The crystal structure described by Ca5P8 crystallizes in the monoclinic C2/m space group. There are three inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to two equivalent P(1) and four equivalent P(2) atoms to form CaP6 octahedra that share corners with four equivalent Ca(3)P6 octahedra, corners with two equivalent P(3)P4 tetrahedra, edges with four equivalent Ca(3)P6 octahedra, edges with six equivalent Ca(2)P6 octahedra, and edges with two equivalent P(3)P4 tetrahedra. The corner-sharing octahedral tilt angles are 9°. In the second Ca site, Ca(2) is bonded to two equivalent P(1) and four equivalent P(2) atoms to form CaP6 octahedra that share corners with four equivalent Ca(3)P6 octahedra, corners with two equivalent P(3)P4 tetrahedra, edges with three equivalent Ca(1)P6 octahedra, edges with three equivalent Ca(2)P6 octahedra, edges with four equivalent Ca(3)P6 octahedra, and edges with two equivalent P(3)P4 tetrahedra. The corner-sharing octahedral tilt angles range from 9-10°. In the third Ca site, Ca(3) is bonded to two equivalent P(1) and four equivalent P(2) atoms to form CaP6 octahedra that share corners with two equivalent Ca(1)P6 octahedra, corners with four equivalent Ca(2)P6 octahedra, corners with six equivalent P(3)P4 tetrahedra, edges with two equivalent Ca(1)P6 octahedra, edges with three equivalent Ca(3)P6 octahedra, and edges with four equivalent Ca(2)P6 octahedra. The corner-sharing octahedral tilt angles range from 9-10°. There are three inequivalent P sites. In the first P site, P(1) is bonded to one Ca(1), two equivalent Ca(2), two equivalent Ca(3), and one P(3) atom to form PCa5P octahedra that share  a cornercorner with one P(1)Ca5P octahedra, corners with six equivalent P(2)Ca5P octahedra,  a cornercorner with one P(3)P4 tetrahedra, edges with two equivalent P(1)Ca5P octahedra, and edges with eight equivalent P(2)Ca5P octahedra. The corner-sharing octahedral tilt angles range from 0-94°. In the second P site, P(2) is bonded to one Ca(1), two equivalent Ca(2), two equivalent Ca(3), and one P(3) atom to form PCa5P octahedra that share corners with three equivalent P(1)Ca5P octahedra, corners with four equivalent P(2)Ca5P octahedra,  a cornercorner with one P(3)P4 tetrahedra, edges with four equivalent P(1)Ca5P octahedra, and edges with six equivalent P(2)Ca5P octahedra. The corner-sharing octahedral tilt angles range from 0-95°. In the third P site, P(3) is bonded to one P(1), one P(3), and two equivalent P(2) atoms to form distorted PP4 tetrahedra that share  a cornercorner with one Ca(1)P6 octahedra,  a cornercorner with one P(1)Ca5P octahedra, corners with two equivalent Ca(2)P6 octahedra, corners with two equivalent P(2)Ca5P octahedra, corners with six equivalent Ca(3)P6 octahedra,  an edgeedge with one Ca(1)P6 octahedra, and edges with two equivalent Ca(2)P6 octahedra. The corner-sharing octahedral tilt angles range from 21-76°. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ca5P8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.882
_cell_length_b   6.882
_cell_length_c   7.496
_cell_angle_alpha   99.002
_cell_angle_beta   99.002
_cell_angle_gamma   119.686
_symmetry_Int_Tables_number   1
_cell_volume   293.085
_cell_formula_units_Z   1
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  0.500  0.500  0.500  1.0
  Ca  Ca1  1  0.825  0.175  0.500  1.0
  Ca  Ca2  1  0.175  0.825  0.500  1.0
  Ca  Ca3  1  0.335  0.665  0.000  1.0
  Ca  Ca4  1  0.665  0.335  0.000  1.0
  P  P5  1  0.221  0.221  0.758  1.0
  P  P6  1  0.779  0.779  0.242  1.0
  P  P7  1  0.617  0.921  0.760  1.0
  P  P8  1  0.079  0.383  0.240  1.0
  P  P9  1  0.383  0.079  0.240  1.0
  P  P10  1  0.921  0.617  0.760  1.0
  P  P11  1  0.948  0.948  0.837  1.0
  P  P12  1  0.052  0.052  0.163  1.0
[/CIF]
.
The crystal structure described by Ca5P8 crystallizes in the monoclinic C2/m space group. There are three inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to two equivalent P(1) and four equivalent P(2) atoms to form CaP6 octahedra that share corners with four equivalent Ca(3)P6 octahedra, corners with two equivalent P(3)P4 tetrahedra, edges with four equivalent Ca(3)P6 octahedra, edges with six equivalent Ca(2)P6 octahedra, and edges with two equivalent P(3)P4 tetrahedra. The corner-sharing octahedral tilt angles are 9°. In the second Ca site, Ca(2) is bonded to two equivalent P(1) and four equivalent P(2) atoms to form CaP6 octahedra that share corners with four equivalent Ca(3)P6 octahedra, corners with two equivalent P(3)P4 tetrahedra, edges with three equivalent Ca(1)P6 octahedra, edges with three equivalent Ca(2)P6 octahedra, edges with four equivalent Ca(3)P6 octahedra, and edges with two equivalent P(3)P4 tetrahedra. The corner-sharing octahedral tilt angles range from 9-10°. In the third Ca site, Ca(3) is bonded to two equivalent P(1) and four equivalent P(2) atoms to form CaP6 octahedra that share corners with two equivalent Ca(1)P6 octahedra, corners with four equivalent Ca(2)P6 octahedra, corners with six equivalent P(3)P4 tetrahedra, edges with two equivalent Ca(1)P6 octahedra, edges with three equivalent Ca(3)P6 octahedra, and edges with four equivalent Ca(2)P6 octahedra. The corner-sharing octahedral tilt angles range from 9-10°. There are three inequivalent P sites. In the first P site, P(1) is bonded to one Ca(1), two equivalent Ca(2), two equivalent Ca(3), and one P(3) atom to form PCa5P octahedra that share  a cornercorner with one P(1)Ca5P octahedra, corners with six equivalent P(2)Ca5P octahedra,  a cornercorner with one P(3)P4 tetrahedra, edges with two equivalent P(1)Ca5P octahedra, and edges with eight equivalent P(2)Ca5P octahedra. The corner-sharing octahedral tilt angles range from 0-94°. In the second P site, P(2) is bonded to one Ca(1), two equivalent Ca(2), two equivalent Ca(3), and one P(3) atom to form PCa5P octahedra that share corners with three equivalent P(1)Ca5P octahedra, corners with four equivalent P(2)Ca5P octahedra,  a cornercorner with one P(3)P4 tetrahedra, edges with four equivalent P(1)Ca5P octahedra, and edges with six equivalent P(2)Ca5P octahedra. The corner-sharing octahedral tilt angles range from 0-95°. In the third P site, P(3) is bonded to one P(1), one P(3), and two equivalent P(2) atoms to form distorted PP4 tetrahedra that share  a cornercorner with one Ca(1)P6 octahedra,  a cornercorner with one P(1)Ca5P octahedra, corners with two equivalent Ca(2)P6 octahedra, corners with two equivalent P(2)Ca5P octahedra, corners with six equivalent Ca(3)P6 octahedra,  an edgeedge with one Ca(1)P6 octahedra, and edges with two equivalent Ca(2)P6 octahedra. The corner-sharing octahedral tilt angles range from 21-76°. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ca5P8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.882
_cell_length_b   6.882
_cell_length_c   7.496
_cell_angle_alpha   99.002
_cell_angle_beta   99.002
_cell_angle_gamma   119.686
_symmetry_Int_Tables_number   1
_cell_volume   293.085
_cell_formula_units_Z   1
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  0.500  0.500  0.500  1.0
  Ca  Ca1  1  0.825  0.175  0.500  1.0
  Ca  Ca2  1  0.175  0.825  0.500  1.0
  Ca  Ca3  1  0.335  0.665  0.000  1.0
  Ca  Ca4  1  0.665  0.335  0.000  1.0
  P  P5  1  0.221  0.221  0.758  1.0
  P  P6  1  0.779  0.779  0.242  1.0
  P  P7  1  0.617  0.921  0.760  1.0
  P  P8  1  0.079  0.383  0.240  1.0
  P  P9  1  0.383  0.079  0.240  1.0
  P  P10  1  0.921  0.617  0.760  1.0
  P  P11  1  0.948  0.948  0.837  1.0
  P  P12  1  0.052  0.052  0.163  1.0
[/CIF]
.