4 tetrahedra. In the third Fe site, Fe(3) is bonded to one As(1), one As(2), and two equivalent As(3) atoms to form a mixture of distorted corner and edge-sharing FeAs4 tetrahedra. In the fourth Fe site, Fe(4) is bonded to one As(3), one As(4), and two equivalent As(1) atoms to form a mixture of distorted corner and edge-sharing FeAs4 tetrahedra. There are four inequivalent As sites. In the first As site, As(1) is bonded in a 8-coordinate geometry to two equivalent La(3), two equivalent La(4), one Fe(1), one Fe(3), and two equivalent Fe(4) atoms. In the second As site, As(2) is bonded in a 8-coordinate geometry to two equivalent La(3), two equivalent La(4), one Fe(1), one Fe(3), and two equivalent Fe(2) atoms. In the third As site, As(3) is bonded in a 8-coordinate geometry to two equivalent La(1), two equivalent La(2), one Fe(2), one Fe(4), and two equivalent Fe(3) atoms. In the fourth As site, As(4) is bonded in a 8-coordinate geometry to two equivalent La(1), two equivalent La(2), one Fe(2), one Fe(4), and two equivalent Fe(1) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded to one La(1), one La(2), and two equivalent La(3) atoms to form a mixture of corner and edge-sharing OLa4 tetrahedra. In the second O site, O(2) is bonded to one La(1), one La(2), and two equivalent La(4) atoms to form a mixture of corner and edge-sharing OLa4 tetrahedra. In the third O site, O(3) is bonded to one La(3), one La(4), and two equivalent La(1) atoms to form a mixture of corner and edge-sharing OLa4 tetrahedra. In the fourth O site, O(4) is bonded to one La(3), one La(4), and two equivalent La(2) atoms to form a mixture of corner and edge-sharing OLa4 tetrahedra. is represented by the CIF file [CIF]
data_LaFeAsO
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.130
_cell_length_b   4.139
_cell_length_c   9.160
_cell_angle_alpha   90.060
_cell_angle_beta   90.412
_cell_angle_gamma   89.974
_symmetry_Int_Tables_number   1
_cell_volume   156.550
_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
  As  As0  1  0.238  0.247  0.670  1.0
  As  As1  1  0.758  0.747  0.330  1.0
  Fe  Fe2  1  0.747  0.254  0.500  1.0
  Fe  Fe3  1  0.257  0.753  0.499  1.0
  La  La4  1  0.252  0.250  0.131  1.0
  La  La5  1  0.748  0.750  0.869  1.0
  O  O6  1  0.750  0.250  1.000  1.0
  O  O7  1  0.250  0.750  0.000  1.0
[/CIF]
.