The material described by Cd2Si(P2O7)2 crystallizes in the monoclinic C2/c space group. Cd(1) is bonded to one O(3), one O(5), two equivalent O(6), and two equivalent O(7) atoms to form distorted CdO6 octahedra that share corners with two equivalent Cd(1)O6 octahedra, corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and  an edgeedge with one Cd(1)O6 octahedra. The corner-sharing octahedral tilt angles are 70°. Si(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form SiO4 tetrahedra that share corners with two equivalent P(1)O4 tetrahedra and corners with two 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(3), one O(4), and one O(6) atom to form PO4 tetrahedra that share corners with three equivalent Cd(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 32-55°. In the second P site, P(2) is bonded to one O(2), one O(4), one O(5), and one O(7) atom to form PO4 tetrahedra that share corners with three equivalent Cd(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 44-59°. There are seven inequivalent O sites. In the first O site, O(5) is bonded in a distorted bent 150 degrees geometry to one Cd(1) and one P(2) atom. In the second O site, O(6) is bonded in a distorted single-bond geometry to two equivalent Cd(1) and one P(1) atom. In the third O site, O(7) is bonded in a distorted trigonal planar geometry to two equivalent Cd(1) and one P(2) atom. In the fourth O site, O(1) is bonded in a bent 120 degrees geometry to one Si(1) and one P(1) atom. In the fifth O site, O(2) is bonded in a bent 150 degrees geometry to one Si(1) and one P(2) atom. In the sixth O site, O(3) is bonded in a bent 150 degrees geometry to one Cd(1) and one P(1) atom. In the seventh O site, O(4) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. is represented by the CIF file [CIF]
data_Cd2Si(P2O7)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.359
_cell_length_b   9.359
_cell_length_c   12.780
_cell_angle_alpha   77.439
_cell_angle_beta   77.439
_cell_angle_gamma   33.357
_symmetry_Int_Tables_number   1
_cell_volume   599.419
_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
  Cd  Cd0  1  0.104  0.386  0.371  1.0
  Cd  Cd1  1  0.614  0.896  0.129  1.0
  Cd  Cd2  1  0.386  0.104  0.871  1.0
  Cd  Cd3  1  0.896  0.614  0.629  1.0
  Si  Si4  1  0.623  0.377  0.250  1.0
  Si  Si5  1  0.377  0.623  0.750  1.0
  P  P6  1  0.647  0.101  0.428  1.0
  P  P7  1  0.285  0.477  0.139  1.0
  P  P8  1  0.101  0.647  0.928  1.0
  P  P9  1  0.477  0.285  0.639  1.0
  P  P10  1  0.523  0.715  0.361  1.0
  P  P11  1  0.899  0.353  0.072  1.0
  P  P12  1  0.715  0.523  0.861  1.0
  P  P13  1  0.353  0.899  0.572  1.0
  O  O14  1  0.771  0.122  0.332  1.0
  O  O15  1  0.381  0.529  0.188  1.0
  O  O16  1  0.367  0.322  0.404  1.0
  O  O17  1  0.181  0.653  0.027  1.0
  O  O18  1  0.122  0.771  0.832  1.0
  O  O19  1  0.529  0.381  0.688  1.0
  O  O20  1  0.525  0.192  0.120  1.0
  O  O21  1  0.809  0.830  0.450  1.0
  O  O22  1  0.053  0.585  0.202  1.0
  O  O23  1  0.322  0.367  0.904  1.0
  O  O24  1  0.653  0.181  0.527  1.0
  O  O25  1  0.192  0.525  0.620  1.0
  O  O26  1  0.830  0.809  0.950  1.0
  O  O27  1  0.585  0.053  0.702  1.0
  O  O28  1  0.415  0.947  0.298  1.0
  O  O29  1  0.170  0.191  0.050  1.0
  O  O30  1  0.808  0.475  0.380  1.0
  O  O31  1  0.347  0.819  0.473  1.0
  O  O32  1  0.678  0.633  0.096  1.0
  O  O33  1  0.947  0.415  0.798  1.0
  O  O34  1  0.191  0.170  0.550  1.0
  O  O35  1  0.475  0.808  0.880  1.0
  O  O36  1  0.471  0.619  0.312  1.0
  O  O37  1  0.878  0.229  0.168  1.0
  O  O38  1  0.819  0.347  0.973  1.0
  O  O39  1  0.633  0.678  0.596  1.0
  O  O40  1  0.619  0.471  0.812  1.0
  O  O41  1  0.229  0.878  0.668  1.0
[/CIF]
.
The material described by Cd2Si(P2O7)2 crystallizes in the monoclinic C2/c space group. Cd(1) is bonded to one O(3), one O(5), two equivalent O(6), and two equivalent O(7) atoms to form distorted CdO6 octahedra that share corners with two equivalent Cd(1)O6 octahedra, corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and  an edgeedge with one Cd(1)O6 octahedra. The corner-sharing octahedral tilt angles are 70°. Si(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form SiO4 tetrahedra that share corners with two equivalent P(1)O4 tetrahedra and corners with two 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(3), one O(4), and one O(6) atom to form PO4 tetrahedra that share corners with three equivalent Cd(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 32-55°. In the second P site, P(2) is bonded to one O(2), one O(4), one O(5), and one O(7) atom to form PO4 tetrahedra that share corners with three equivalent Cd(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 44-59°. There are seven inequivalent O sites. In the first O site, O(5) is bonded in a distorted bent 150 degrees geometry to one Cd(1) and one P(2) atom. In the second O site, O(6) is bonded in a distorted single-bond geometry to two equivalent Cd(1) and one P(1) atom. In the third O site, O(7) is bonded in a distorted trigonal planar geometry to two equivalent Cd(1) and one P(2) atom. In the fourth O site, O(1) is bonded in a bent 120 degrees geometry to one Si(1) and one P(1) atom. In the fifth O site, O(2) is bonded in a bent 150 degrees geometry to one Si(1) and one P(2) atom. In the sixth O site, O(3) is bonded in a bent 150 degrees geometry to one Cd(1) and one P(1) atom. In the seventh O site, O(4) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. is represented by the CIF file [CIF]
data_Cd2Si(P2O7)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.359
_cell_length_b   9.359
_cell_length_c   12.780
_cell_angle_alpha   77.439
_cell_angle_beta   77.439
_cell_angle_gamma   33.357
_symmetry_Int_Tables_number   1
_cell_volume   599.419
_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
  Cd  Cd0  1  0.104  0.386  0.371  1.0
  Cd  Cd1  1  0.614  0.896  0.129  1.0
  Cd  Cd2  1  0.386  0.104  0.871  1.0
  Cd  Cd3  1  0.896  0.614  0.629  1.0
  Si  Si4  1  0.623  0.377  0.250  1.0
  Si  Si5  1  0.377  0.623  0.750  1.0
  P  P6  1  0.647  0.101  0.428  1.0
  P  P7  1  0.285  0.477  0.139  1.0
  P  P8  1  0.101  0.647  0.928  1.0
  P  P9  1  0.477  0.285  0.639  1.0
  P  P10  1  0.523  0.715  0.361  1.0
  P  P11  1  0.899  0.353  0.072  1.0
  P  P12  1  0.715  0.523  0.861  1.0
  P  P13  1  0.353  0.899  0.572  1.0
  O  O14  1  0.771  0.122  0.332  1.0
  O  O15  1  0.381  0.529  0.188  1.0
  O  O16  1  0.367  0.322  0.404  1.0
  O  O17  1  0.181  0.653  0.027  1.0
  O  O18  1  0.122  0.771  0.832  1.0
  O  O19  1  0.529  0.381  0.688  1.0
  O  O20  1  0.525  0.192  0.120  1.0
  O  O21  1  0.809  0.830  0.450  1.0
  O  O22  1  0.053  0.585  0.202  1.0
  O  O23  1  0.322  0.367  0.904  1.0
  O  O24  1  0.653  0.181  0.527  1.0
  O  O25  1  0.192  0.525  0.620  1.0
  O  O26  1  0.830  0.809  0.950  1.0
  O  O27  1  0.585  0.053  0.702  1.0
  O  O28  1  0.415  0.947  0.298  1.0
  O  O29  1  0.170  0.191  0.050  1.0
  O  O30  1  0.808  0.475  0.380  1.0
  O  O31  1  0.347  0.819  0.473  1.0
  O  O32  1  0.678  0.633  0.096  1.0
  O  O33  1  0.947  0.415  0.798  1.0
  O  O34  1  0.191  0.170  0.550  1.0
  O  O35  1  0.475  0.808  0.880  1.0
  O  O36  1  0.471  0.619  0.312  1.0
  O  O37  1  0.878  0.229  0.168  1.0
  O  O38  1  0.819  0.347  0.973  1.0
  O  O39  1  0.633  0.678  0.596  1.0
  O  O40  1  0.619  0.471  0.812  1.0
  O  O41  1  0.229  0.878  0.668  1.0
[/CIF]
.