The compound described by CrAsO4 crystallizes in the orthorhombic Imma space group. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent O(4) and four equivalent O(2) atoms to form CrO6 octahedra that share corners with four equivalent Cr(2)O6 octahedra, corners with two equivalent As(1)O4 tetrahedra, and corners with four equivalent As(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. In the second Cr site, Cr(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form CrO6 octahedra that share corners with two equivalent Cr(1)O6 octahedra, corners with two equivalent As(1)O4 tetrahedra, corners with two equivalent As(2)O4 tetrahedra,  an edgeedge with one Cr(2)O6 octahedra, and  an edgeedge with one As(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. There are two inequivalent As sites. In the first As site, As(1) is bonded to two equivalent O(1) and two equivalent O(4) atoms to form AsO4 tetrahedra that share corners with two equivalent Cr(1)O6 octahedra and corners with four equivalent Cr(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-55°. In the second As site, As(2) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form AsO4 tetrahedra that share corners with two equivalent Cr(1)O6 octahedra, corners with two equivalent Cr(2)O6 octahedra, and  an edgeedge with one Cr(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-59°. There are four inequivalent O sites. In the first O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Cr(2) and one As(2) atom. In the second O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Cr(1) and one As(1) atom. In the third O site, O(1) is bonded in a trigonal planar geometry to two equivalent Cr(2) and one As(1) atom. In the fourth O site, O(2) is bonded in a trigonal planar geometry to one Cr(1), one Cr(2), and one As(2) atom. is represented by the CIF file [CIF]
data_CrAsO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.503
_cell_length_b   9.125
_cell_length_c   9.125
_cell_angle_alpha   70.946
_cell_angle_beta   69.141
_cell_angle_gamma   69.141
_symmetry_Int_Tables_number   1
_cell_volume   460.302
_cell_formula_units_Z   6
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
  Cr  Cr0  1  0.500  0.000  1.000  1.0
  Cr  Cr1  1  0.000  0.500  0.500  1.0
  Cr  Cr2  1  0.385  0.114  0.614  1.0
  Cr  Cr3  1  0.615  0.386  0.886  1.0
  Cr  Cr4  1  0.385  0.614  0.114  1.0
  Cr  Cr5  1  0.615  0.886  0.386  1.0
  As  As6  1  0.691  0.750  0.750  1.0
  As  As7  1  0.309  0.250  0.250  1.0
  As  As8  1  0.176  0.324  0.824  1.0
  As  As9  1  0.824  0.176  0.676  1.0
  As  As10  1  0.176  0.824  0.324  1.0
  As  As11  1  0.824  0.676  0.176  1.0
  O  O12  1  0.531  0.879  0.621  1.0
  O  O13  1  0.469  0.379  0.121  1.0
  O  O14  1  0.469  0.121  0.379  1.0
  O  O15  1  0.531  0.621  0.879  1.0
  O  O16  1  0.311  0.116  0.846  1.0
  O  O17  1  0.689  0.154  0.884  1.0
  O  O18  1  0.226  0.616  0.346  1.0
  O  O19  1  0.774  0.654  0.384  1.0
  O  O20  1  0.689  0.884  0.154  1.0
  O  O21  1  0.311  0.846  0.116  1.0
  O  O22  1  0.774  0.384  0.654  1.0
  O  O23  1  0.226  0.346  0.616  1.0
  O  O24  1  0.314  0.428  0.855  1.0
  O  O25  1  0.686  0.145  0.572  1.0
  O  O26  1  0.903  0.928  0.355  1.0
  O  O27  1  0.097  0.645  0.072  1.0
  O  O28  1  0.686  0.572  0.145  1.0
  O  O29  1  0.314  0.855  0.428  1.0
  O  O30  1  0.097  0.072  0.645  1.0
  O  O31  1  0.903  0.355  0.928  1.0
  O  O32  1  0.721  0.857  0.857  1.0
  O  O33  1  0.279  0.143  0.143  1.0
  O  O34  1  0.066  0.357  0.357  1.0
  O  O35  1  0.934  0.643  0.643  1.0
[/CIF]
.
The compound described by CrAsO4 crystallizes in the orthorhombic Imma space group. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent O(4) and four equivalent O(2) atoms to form CrO6 octahedra that share corners with four equivalent Cr(2)O6 octahedra, corners with two equivalent As(1)O4 tetrahedra, and corners with four equivalent As(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. In the second Cr site, Cr(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form CrO6 octahedra that share corners with two equivalent Cr(1)O6 octahedra, corners with two equivalent As(1)O4 tetrahedra, corners with two equivalent As(2)O4 tetrahedra,  an edgeedge with one Cr(2)O6 octahedra, and  an edgeedge with one As(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. There are two inequivalent As sites. In the first As site, As(1) is bonded to two equivalent O(1) and two equivalent O(4) atoms to form AsO4 tetrahedra that share corners with two equivalent Cr(1)O6 octahedra and corners with four equivalent Cr(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-55°. In the second As site, As(2) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form AsO4 tetrahedra that share corners with two equivalent Cr(1)O6 octahedra, corners with two equivalent Cr(2)O6 octahedra, and  an edgeedge with one Cr(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-59°. There are four inequivalent O sites. In the first O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Cr(2) and one As(2) atom. In the second O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Cr(1) and one As(1) atom. In the third O site, O(1) is bonded in a trigonal planar geometry to two equivalent Cr(2) and one As(1) atom. In the fourth O site, O(2) is bonded in a trigonal planar geometry to one Cr(1), one Cr(2), and one As(2) atom. is represented by the CIF file [CIF]
data_CrAsO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.503
_cell_length_b   9.125
_cell_length_c   9.125
_cell_angle_alpha   70.946
_cell_angle_beta   69.141
_cell_angle_gamma   69.141
_symmetry_Int_Tables_number   1
_cell_volume   460.302
_cell_formula_units_Z   6
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
  Cr  Cr0  1  0.500  0.000  1.000  1.0
  Cr  Cr1  1  0.000  0.500  0.500  1.0
  Cr  Cr2  1  0.385  0.114  0.614  1.0
  Cr  Cr3  1  0.615  0.386  0.886  1.0
  Cr  Cr4  1  0.385  0.614  0.114  1.0
  Cr  Cr5  1  0.615  0.886  0.386  1.0
  As  As6  1  0.691  0.750  0.750  1.0
  As  As7  1  0.309  0.250  0.250  1.0
  As  As8  1  0.176  0.324  0.824  1.0
  As  As9  1  0.824  0.176  0.676  1.0
  As  As10  1  0.176  0.824  0.324  1.0
  As  As11  1  0.824  0.676  0.176  1.0
  O  O12  1  0.531  0.879  0.621  1.0
  O  O13  1  0.469  0.379  0.121  1.0
  O  O14  1  0.469  0.121  0.379  1.0
  O  O15  1  0.531  0.621  0.879  1.0
  O  O16  1  0.311  0.116  0.846  1.0
  O  O17  1  0.689  0.154  0.884  1.0
  O  O18  1  0.226  0.616  0.346  1.0
  O  O19  1  0.774  0.654  0.384  1.0
  O  O20  1  0.689  0.884  0.154  1.0
  O  O21  1  0.311  0.846  0.116  1.0
  O  O22  1  0.774  0.384  0.654  1.0
  O  O23  1  0.226  0.346  0.616  1.0
  O  O24  1  0.314  0.428  0.855  1.0
  O  O25  1  0.686  0.145  0.572  1.0
  O  O26  1  0.903  0.928  0.355  1.0
  O  O27  1  0.097  0.645  0.072  1.0
  O  O28  1  0.686  0.572  0.145  1.0
  O  O29  1  0.314  0.855  0.428  1.0
  O  O30  1  0.097  0.072  0.645  1.0
  O  O31  1  0.903  0.355  0.928  1.0
  O  O32  1  0.721  0.857  0.857  1.0
  O  O33  1  0.279  0.143  0.143  1.0
  O  O34  1  0.066  0.357  0.357  1.0
  O  O35  1  0.934  0.643  0.643  1.0
[/CIF]
.