The compound described by CaTi3(P2O7)2 crystallizes in the monoclinic P2_1/c space group. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(2), one O(3), one O(5), one O(6), and two equivalent O(7) atoms to form TiO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra,  an edgeedge with one Ti(1)O6 octahedra, and  an edgeedge with one Ti(2)O6 octahedra. In the second Ti site, Ti(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(6) atoms to form TiO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra, corners with four equivalent P(2)O4 tetrahedra, and edges with two equivalent Ti(1)O6 octahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form PO4 tetrahedra that share  a cornercorner with one Ti(2)O6 octahedra, corners with three equivalent Ti(1)O6 octahedra, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 47-58°. In the second P site, P(2) is bonded to one O(1), one O(4), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with two equivalent Ti(2)O6 octahedra, corners with three equivalent Ti(1)O6 octahedra, and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 34-59°. There are seven inequivalent O sites. In the first O site, O(5) is bonded in a 2-coordinate geometry to one Ca(1), one Ti(1), and one P(1) atom. In the second O site, O(6) is bonded in a 3-coordinate geometry to one Ti(1), one Ti(2), and one P(2) atom. In the third O site, O(7) is bonded in a distorted trigonal planar geometry to two equivalent Ti(1) and one P(2) atom. In the fourth O site, O(1) is bonded in a distorted trigonal planar geometry to one Ca(1), one Ti(2), and one P(2) atom. In the fifth O site, O(2) is bonded to one Ca(1), one Ti(1), one Ti(2), and one P(1) atom to form distorted corner-sharing OCaTi2P tetrahedra. In the sixth O site, O(3) is bonded in a 3-coordinate geometry to one Ca(1), one Ti(1), and one P(1) atom. In the seventh O site, O(4) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_CaTi3(P2O7)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.621
_cell_length_b   7.607
_cell_length_c   9.725
_cell_angle_alpha   69.790
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   529.102
_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  0.000  0.500  0.000  1.0
  Ca  Ca1  1  0.500  0.500  0.500  1.0
  Ti  Ti2  1  0.152  0.823  0.521  1.0
  Ti  Ti3  1  0.652  0.177  0.979  1.0
  Ti  Ti4  1  0.848  0.177  0.479  1.0
  Ti  Ti5  1  0.348  0.823  0.021  1.0
  Ti  Ti6  1  0.000  0.000  0.000  1.0
  Ti  Ti7  1  0.500  0.000  0.500  1.0
  P  P8  1  0.940  0.411  0.700  1.0
  P  P9  1  0.440  0.589  0.800  1.0
  P  P10  1  0.060  0.589  0.300  1.0
  P  P11  1  0.560  0.411  0.200  1.0
  P  P12  1  0.205  0.129  0.683  1.0
  P  P13  1  0.705  0.871  0.817  1.0
  P  P14  1  0.795  0.871  0.317  1.0
  P  P15  1  0.295  0.129  0.183  1.0
  O  O16  1  0.381  0.181  0.602  1.0
  O  O17  1  0.881  0.819  0.898  1.0
  O  O18  1  0.619  0.819  0.398  1.0
  O  O19  1  0.119  0.181  0.102  1.0
  O  O20  1  0.398  0.702  0.637  1.0
  O  O21  1  0.898  0.298  0.863  1.0
  O  O22  1  0.602  0.298  0.363  1.0
  O  O23  1  0.102  0.702  0.137  1.0
  O  O24  1  0.804  0.378  0.595  1.0
  O  O25  1  0.304  0.622  0.905  1.0
  O  O26  1  0.196  0.622  0.405  1.0
  O  O27  1  0.696  0.378  0.095  1.0
  O  O28  1  0.126  0.330  0.668  1.0
  O  O29  1  0.626  0.670  0.832  1.0
  O  O30  1  0.874  0.670  0.332  1.0
  O  O31  1  0.374  0.330  0.168  1.0
  O  O32  1  0.515  0.612  0.184  1.0
  O  O33  1  0.015  0.388  0.316  1.0
  O  O34  1  0.485  0.388  0.816  1.0
  O  O35  1  0.985  0.612  0.684  1.0
  O  O36  1  0.787  0.979  0.151  1.0
  O  O37  1  0.287  0.021  0.349  1.0
  O  O38  1  0.213  0.021  0.849  1.0
  O  O39  1  0.713  0.979  0.651  1.0
  O  O40  1  0.422  0.036  0.106  1.0
  O  O41  1  0.922  0.964  0.394  1.0
  O  O42  1  0.578  0.964  0.894  1.0
  O  O43  1  0.078  0.036  0.606  1.0
[/CIF]
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The compound described by CaTi3(P2O7)2 crystallizes in the monoclinic P2_1/c space group. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(2), one O(3), one O(5), one O(6), and two equivalent O(7) atoms to form TiO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra,  an edgeedge with one Ti(1)O6 octahedra, and  an edgeedge with one Ti(2)O6 octahedra. In the second Ti site, Ti(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(6) atoms to form TiO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra, corners with four equivalent P(2)O4 tetrahedra, and edges with two equivalent Ti(1)O6 octahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form PO4 tetrahedra that share  a cornercorner with one Ti(2)O6 octahedra, corners with three equivalent Ti(1)O6 octahedra, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 47-58°. In the second P site, P(2) is bonded to one O(1), one O(4), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with two equivalent Ti(2)O6 octahedra, corners with three equivalent Ti(1)O6 octahedra, and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 34-59°. There are seven inequivalent O sites. In the first O site, O(5) is bonded in a 2-coordinate geometry to one Ca(1), one Ti(1), and one P(1) atom. In the second O site, O(6) is bonded in a 3-coordinate geometry to one Ti(1), one Ti(2), and one P(2) atom. In the third O site, O(7) is bonded in a distorted trigonal planar geometry to two equivalent Ti(1) and one P(2) atom. In the fourth O site, O(1) is bonded in a distorted trigonal planar geometry to one Ca(1), one Ti(2), and one P(2) atom. In the fifth O site, O(2) is bonded to one Ca(1), one Ti(1), one Ti(2), and one P(1) atom to form distorted corner-sharing OCaTi2P tetrahedra. In the sixth O site, O(3) is bonded in a 3-coordinate geometry to one Ca(1), one Ti(1), and one P(1) atom. In the seventh O site, O(4) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_CaTi3(P2O7)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.621
_cell_length_b   7.607
_cell_length_c   9.725
_cell_angle_alpha   69.790
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   529.102
_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  0.000  0.500  0.000  1.0
  Ca  Ca1  1  0.500  0.500  0.500  1.0
  Ti  Ti2  1  0.152  0.823  0.521  1.0
  Ti  Ti3  1  0.652  0.177  0.979  1.0
  Ti  Ti4  1  0.848  0.177  0.479  1.0
  Ti  Ti5  1  0.348  0.823  0.021  1.0
  Ti  Ti6  1  0.000  0.000  0.000  1.0
  Ti  Ti7  1  0.500  0.000  0.500  1.0
  P  P8  1  0.940  0.411  0.700  1.0
  P  P9  1  0.440  0.589  0.800  1.0
  P  P10  1  0.060  0.589  0.300  1.0
  P  P11  1  0.560  0.411  0.200  1.0
  P  P12  1  0.205  0.129  0.683  1.0
  P  P13  1  0.705  0.871  0.817  1.0
  P  P14  1  0.795  0.871  0.317  1.0
  P  P15  1  0.295  0.129  0.183  1.0
  O  O16  1  0.381  0.181  0.602  1.0
  O  O17  1  0.881  0.819  0.898  1.0
  O  O18  1  0.619  0.819  0.398  1.0
  O  O19  1  0.119  0.181  0.102  1.0
  O  O20  1  0.398  0.702  0.637  1.0
  O  O21  1  0.898  0.298  0.863  1.0
  O  O22  1  0.602  0.298  0.363  1.0
  O  O23  1  0.102  0.702  0.137  1.0
  O  O24  1  0.804  0.378  0.595  1.0
  O  O25  1  0.304  0.622  0.905  1.0
  O  O26  1  0.196  0.622  0.405  1.0
  O  O27  1  0.696  0.378  0.095  1.0
  O  O28  1  0.126  0.330  0.668  1.0
  O  O29  1  0.626  0.670  0.832  1.0
  O  O30  1  0.874  0.670  0.332  1.0
  O  O31  1  0.374  0.330  0.168  1.0
  O  O32  1  0.515  0.612  0.184  1.0
  O  O33  1  0.015  0.388  0.316  1.0
  O  O34  1  0.485  0.388  0.816  1.0
  O  O35  1  0.985  0.612  0.684  1.0
  O  O36  1  0.787  0.979  0.151  1.0
  O  O37  1  0.287  0.021  0.349  1.0
  O  O38  1  0.213  0.021  0.849  1.0
  O  O39  1  0.713  0.979  0.651  1.0
  O  O40  1  0.422  0.036  0.106  1.0
  O  O41  1  0.922  0.964  0.394  1.0
  O  O42  1  0.578  0.964  0.894  1.0
  O  O43  1  0.078  0.036  0.606  1.0
[/CIF]
.