The compound described by Fe2Co(AsO7)2 crystallizes in the monoclinic P2_1/c space group. Fe(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(5) atoms to form FeO6 octahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with four equivalent As(1)O4 tetrahedra, and  an edgeedge with one Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles are 48°. Co(1) is bonded to two equivalent O(3), two equivalent O(6), and two equivalent O(7) atoms to form CoO6 octahedra that share corners with two equivalent As(1)O4 tetrahedra. 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  a cornercorner with one Co(1)O6 octahedra and corners with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 53-64°. There are seven inequivalent O sites. In the first O site, O(7) is bonded in a 2-coordinate geometry to one Co(1) and one O(6) atom. In the second O site, O(1) is bonded in a trigonal planar geometry to two equivalent Fe(1) and one As(1) atom. In the third O site, O(2) is bonded in a bent 120 degrees geometry to one Fe(1) and one As(1) atom. In the fourth O site, O(3) is bonded in a bent 120 degrees geometry to one Co(1) and one As(1) atom. In the fifth O site, O(4) is bonded in a bent 120 degrees geometry to one Fe(1) and one As(1) atom. In the sixth O site, O(5) is bonded in a bent 120 degrees geometry to two equivalent Fe(1) atoms. In the seventh O site, O(6) is bonded in a 2-coordinate geometry to one Co(1) and one O(7) atom. is represented by the CIF card [CIF]
data_Fe2Co(AsO7)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.691
_cell_length_b   5.597
_cell_length_c   9.661
_cell_angle_alpha   83.753
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   520.935
_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
  Fe  Fe0  1  0.645  0.153  0.450  1.0
  Fe  Fe1  1  0.145  0.347  0.550  1.0
  Fe  Fe2  1  0.355  0.847  0.550  1.0
  Fe  Fe3  1  0.855  0.653  0.450  1.0
  Co  Co4  1  0.500  0.500  0.000  1.0
  Co  Co5  1  0.000  0.000  0.000  1.0
  As  As6  1  0.931  0.163  0.291  1.0
  As  As7  1  0.431  0.337  0.709  1.0
  As  As8  1  0.069  0.837  0.709  1.0
  As  As9  1  0.569  0.663  0.291  1.0
  O  O10  1  0.993  0.387  0.387  1.0
  O  O11  1  0.493  0.113  0.613  1.0
  O  O12  1  0.007  0.613  0.613  1.0
  O  O13  1  0.507  0.887  0.387  1.0
  O  O14  1  0.985  0.877  0.350  1.0
  O  O15  1  0.485  0.623  0.650  1.0
  O  O16  1  0.015  0.123  0.650  1.0
  O  O17  1  0.515  0.377  0.350  1.0
  O  O18  1  0.004  0.229  0.127  1.0
  O  O19  1  0.504  0.271  0.873  1.0
  O  O20  1  0.996  0.771  0.873  1.0
  O  O21  1  0.496  0.729  0.127  1.0
  O  O22  1  0.755  0.186  0.274  1.0
  O  O23  1  0.255  0.314  0.726  1.0
  O  O24  1  0.245  0.814  0.726  1.0
  O  O25  1  0.745  0.686  0.274  1.0
  O  O26  1  0.737  0.420  0.527  1.0
  O  O27  1  0.237  0.080  0.473  1.0
  O  O28  1  0.263  0.580  0.473  1.0
  O  O29  1  0.763  0.920  0.527  1.0
  O  O30  1  0.353  0.335  0.101  1.0
  O  O31  1  0.853  0.165  0.899  1.0
  O  O32  1  0.647  0.665  0.899  1.0
  O  O33  1  0.147  0.835  0.101  1.0
  O  O34  1  0.697  0.514  0.997  1.0
  O  O35  1  0.197  0.986  0.003  1.0
  O  O36  1  0.303  0.486  0.003  1.0
  O  O37  1  0.803  0.014  0.997  1.0
[/CIF]
.
The compound described by Fe2Co(AsO7)2 crystallizes in the monoclinic P2_1/c space group. Fe(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(5) atoms to form FeO6 octahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with four equivalent As(1)O4 tetrahedra, and  an edgeedge with one Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles are 48°. Co(1) is bonded to two equivalent O(3), two equivalent O(6), and two equivalent O(7) atoms to form CoO6 octahedra that share corners with two equivalent As(1)O4 tetrahedra. 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  a cornercorner with one Co(1)O6 octahedra and corners with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 53-64°. There are seven inequivalent O sites. In the first O site, O(7) is bonded in a 2-coordinate geometry to one Co(1) and one O(6) atom. In the second O site, O(1) is bonded in a trigonal planar geometry to two equivalent Fe(1) and one As(1) atom. In the third O site, O(2) is bonded in a bent 120 degrees geometry to one Fe(1) and one As(1) atom. In the fourth O site, O(3) is bonded in a bent 120 degrees geometry to one Co(1) and one As(1) atom. In the fifth O site, O(4) is bonded in a bent 120 degrees geometry to one Fe(1) and one As(1) atom. In the sixth O site, O(5) is bonded in a bent 120 degrees geometry to two equivalent Fe(1) atoms. In the seventh O site, O(6) is bonded in a 2-coordinate geometry to one Co(1) and one O(7) atom. is represented by the CIF card [CIF]
data_Fe2Co(AsO7)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.691
_cell_length_b   5.597
_cell_length_c   9.661
_cell_angle_alpha   83.753
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   520.935
_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
  Fe  Fe0  1  0.645  0.153  0.450  1.0
  Fe  Fe1  1  0.145  0.347  0.550  1.0
  Fe  Fe2  1  0.355  0.847  0.550  1.0
  Fe  Fe3  1  0.855  0.653  0.450  1.0
  Co  Co4  1  0.500  0.500  0.000  1.0
  Co  Co5  1  0.000  0.000  0.000  1.0
  As  As6  1  0.931  0.163  0.291  1.0
  As  As7  1  0.431  0.337  0.709  1.0
  As  As8  1  0.069  0.837  0.709  1.0
  As  As9  1  0.569  0.663  0.291  1.0
  O  O10  1  0.993  0.387  0.387  1.0
  O  O11  1  0.493  0.113  0.613  1.0
  O  O12  1  0.007  0.613  0.613  1.0
  O  O13  1  0.507  0.887  0.387  1.0
  O  O14  1  0.985  0.877  0.350  1.0
  O  O15  1  0.485  0.623  0.650  1.0
  O  O16  1  0.015  0.123  0.650  1.0
  O  O17  1  0.515  0.377  0.350  1.0
  O  O18  1  0.004  0.229  0.127  1.0
  O  O19  1  0.504  0.271  0.873  1.0
  O  O20  1  0.996  0.771  0.873  1.0
  O  O21  1  0.496  0.729  0.127  1.0
  O  O22  1  0.755  0.186  0.274  1.0
  O  O23  1  0.255  0.314  0.726  1.0
  O  O24  1  0.245  0.814  0.726  1.0
  O  O25  1  0.745  0.686  0.274  1.0
  O  O26  1  0.737  0.420  0.527  1.0
  O  O27  1  0.237  0.080  0.473  1.0
  O  O28  1  0.263  0.580  0.473  1.0
  O  O29  1  0.763  0.920  0.527  1.0
  O  O30  1  0.353  0.335  0.101  1.0
  O  O31  1  0.853  0.165  0.899  1.0
  O  O32  1  0.647  0.665  0.899  1.0
  O  O33  1  0.147  0.835  0.101  1.0
  O  O34  1  0.697  0.514  0.997  1.0
  O  O35  1  0.197  0.986  0.003  1.0
  O  O36  1  0.303  0.486  0.003  1.0
  O  O37  1  0.803  0.014  0.997  1.0
[/CIF]
.