The material described by Ba2Ca(PO4)4 crystallizes in the monoclinic P2_1/c space group. Ba(1) is bonded in a 9-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(6), one O(7), one O(8), and two equivalent O(5) atoms. Ca(1) is bonded to two equivalent O(6), two equivalent O(7), and two equivalent O(8) atoms to form CaO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra and corners with four equivalent P(2)O4 tetrahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(4), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Ca(1)O6 octahedra. The corner-sharing octahedral tilt angles are 48°. In the second P site, P(2) is bonded to one O(3), one O(5), one O(6), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Ca(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 27-29°. There are eight inequivalent O sites. In the first O site, O(6) is bonded in a distorted bent 150 degrees geometry to one Ba(1), one Ca(1), and one P(2) atom. In the second O site, O(7) is bonded in a 3-coordinate geometry to one Ba(1), one Ca(1), and one P(1) atom. In the third O site, O(8) is bonded in a distorted bent 150 degrees geometry to one Ba(1), one Ca(1), and one P(2) atom. In the fourth O site, O(1) is bonded in a distorted bent 150 degrees geometry to one Ba(1) and one P(1) atom. In the fifth O site, O(2) is bonded in a distorted single-bond geometry to one Ba(1) and one P(1) atom. In the sixth O site, O(3) is bonded in a distorted single-bond geometry to one Ba(1) and one P(2) atom. In the seventh O site, O(4) is bonded in a distorted single-bond geometry to one Ba(1) and one P(1) atom. In the eighth O site, O(5) is bonded in a distorted single-bond geometry to two equivalent Ba(1) and one P(2) atom. is represented by the CIF card [CIF]
data_Ba2Ca(PO4)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.617
_cell_length_b   5.482
_cell_length_c   12.878
_cell_angle_alpha   79.753
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   737.543
_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
  Ba  Ba0  1  0.346  0.136  0.169  1.0
  Ba  Ba1  1  0.846  0.864  0.331  1.0
  Ba  Ba2  1  0.654  0.864  0.831  1.0
  Ba  Ba3  1  0.154  0.136  0.669  1.0
  Ca  Ca4  1  0.000  0.000  0.000  1.0
  Ca  Ca5  1  0.500  0.000  0.500  1.0
  P  P6  1  0.191  0.763  0.447  1.0
  P  P7  1  0.691  0.237  0.053  1.0
  P  P8  1  0.809  0.237  0.553  1.0
  P  P9  1  0.309  0.763  0.947  1.0
  P  P10  1  0.514  0.585  0.300  1.0
  P  P11  1  0.014  0.415  0.200  1.0
  P  P12  1  0.486  0.415  0.700  1.0
  P  P13  1  0.986  0.585  0.800  1.0
  O  O14  1  0.211  0.843  0.327  1.0
  O  O15  1  0.711  0.157  0.173  1.0
  O  O16  1  0.789  0.157  0.673  1.0
  O  O17  1  0.289  0.843  0.827  1.0
  O  O18  1  0.217  0.486  0.487  1.0
  O  O19  1  0.717  0.514  0.013  1.0
  O  O20  1  0.783  0.514  0.513  1.0
  O  O21  1  0.283  0.486  0.987  1.0
  O  O22  1  0.655  0.557  0.269  1.0
  O  O23  1  0.155  0.443  0.231  1.0
  O  O24  1  0.345  0.443  0.731  1.0
  O  O25  1  0.845  0.557  0.769  1.0
  O  O26  1  0.048  0.791  0.471  1.0
  O  O27  1  0.548  0.209  0.029  1.0
  O  O28  1  0.952  0.209  0.529  1.0
  O  O29  1  0.452  0.791  0.971  1.0
  O  O30  1  0.434  0.622  0.198  1.0
  O  O31  1  0.934  0.378  0.302  1.0
  O  O32  1  0.566  0.378  0.802  1.0
  O  O33  1  0.066  0.622  0.698  1.0
  O  O34  1  0.470  0.345  0.370  1.0
  O  O35  1  0.970  0.655  0.130  1.0
  O  O36  1  0.530  0.655  0.630  1.0
  O  O37  1  0.030  0.345  0.870  1.0
  O  O38  1  0.275  0.922  0.507  1.0
  O  O39  1  0.775  0.078  0.993  1.0
  O  O40  1  0.725  0.078  0.493  1.0
  O  O41  1  0.225  0.922  0.007  1.0
  O  O42  1  0.508  0.816  0.352  1.0
  O  O43  1  0.008  0.184  0.148  1.0
  O  O44  1  0.492  0.184  0.648  1.0
  O  O45  1  0.992  0.816  0.852  1.0
[/CIF]
.
The material described by Ba2Ca(PO4)4 crystallizes in the monoclinic P2_1/c space group. Ba(1) is bonded in a 9-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(6), one O(7), one O(8), and two equivalent O(5) atoms. Ca(1) is bonded to two equivalent O(6), two equivalent O(7), and two equivalent O(8) atoms to form CaO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra and corners with four equivalent P(2)O4 tetrahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(4), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Ca(1)O6 octahedra. The corner-sharing octahedral tilt angles are 48°. In the second P site, P(2) is bonded to one O(3), one O(5), one O(6), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Ca(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 27-29°. There are eight inequivalent O sites. In the first O site, O(6) is bonded in a distorted bent 150 degrees geometry to one Ba(1), one Ca(1), and one P(2) atom. In the second O site, O(7) is bonded in a 3-coordinate geometry to one Ba(1), one Ca(1), and one P(1) atom. In the third O site, O(8) is bonded in a distorted bent 150 degrees geometry to one Ba(1), one Ca(1), and one P(2) atom. In the fourth O site, O(1) is bonded in a distorted bent 150 degrees geometry to one Ba(1) and one P(1) atom. In the fifth O site, O(2) is bonded in a distorted single-bond geometry to one Ba(1) and one P(1) atom. In the sixth O site, O(3) is bonded in a distorted single-bond geometry to one Ba(1) and one P(2) atom. In the seventh O site, O(4) is bonded in a distorted single-bond geometry to one Ba(1) and one P(1) atom. In the eighth O site, O(5) is bonded in a distorted single-bond geometry to two equivalent Ba(1) and one P(2) atom. is represented by the CIF card [CIF]
data_Ba2Ca(PO4)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.617
_cell_length_b   5.482
_cell_length_c   12.878
_cell_angle_alpha   79.753
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   737.543
_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
  Ba  Ba0  1  0.346  0.136  0.169  1.0
  Ba  Ba1  1  0.846  0.864  0.331  1.0
  Ba  Ba2  1  0.654  0.864  0.831  1.0
  Ba  Ba3  1  0.154  0.136  0.669  1.0
  Ca  Ca4  1  0.000  0.000  0.000  1.0
  Ca  Ca5  1  0.500  0.000  0.500  1.0
  P  P6  1  0.191  0.763  0.447  1.0
  P  P7  1  0.691  0.237  0.053  1.0
  P  P8  1  0.809  0.237  0.553  1.0
  P  P9  1  0.309  0.763  0.947  1.0
  P  P10  1  0.514  0.585  0.300  1.0
  P  P11  1  0.014  0.415  0.200  1.0
  P  P12  1  0.486  0.415  0.700  1.0
  P  P13  1  0.986  0.585  0.800  1.0
  O  O14  1  0.211  0.843  0.327  1.0
  O  O15  1  0.711  0.157  0.173  1.0
  O  O16  1  0.789  0.157  0.673  1.0
  O  O17  1  0.289  0.843  0.827  1.0
  O  O18  1  0.217  0.486  0.487  1.0
  O  O19  1  0.717  0.514  0.013  1.0
  O  O20  1  0.783  0.514  0.513  1.0
  O  O21  1  0.283  0.486  0.987  1.0
  O  O22  1  0.655  0.557  0.269  1.0
  O  O23  1  0.155  0.443  0.231  1.0
  O  O24  1  0.345  0.443  0.731  1.0
  O  O25  1  0.845  0.557  0.769  1.0
  O  O26  1  0.048  0.791  0.471  1.0
  O  O27  1  0.548  0.209  0.029  1.0
  O  O28  1  0.952  0.209  0.529  1.0
  O  O29  1  0.452  0.791  0.971  1.0
  O  O30  1  0.434  0.622  0.198  1.0
  O  O31  1  0.934  0.378  0.302  1.0
  O  O32  1  0.566  0.378  0.802  1.0
  O  O33  1  0.066  0.622  0.698  1.0
  O  O34  1  0.470  0.345  0.370  1.0
  O  O35  1  0.970  0.655  0.130  1.0
  O  O36  1  0.530  0.655  0.630  1.0
  O  O37  1  0.030  0.345  0.870  1.0
  O  O38  1  0.275  0.922  0.507  1.0
  O  O39  1  0.775  0.078  0.993  1.0
  O  O40  1  0.725  0.078  0.493  1.0
  O  O41  1  0.225  0.922  0.007  1.0
  O  O42  1  0.508  0.816  0.352  1.0
  O  O43  1  0.008  0.184  0.148  1.0
  O  O44  1  0.492  0.184  0.648  1.0
  O  O45  1  0.992  0.816  0.852  1.0
[/CIF]
.