The structure described by Ca3(PO4)2 crystallizes in the monoclinic C2 space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 4-coordinate geometry to two equivalent O(2) and four equivalent O(4) atoms. In the second Ca site, Ca(2) is bonded to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms to form CaO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and edges with two equivalent Ca(2)O6 octahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form PO4 tetrahedra that share corners with six equivalent Ca(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-52°. In the second P site, P(2) is bonded to two equivalent O(3) and two equivalent O(4) atoms to form PO4 tetrahedra that share corners with six equivalent Ca(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 37-57°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to two equivalent Ca(2) and one P(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Ca(1), one Ca(2), and one P(1) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Ca(2) and one P(2) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to two equivalent Ca(1), two equivalent Ca(2), and one P(2) atom. is represented by the CIF file [CIF]
data_Ca3(PO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.272
_cell_length_b   5.272
_cell_length_c   7.234
_cell_angle_alpha   89.713
_cell_angle_beta   89.713
_cell_angle_gamma   115.559
_symmetry_Int_Tables_number   1
_cell_volume   181.367
_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  0.312  0.688  0.000  1.0
  Ca  Ca1  1  0.987  0.003  0.273  1.0
  Ca  Ca2  1  0.997  0.013  0.727  1.0
  P  P3  1  0.349  0.651  0.500  1.0
  P  P4  1  0.653  0.347  0.000  1.0
  O  O5  1  0.675  0.778  0.506  1.0
  O  O6  1  0.222  0.325  0.494  1.0
  O  O7  1  0.264  0.760  0.319  1.0
  O  O8  1  0.240  0.736  0.681  1.0
  O  O9  1  0.731  0.230  0.829  1.0
  O  O10  1  0.770  0.269  0.171  1.0
  O  O11  1  0.770  0.681  0.992  1.0
  O  O12  1  0.319  0.230  0.008  1.0
[/CIF]
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The structure described by Ca3(PO4)2 crystallizes in the monoclinic C2 space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 4-coordinate geometry to two equivalent O(2) and four equivalent O(4) atoms. In the second Ca site, Ca(2) is bonded to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms to form CaO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and edges with two equivalent Ca(2)O6 octahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form PO4 tetrahedra that share corners with six equivalent Ca(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-52°. In the second P site, P(2) is bonded to two equivalent O(3) and two equivalent O(4) atoms to form PO4 tetrahedra that share corners with six equivalent Ca(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 37-57°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to two equivalent Ca(2) and one P(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Ca(1), one Ca(2), and one P(1) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Ca(2) and one P(2) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to two equivalent Ca(1), two equivalent Ca(2), and one P(2) atom. is represented by the CIF file [CIF]
data_Ca3(PO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.272
_cell_length_b   5.272
_cell_length_c   7.234
_cell_angle_alpha   89.713
_cell_angle_beta   89.713
_cell_angle_gamma   115.559
_symmetry_Int_Tables_number   1
_cell_volume   181.367
_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  0.312  0.688  0.000  1.0
  Ca  Ca1  1  0.987  0.003  0.273  1.0
  Ca  Ca2  1  0.997  0.013  0.727  1.0
  P  P3  1  0.349  0.651  0.500  1.0
  P  P4  1  0.653  0.347  0.000  1.0
  O  O5  1  0.675  0.778  0.506  1.0
  O  O6  1  0.222  0.325  0.494  1.0
  O  O7  1  0.264  0.760  0.319  1.0
  O  O8  1  0.240  0.736  0.681  1.0
  O  O9  1  0.731  0.230  0.829  1.0
  O  O10  1  0.770  0.269  0.171  1.0
  O  O11  1  0.770  0.681  0.992  1.0
  O  O12  1  0.319  0.230  0.008  1.0
[/CIF]
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