The material described by Ca2AlP2O9 crystallizes in the monoclinic P2_1/m space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to one O(2), one O(5), two equivalent O(1), and two equivalent O(4) atoms to form distorted CaO6 octahedra that share corners with two equivalent Al(1)O6 octahedra, corners with three equivalent P(1)O4 tetrahedra, and corners with three equivalent P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 61°. In the second Ca site, Ca(2) is bonded in a 6-coordinate geometry to one O(3), one O(7), and four equivalent O(4) atoms. Al(1) is bonded to two equivalent O(1), two equivalent O(6), and two equivalent O(7) atoms to form AlO6 octahedra that share corners with two equivalent Ca(1)O6 octahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, and edges with two equivalent Al(1)O6 octahedra. The corner-sharing octahedral tilt angles are 61°. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(5), one O(6), and two equivalent O(4) atoms to form PO4 tetrahedra that share corners with two equivalent Al(1)O6 octahedra and corners with three equivalent Ca(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-62°. In the second P site, P(2) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form PO4 tetrahedra that share corners with two equivalent Al(1)O6 octahedra and corners with three equivalent Ca(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-65°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Ca(1), one Al(1), and one P(2) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Ca(1) and one P(2) atom. In the third O site, O(3) is bonded in a linear geometry to one Ca(2) and one P(2) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Ca(1), two equivalent Ca(2), and one P(1) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one Ca(1) and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted T-shaped geometry to two equivalent Al(1) and one P(1) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Ca(2) and two equivalent Al(1) atoms. is represented by the CIF card [CIF]
data_Ca2AlP2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.671
_cell_length_b   7.651
_cell_length_c   8.316
_cell_angle_alpha   66.969
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   332.029
_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  0.750  0.795  0.247  1.0
  Ca  Ca1  1  0.250  0.205  0.753  1.0
  Ca  Ca2  1  0.750  0.177  0.414  1.0
  Ca  Ca3  1  0.250  0.823  0.586  1.0
  Al  Al4  1  0.500  0.500  0.000  1.0
  Al  Al5  1  0.000  0.500  0.000  1.0
  P  P6  1  0.250  0.077  0.184  1.0
  P  P7  1  0.750  0.923  0.816  1.0
  P  P8  1  0.250  0.500  0.333  1.0
  P  P9  1  0.750  0.500  0.667  1.0
  O  O10  1  0.527  0.446  0.792  1.0
  O  O11  1  0.027  0.554  0.208  1.0
  O  O12  1  0.473  0.554  0.208  1.0
  O  O13  1  0.973  0.446  0.792  1.0
  O  O14  1  0.250  0.287  0.447  1.0
  O  O15  1  0.750  0.713  0.553  1.0
  O  O16  1  0.250  0.620  0.442  1.0
  O  O17  1  0.750  0.380  0.558  1.0
  O  O18  1  0.029  0.013  0.304  1.0
  O  O19  1  0.529  0.987  0.696  1.0
  O  O20  1  0.971  0.987  0.696  1.0
  O  O21  1  0.471  0.013  0.304  1.0
  O  O22  1  0.250  0.995  0.044  1.0
  O  O23  1  0.750  0.005  0.956  1.0
  O  O24  1  0.250  0.304  0.087  1.0
  O  O25  1  0.750  0.696  0.913  1.0
  O  O26  1  0.250  0.650  0.892  1.0
  O  O27  1  0.750  0.350  0.108  1.0
[/CIF]
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The material described by Ca2AlP2O9 crystallizes in the monoclinic P2_1/m space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to one O(2), one O(5), two equivalent O(1), and two equivalent O(4) atoms to form distorted CaO6 octahedra that share corners with two equivalent Al(1)O6 octahedra, corners with three equivalent P(1)O4 tetrahedra, and corners with three equivalent P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 61°. In the second Ca site, Ca(2) is bonded in a 6-coordinate geometry to one O(3), one O(7), and four equivalent O(4) atoms. Al(1) is bonded to two equivalent O(1), two equivalent O(6), and two equivalent O(7) atoms to form AlO6 octahedra that share corners with two equivalent Ca(1)O6 octahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, and edges with two equivalent Al(1)O6 octahedra. The corner-sharing octahedral tilt angles are 61°. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(5), one O(6), and two equivalent O(4) atoms to form PO4 tetrahedra that share corners with two equivalent Al(1)O6 octahedra and corners with three equivalent Ca(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-62°. In the second P site, P(2) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form PO4 tetrahedra that share corners with two equivalent Al(1)O6 octahedra and corners with three equivalent Ca(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-65°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Ca(1), one Al(1), and one P(2) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Ca(1) and one P(2) atom. In the third O site, O(3) is bonded in a linear geometry to one Ca(2) and one P(2) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Ca(1), two equivalent Ca(2), and one P(1) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one Ca(1) and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted T-shaped geometry to two equivalent Al(1) and one P(1) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Ca(2) and two equivalent Al(1) atoms. is represented by the CIF card [CIF]
data_Ca2AlP2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.671
_cell_length_b   7.651
_cell_length_c   8.316
_cell_angle_alpha   66.969
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   332.029
_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  0.750  0.795  0.247  1.0
  Ca  Ca1  1  0.250  0.205  0.753  1.0
  Ca  Ca2  1  0.750  0.177  0.414  1.0
  Ca  Ca3  1  0.250  0.823  0.586  1.0
  Al  Al4  1  0.500  0.500  0.000  1.0
  Al  Al5  1  0.000  0.500  0.000  1.0
  P  P6  1  0.250  0.077  0.184  1.0
  P  P7  1  0.750  0.923  0.816  1.0
  P  P8  1  0.250  0.500  0.333  1.0
  P  P9  1  0.750  0.500  0.667  1.0
  O  O10  1  0.527  0.446  0.792  1.0
  O  O11  1  0.027  0.554  0.208  1.0
  O  O12  1  0.473  0.554  0.208  1.0
  O  O13  1  0.973  0.446  0.792  1.0
  O  O14  1  0.250  0.287  0.447  1.0
  O  O15  1  0.750  0.713  0.553  1.0
  O  O16  1  0.250  0.620  0.442  1.0
  O  O17  1  0.750  0.380  0.558  1.0
  O  O18  1  0.029  0.013  0.304  1.0
  O  O19  1  0.529  0.987  0.696  1.0
  O  O20  1  0.971  0.987  0.696  1.0
  O  O21  1  0.471  0.013  0.304  1.0
  O  O22  1  0.250  0.995  0.044  1.0
  O  O23  1  0.750  0.005  0.956  1.0
  O  O24  1  0.250  0.304  0.087  1.0
  O  O25  1  0.750  0.696  0.913  1.0
  O  O26  1  0.250  0.650  0.892  1.0
  O  O27  1  0.750  0.350  0.108  1.0
[/CIF]
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