The material described by Co2As crystallizes in the hexagonal P-62m space group. There are six inequivalent Co sites. In the first Co site, Co(1) is bonded in a 5-coordinate geometry to one As(2) and four equivalent As(3) atoms. In the second Co site, Co(2) is bonded in a 5-coordinate geometry to one As(1) and four equivalent As(3) atoms. In the third Co site, Co(3) is bonded in a 5-coordinate geometry to one As(3), two equivalent As(2), and two equivalent As(4) atoms. In the fourth Co site, Co(4) is bonded to two equivalent As(1) and two equivalent As(3) atoms to form a mixture of distorted corner and edge-sharing CoAs4 tetrahedra. In the fifth Co site, Co(5) is bonded to two equivalent As(2) and two equivalent As(3) atoms to form a mixture of distorted corner and edge-sharing CoAs4 tetrahedra. In the sixth Co site, Co(6) is bonded to one As(2), one As(4), and two equivalent As(3) atoms to form a mixture of distorted corner and edge-sharing CoAs4 tetrahedra. There are four inequivalent As sites. In the first As site, As(4) is bonded in a 9-coordinate geometry to three equivalent Co(6) and six equivalent Co(3) atoms. In the second As site, As(1) is bonded in a 9-coordinate geometry to three equivalent Co(2) and six equivalent Co(4) atoms. In the third As site, As(2) is bonded in a 9-coordinate geometry to one Co(1), two equivalent Co(5), two equivalent Co(6), and four equivalent Co(3) atoms. In the fourth As site, As(3) is bonded in a 9-coordinate geometry to one Co(3), one Co(4), one Co(5), two equivalent Co(1), two equivalent Co(2), and two equivalent Co(6) atoms. is represented by the CIF file [CIF]
data_Co2As
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   11.898
_cell_length_b   11.898
_cell_length_c   3.582
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   439.127
_cell_formula_units_Z   12
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
  Co  Co0  1  0.312  0.000  0.000  1.0
  Co  Co1  1  0.688  0.688  0.000  1.0
  Co  Co2  1  0.000  0.312  0.000  1.0
  Co  Co3  1  0.797  0.000  0.000  1.0
  Co  Co4  1  0.203  0.203  0.000  1.0
  Co  Co5  1  0.000  0.797  0.000  1.0
  Co  Co6  1  0.172  0.544  0.500  1.0
  Co  Co7  1  0.371  0.828  0.500  1.0
  Co  Co8  1  0.456  0.629  0.500  1.0
  Co  Co9  1  0.629  0.456  0.500  1.0
  Co  Co10  1  0.828  0.371  0.500  1.0
  Co  Co11  1  0.544  0.172  0.500  1.0
  Co  Co12  1  0.128  0.000  0.500  1.0
  Co  Co13  1  0.872  0.872  0.500  1.0
  Co  Co14  1  0.000  0.128  0.500  1.0
  Co  Co15  1  0.628  0.000  0.500  1.0
  Co  Co16  1  0.372  0.372  0.500  1.0
  Co  Co17  1  0.000  0.628  0.500  1.0
  Co  Co18  1  0.175  0.719  0.000  1.0
  Co  Co19  1  0.543  0.825  0.000  1.0
  Co  Co20  1  0.281  0.457  0.000  1.0
  Co  Co21  1  0.457  0.281  0.000  1.0
  Co  Co22  1  0.825  0.543  0.000  1.0
  Co  Co23  1  0.719  0.175  0.000  1.0
  As  As24  1  0.000  0.000  0.000  1.0
  As  As25  1  0.503  0.000  0.000  1.0
  As  As26  1  0.497  0.497  0.000  1.0
  As  As27  1  0.000  0.503  0.000  1.0
  As  As28  1  0.336  0.158  0.500  1.0
  As  As29  1  0.822  0.664  0.500  1.0
  As  As30  1  0.842  0.178  0.500  1.0
  As  As31  1  0.178  0.842  0.500  1.0
  As  As32  1  0.664  0.822  0.500  1.0
  As  As33  1  0.158  0.336  0.500  1.0
  As  As34  1  0.333  0.667  0.000  1.0
  As  As35  1  0.667  0.333  0.000  1.0
[/CIF]
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The material described by Co2As crystallizes in the hexagonal P-62m space group. There are six inequivalent Co sites. In the first Co site, Co(1) is bonded in a 5-coordinate geometry to one As(2) and four equivalent As(3) atoms. In the second Co site, Co(2) is bonded in a 5-coordinate geometry to one As(1) and four equivalent As(3) atoms. In the third Co site, Co(3) is bonded in a 5-coordinate geometry to one As(3), two equivalent As(2), and two equivalent As(4) atoms. In the fourth Co site, Co(4) is bonded to two equivalent As(1) and two equivalent As(3) atoms to form a mixture of distorted corner and edge-sharing CoAs4 tetrahedra. In the fifth Co site, Co(5) is bonded to two equivalent As(2) and two equivalent As(3) atoms to form a mixture of distorted corner and edge-sharing CoAs4 tetrahedra. In the sixth Co site, Co(6) is bonded to one As(2), one As(4), and two equivalent As(3) atoms to form a mixture of distorted corner and edge-sharing CoAs4 tetrahedra. There are four inequivalent As sites. In the first As site, As(4) is bonded in a 9-coordinate geometry to three equivalent Co(6) and six equivalent Co(3) atoms. In the second As site, As(1) is bonded in a 9-coordinate geometry to three equivalent Co(2) and six equivalent Co(4) atoms. In the third As site, As(2) is bonded in a 9-coordinate geometry to one Co(1), two equivalent Co(5), two equivalent Co(6), and four equivalent Co(3) atoms. In the fourth As site, As(3) is bonded in a 9-coordinate geometry to one Co(3), one Co(4), one Co(5), two equivalent Co(1), two equivalent Co(2), and two equivalent Co(6) atoms. is represented by the CIF file [CIF]
data_Co2As
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   11.898
_cell_length_b   11.898
_cell_length_c   3.582
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   439.127
_cell_formula_units_Z   12
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
  Co  Co0  1  0.312  0.000  0.000  1.0
  Co  Co1  1  0.688  0.688  0.000  1.0
  Co  Co2  1  0.000  0.312  0.000  1.0
  Co  Co3  1  0.797  0.000  0.000  1.0
  Co  Co4  1  0.203  0.203  0.000  1.0
  Co  Co5  1  0.000  0.797  0.000  1.0
  Co  Co6  1  0.172  0.544  0.500  1.0
  Co  Co7  1  0.371  0.828  0.500  1.0
  Co  Co8  1  0.456  0.629  0.500  1.0
  Co  Co9  1  0.629  0.456  0.500  1.0
  Co  Co10  1  0.828  0.371  0.500  1.0
  Co  Co11  1  0.544  0.172  0.500  1.0
  Co  Co12  1  0.128  0.000  0.500  1.0
  Co  Co13  1  0.872  0.872  0.500  1.0
  Co  Co14  1  0.000  0.128  0.500  1.0
  Co  Co15  1  0.628  0.000  0.500  1.0
  Co  Co16  1  0.372  0.372  0.500  1.0
  Co  Co17  1  0.000  0.628  0.500  1.0
  Co  Co18  1  0.175  0.719  0.000  1.0
  Co  Co19  1  0.543  0.825  0.000  1.0
  Co  Co20  1  0.281  0.457  0.000  1.0
  Co  Co21  1  0.457  0.281  0.000  1.0
  Co  Co22  1  0.825  0.543  0.000  1.0
  Co  Co23  1  0.719  0.175  0.000  1.0
  As  As24  1  0.000  0.000  0.000  1.0
  As  As25  1  0.503  0.000  0.000  1.0
  As  As26  1  0.497  0.497  0.000  1.0
  As  As27  1  0.000  0.503  0.000  1.0
  As  As28  1  0.336  0.158  0.500  1.0
  As  As29  1  0.822  0.664  0.500  1.0
  As  As30  1  0.842  0.178  0.500  1.0
  As  As31  1  0.178  0.842  0.500  1.0
  As  As32  1  0.664  0.822  0.500  1.0
  As  As33  1  0.158  0.336  0.500  1.0
  As  As34  1  0.333  0.667  0.000  1.0
  As  As35  1  0.667  0.333  0.000  1.0
[/CIF]
.