The crystal structure described by CaAsO4 crystallizes in the triclinic P-1 space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to one O(1), one O(4), one O(6), one O(8), and two equivalent O(2) atoms to form distorted CaO6 octahedra that share corners with two equivalent As(2)O4 tetrahedra, corners with four equivalent As(1)O4 tetrahedra, and  an edgeedge with one Ca(1)O6 octahedra. In the second Ca site, Ca(2) is bonded in a 8-coordinate geometry to one O(2), one O(4), one O(5), one O(6), one O(7), one O(8), and two equivalent O(3) atoms. There are two inequivalent As sites. In the first As site, As(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form AsO4 tetrahedra that share corners with four equivalent Ca(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 36-63°. In the second As site, As(2) is bonded to one O(5), one O(6), one O(7), and one O(8) atom to form AsO4 tetrahedra that share corners with two equivalent Ca(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-67°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Ca(1) and one As(1) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Ca(2), two equivalent Ca(1), and one As(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to two equivalent Ca(2) and one As(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Ca(1), one Ca(2), and one As(1) atom. In the fifth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one Ca(2) and one As(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Ca(1), one Ca(2), and one As(2) atom. In the seventh O site, O(7) is bonded in a 2-coordinate geometry to one Ca(2) and one As(2) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Ca(1), one Ca(2), and one As(2) atom. is represented by the CIF file [CIF]
data_CaAsO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.015
_cell_length_b   7.030
_cell_length_c   7.278
_cell_angle_alpha   76.130
_cell_angle_beta   81.358
_cell_angle_gamma   85.561
_symmetry_Int_Tables_number   1
_cell_volume   344.180
_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
  Ca  Ca0  1  0.568  0.684  0.268  1.0
  Ca  Ca1  1  0.432  0.316  0.732  1.0
  Ca  Ca2  1  0.156  0.812  0.653  1.0
  Ca  Ca3  1  0.844  0.188  0.347  1.0
  As  As4  1  0.622  0.797  0.711  1.0
  As  As5  1  0.378  0.203  0.289  1.0
  As  As6  1  0.065  0.710  0.192  1.0
  As  As7  1  0.935  0.290  0.808  1.0
  O  O8  1  0.665  0.687  0.942  1.0
  O  O9  1  0.335  0.313  0.058  1.0
  O  O10  1  0.502  0.649  0.614  1.0
  O  O11  1  0.498  0.351  0.386  1.0
  O  O12  1  0.834  0.871  0.572  1.0
  O  O13  1  0.166  0.129  0.428  1.0
  O  O14  1  0.457  0.986  0.730  1.0
  O  O15  1  0.543  0.014  0.270  1.0
  O  O16  1  0.198  0.667  0.985  1.0
  O  O17  1  0.802  0.333  0.015  1.0
  O  O18  1  0.891  0.542  0.286  1.0
  O  O19  1  0.109  0.458  0.714  1.0
  O  O20  1  0.934  0.935  0.144  1.0
  O  O21  1  0.066  0.065  0.856  1.0
  O  O22  1  0.224  0.716  0.346  1.0
  O  O23  1  0.776  0.284  0.654  1.0
[/CIF]
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The crystal structure described by CaAsO4 crystallizes in the triclinic P-1 space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to one O(1), one O(4), one O(6), one O(8), and two equivalent O(2) atoms to form distorted CaO6 octahedra that share corners with two equivalent As(2)O4 tetrahedra, corners with four equivalent As(1)O4 tetrahedra, and  an edgeedge with one Ca(1)O6 octahedra. In the second Ca site, Ca(2) is bonded in a 8-coordinate geometry to one O(2), one O(4), one O(5), one O(6), one O(7), one O(8), and two equivalent O(3) atoms. There are two inequivalent As sites. In the first As site, As(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form AsO4 tetrahedra that share corners with four equivalent Ca(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 36-63°. In the second As site, As(2) is bonded to one O(5), one O(6), one O(7), and one O(8) atom to form AsO4 tetrahedra that share corners with two equivalent Ca(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-67°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Ca(1) and one As(1) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Ca(2), two equivalent Ca(1), and one As(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to two equivalent Ca(2) and one As(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Ca(1), one Ca(2), and one As(1) atom. In the fifth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one Ca(2) and one As(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Ca(1), one Ca(2), and one As(2) atom. In the seventh O site, O(7) is bonded in a 2-coordinate geometry to one Ca(2) and one As(2) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Ca(1), one Ca(2), and one As(2) atom. is represented by the CIF file [CIF]
data_CaAsO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.015
_cell_length_b   7.030
_cell_length_c   7.278
_cell_angle_alpha   76.130
_cell_angle_beta   81.358
_cell_angle_gamma   85.561
_symmetry_Int_Tables_number   1
_cell_volume   344.180
_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
  Ca  Ca0  1  0.568  0.684  0.268  1.0
  Ca  Ca1  1  0.432  0.316  0.732  1.0
  Ca  Ca2  1  0.156  0.812  0.653  1.0
  Ca  Ca3  1  0.844  0.188  0.347  1.0
  As  As4  1  0.622  0.797  0.711  1.0
  As  As5  1  0.378  0.203  0.289  1.0
  As  As6  1  0.065  0.710  0.192  1.0
  As  As7  1  0.935  0.290  0.808  1.0
  O  O8  1  0.665  0.687  0.942  1.0
  O  O9  1  0.335  0.313  0.058  1.0
  O  O10  1  0.502  0.649  0.614  1.0
  O  O11  1  0.498  0.351  0.386  1.0
  O  O12  1  0.834  0.871  0.572  1.0
  O  O13  1  0.166  0.129  0.428  1.0
  O  O14  1  0.457  0.986  0.730  1.0
  O  O15  1  0.543  0.014  0.270  1.0
  O  O16  1  0.198  0.667  0.985  1.0
  O  O17  1  0.802  0.333  0.015  1.0
  O  O18  1  0.891  0.542  0.286  1.0
  O  O19  1  0.109  0.458  0.714  1.0
  O  O20  1  0.934  0.935  0.144  1.0
  O  O21  1  0.066  0.065  0.856  1.0
  O  O22  1  0.224  0.716  0.346  1.0
  O  O23  1  0.776  0.284  0.654  1.0
[/CIF]
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