The crystal structure described by CaFe5As3 crystallizes in the monoclinic P2_1/m space group. Ca(1) is bonded in a 16-coordinate geometry to one Fe(2), three equivalent Fe(1), three equivalent Fe(4), three equivalent Fe(5), two equivalent As(1), two equivalent As(2), and two equivalent As(3) atoms. There are five inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to three equivalent Ca(1), one As(2), and three equivalent As(1) atoms to form distorted FeCa3As4 tetrahedra that share  a cornercorner with one Fe(2)CaAs4 tetrahedra, corners with five equivalent Fe(4)Ca3As4 tetrahedra, corners with seven equivalent Fe(5)Ca3As4 tetrahedra,  an edgeedge with one Fe(2)CaAs4 tetrahedra, edges with two equivalent Fe(1)Ca3As4 tetrahedra, edges with two equivalent Fe(4)Ca3As4 tetrahedra,  a faceface with one Fe(4)Ca3As4 tetrahedra,  a faceface with one Fe(5)Ca3As4 tetrahedra, faces with two equivalent Fe(1)Ca3As4 tetrahedra, and faces with two equivalent Fe(2)CaAs4 tetrahedra. In the second Fe site, Fe(2) is bonded to one Ca(1), one As(1), and three equivalent As(2) atoms to form distorted FeCaAs4 tetrahedra that share  a cornercorner with one Fe(1)Ca3As4 tetrahedra, corners with two equivalent Fe(5)Ca3As4 tetrahedra, corners with two equivalent Fe(2)CaAs4 tetrahedra, corners with four equivalent Fe(4)Ca3As4 tetrahedra,  an edgeedge with one Fe(1)Ca3As4 tetrahedra, edges with two equivalent Fe(5)Ca3As4 tetrahedra, edges with two equivalent Fe(2)CaAs4 tetrahedra, and faces with two equivalent Fe(1)Ca3As4 tetrahedra. In the third Fe site, Fe(3) is bonded in a 5-coordinate geometry to one As(3), two equivalent As(1), and two equivalent As(2) atoms. In the fourth Fe site, Fe(4) is bonded to three equivalent Ca(1), one As(1), and three equivalent As(3) atoms to form distorted FeCa3As4 tetrahedra that share corners with four equivalent Fe(5)Ca3As4 tetrahedra, corners with four equivalent Fe(2)CaAs4 tetrahedra, corners with five equivalent Fe(1)Ca3As4 tetrahedra, edges with two equivalent Fe(1)Ca3As4 tetrahedra, edges with two equivalent Fe(4)Ca3As4 tetrahedra, edges with four equivalent Fe(5)Ca3As4 tetrahedra,  a faceface with one Fe(1)Ca3As4 tetrahedra, faces with two equivalent Fe(4)Ca3As4 tetrahedra, and faces with two equivalent Fe(5)Ca3As4 tetrahedra. In the fifth Fe site, Fe(5) is bonded to three equivalent Ca(1), one As(2), and three equivalent As(3) atoms to form distorted FeCa3As4 tetrahedra that share corners with two equivalent Fe(2)CaAs4 tetrahedra, corners with four equivalent Fe(4)Ca3As4 tetrahedra, corners with seven equivalent Fe(1)Ca3As4 tetrahedra, edges with two equivalent Fe(5)Ca3As4 tetrahedra, edges with two equivalent Fe(2)CaAs4 tetrahedra, edges with four equivalent Fe(4)Ca3As4 tetrahedra,  a faceface with one Fe(1)Ca3As4 tetrahedra, faces with two equivalent Fe(4)Ca3As4 tetrahedra, and faces with two equivalent Fe(5)Ca3As4 tetrahedra. There are three inequivalent As sites. In the first As site, As(1) is bonded in a 9-coordinate geometry to two equivalent Ca(1), one Fe(2), one Fe(4), two equivalent Fe(3), and three equivalent Fe(1) atoms. In the second As site, As(2) is bonded in a 9-coordinate geometry to two equivalent Ca(1), one Fe(1), one Fe(5), two equivalent Fe(3), and three equivalent Fe(2) atoms. In the third As site, As(3) is bonded in a 9-coordinate geometry to two equivalent Ca(1), one Fe(3), three equivalent Fe(4), and three equivalent Fe(5) atoms. is represented by the CIF file [CIF]
data_CaFe5As3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.814
_cell_length_b   7.272
_cell_length_c   9.468
_cell_angle_alpha   78.869
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   257.681
_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
  Ca  Ca0  1  0.250  0.304  0.281  1.0
  Ca  Ca1  1  0.750  0.696  0.719  1.0
  Fe  Fe2  1  0.250  0.618  0.999  1.0
  Fe  Fe3  1  0.750  0.382  0.001  1.0
  Fe  Fe4  1  0.750  0.877  0.995  1.0
  Fe  Fe5  1  0.250  0.123  0.005  1.0
  Fe  Fe6  1  0.250  0.816  0.206  1.0
  Fe  Fe7  1  0.750  0.184  0.794  1.0
  Fe  Fe8  1  0.750  0.577  0.419  1.0
  Fe  Fe9  1  0.250  0.423  0.581  1.0
  Fe  Fe10  1  0.750  0.966  0.420  1.0
  Fe  Fe11  1  0.250  0.034  0.580  1.0
  As  As12  1  0.750  0.601  0.162  1.0
  As  As13  1  0.250  0.399  0.838  1.0
  As  As14  1  0.750  0.072  0.158  1.0
  As  As15  1  0.250  0.928  0.842  1.0
  As  As16  1  0.250  0.756  0.473  1.0
  As  As17  1  0.750  0.244  0.527  1.0
[/CIF]
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The crystal structure described by CaFe5As3 crystallizes in the monoclinic P2_1/m space group. Ca(1) is bonded in a 16-coordinate geometry to one Fe(2), three equivalent Fe(1), three equivalent Fe(4), three equivalent Fe(5), two equivalent As(1), two equivalent As(2), and two equivalent As(3) atoms. There are five inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to three equivalent Ca(1), one As(2), and three equivalent As(1) atoms to form distorted FeCa3As4 tetrahedra that share  a cornercorner with one Fe(2)CaAs4 tetrahedra, corners with five equivalent Fe(4)Ca3As4 tetrahedra, corners with seven equivalent Fe(5)Ca3As4 tetrahedra,  an edgeedge with one Fe(2)CaAs4 tetrahedra, edges with two equivalent Fe(1)Ca3As4 tetrahedra, edges with two equivalent Fe(4)Ca3As4 tetrahedra,  a faceface with one Fe(4)Ca3As4 tetrahedra,  a faceface with one Fe(5)Ca3As4 tetrahedra, faces with two equivalent Fe(1)Ca3As4 tetrahedra, and faces with two equivalent Fe(2)CaAs4 tetrahedra. In the second Fe site, Fe(2) is bonded to one Ca(1), one As(1), and three equivalent As(2) atoms to form distorted FeCaAs4 tetrahedra that share  a cornercorner with one Fe(1)Ca3As4 tetrahedra, corners with two equivalent Fe(5)Ca3As4 tetrahedra, corners with two equivalent Fe(2)CaAs4 tetrahedra, corners with four equivalent Fe(4)Ca3As4 tetrahedra,  an edgeedge with one Fe(1)Ca3As4 tetrahedra, edges with two equivalent Fe(5)Ca3As4 tetrahedra, edges with two equivalent Fe(2)CaAs4 tetrahedra, and faces with two equivalent Fe(1)Ca3As4 tetrahedra. In the third Fe site, Fe(3) is bonded in a 5-coordinate geometry to one As(3), two equivalent As(1), and two equivalent As(2) atoms. In the fourth Fe site, Fe(4) is bonded to three equivalent Ca(1), one As(1), and three equivalent As(3) atoms to form distorted FeCa3As4 tetrahedra that share corners with four equivalent Fe(5)Ca3As4 tetrahedra, corners with four equivalent Fe(2)CaAs4 tetrahedra, corners with five equivalent Fe(1)Ca3As4 tetrahedra, edges with two equivalent Fe(1)Ca3As4 tetrahedra, edges with two equivalent Fe(4)Ca3As4 tetrahedra, edges with four equivalent Fe(5)Ca3As4 tetrahedra,  a faceface with one Fe(1)Ca3As4 tetrahedra, faces with two equivalent Fe(4)Ca3As4 tetrahedra, and faces with two equivalent Fe(5)Ca3As4 tetrahedra. In the fifth Fe site, Fe(5) is bonded to three equivalent Ca(1), one As(2), and three equivalent As(3) atoms to form distorted FeCa3As4 tetrahedra that share corners with two equivalent Fe(2)CaAs4 tetrahedra, corners with four equivalent Fe(4)Ca3As4 tetrahedra, corners with seven equivalent Fe(1)Ca3As4 tetrahedra, edges with two equivalent Fe(5)Ca3As4 tetrahedra, edges with two equivalent Fe(2)CaAs4 tetrahedra, edges with four equivalent Fe(4)Ca3As4 tetrahedra,  a faceface with one Fe(1)Ca3As4 tetrahedra, faces with two equivalent Fe(4)Ca3As4 tetrahedra, and faces with two equivalent Fe(5)Ca3As4 tetrahedra. There are three inequivalent As sites. In the first As site, As(1) is bonded in a 9-coordinate geometry to two equivalent Ca(1), one Fe(2), one Fe(4), two equivalent Fe(3), and three equivalent Fe(1) atoms. In the second As site, As(2) is bonded in a 9-coordinate geometry to two equivalent Ca(1), one Fe(1), one Fe(5), two equivalent Fe(3), and three equivalent Fe(2) atoms. In the third As site, As(3) is bonded in a 9-coordinate geometry to two equivalent Ca(1), one Fe(3), three equivalent Fe(4), and three equivalent Fe(5) atoms. is represented by the CIF file [CIF]
data_CaFe5As3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.814
_cell_length_b   7.272
_cell_length_c   9.468
_cell_angle_alpha   78.869
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   257.681
_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
  Ca  Ca0  1  0.250  0.304  0.281  1.0
  Ca  Ca1  1  0.750  0.696  0.719  1.0
  Fe  Fe2  1  0.250  0.618  0.999  1.0
  Fe  Fe3  1  0.750  0.382  0.001  1.0
  Fe  Fe4  1  0.750  0.877  0.995  1.0
  Fe  Fe5  1  0.250  0.123  0.005  1.0
  Fe  Fe6  1  0.250  0.816  0.206  1.0
  Fe  Fe7  1  0.750  0.184  0.794  1.0
  Fe  Fe8  1  0.750  0.577  0.419  1.0
  Fe  Fe9  1  0.250  0.423  0.581  1.0
  Fe  Fe10  1  0.750  0.966  0.420  1.0
  Fe  Fe11  1  0.250  0.034  0.580  1.0
  As  As12  1  0.750  0.601  0.162  1.0
  As  As13  1  0.250  0.399  0.838  1.0
  As  As14  1  0.750  0.072  0.158  1.0
  As  As15  1  0.250  0.928  0.842  1.0
  As  As16  1  0.250  0.756  0.473  1.0
  As  As17  1  0.750  0.244  0.527  1.0
[/CIF]
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