The material structure described by Ca3(SiP2)2 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to one P(3), one P(4), two equivalent P(1), and two equivalent P(2) atoms to form a mixture of distorted edge and corner-sharing CaP6 octahedra. The corner-sharing octahedral tilt angles range from 4-11°. In the second Ca site, Ca(2) is bonded to one P(1), one P(2), two equivalent P(3), and two equivalent P(4) atoms to form a mixture of distorted edge and corner-sharing CaP6 octahedra. The corner-sharing octahedral tilt angles range from 3-9°. In the third Ca site, Ca(3) is bonded to one P(1), one P(2), two equivalent P(3), and two equivalent P(4) atoms to form a mixture of edge and corner-sharing CaP6 octahedra. The corner-sharing octahedral tilt angles range from 3-11°. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 4-coordinate geometry to one Si(2), one P(2), and two equivalent P(1) atoms. In the second Si site, Si(2) is bonded in a 3-coordinate geometry to one Si(1), one P(2), one P(3), and one P(4) atom. There are four inequivalent P sites. In the first P site, P(4) is bonded to one Ca(1), two equivalent Ca(2), two equivalent Ca(3), and one Si(2) atom to form PCa5Si octahedra that share  a cornercorner with one P(2)Ca4Si2 octahedra, corners with two equivalent P(3)Ca5Si octahedra, corners with four equivalent P(1)Ca4Si2 octahedra,  an edgeedge with one P(1)Ca4Si2 octahedra, edges with two equivalent P(4)Ca5Si octahedra, edges with three equivalent P(2)Ca4Si2 octahedra, and edges with four equivalent P(3)Ca5Si octahedra. The corner-sharing octahedral tilt angles range from 3-88°. In the second P site, P(1) is bonded to one Ca(2), one Ca(3), two equivalent Ca(1), and two equivalent Si(1) atoms to form PCa4Si2 octahedra that share corners with two equivalent P(2)Ca4Si2 octahedra, corners with two equivalent P(3)Ca5Si octahedra, corners with four equivalent P(4)Ca5Si octahedra,  an edgeedge with one P(4)Ca5Si octahedra, edges with two equivalent P(1)Ca4Si2 octahedra, edges with two equivalent P(3)Ca5Si octahedra, and edges with three equivalent P(2)Ca4Si2 octahedra. The corner-sharing octahedral tilt angles range from 3-94°. In the third P site, P(2) is bonded to one Ca(2), one Ca(3), two equivalent Ca(1), one Si(1), and one Si(2) atom to form PCa4Si2 octahedra that share  a cornercorner with one P(4)Ca5Si octahedra, corners with two equivalent P(1)Ca4Si2 octahedra, corners with two equivalent P(2)Ca4Si2 octahedra, corners with three equivalent P(3)Ca5Si octahedra, edges with two equivalent P(3)Ca5Si octahedra, edges with three equivalent P(1)Ca4Si2 octahedra, and edges with three equivalent P(4)Ca5Si octahedra. The corner-sharing octahedral tilt angles range from 6-94°. In the fourth P site, P(3) is bonded to one Ca(1), two equivalent Ca(2), two equivalent Ca(3), and one Si(2) atom to form PCa5Si octahedra that share corners with two equivalent P(1)Ca4Si2 octahedra, corners with two equivalent P(4)Ca5Si octahedra, corners with three equivalent P(2)Ca4Si2 octahedra, edges with two equivalent P(1)Ca4Si2 octahedra, edges with two equivalent P(2)Ca4Si2 octahedra, edges with two equivalent P(3)Ca5Si octahedra, and edges with four equivalent P(4)Ca5Si octahedra. The corner-sharing octahedral tilt angles range from 3-94°. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ca3(SiP2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   17.264
_cell_length_b   6.934
_cell_length_c   7.096
_cell_angle_alpha   68.184
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   788.564
_cell_formula_units_Z   4
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  0.316  0.488  0.216  1.0
  Ca  Ca1  1  0.816  0.012  0.784  1.0
  Ca  Ca2  1  0.684  0.512  0.784  1.0
  Ca  Ca3  1  0.184  0.988  0.216  1.0
  Ca  Ca4  1  0.062  0.488  0.256  1.0
  Ca  Ca5  1  0.562  0.012  0.744  1.0
  Ca  Ca6  1  0.938  0.512  0.744  1.0
  Ca  Ca7  1  0.438  0.988  0.256  1.0
  Ca  Ca8  1  0.558  0.495  0.261  1.0
  Ca  Ca9  1  0.058  0.005  0.739  1.0
  Ca  Ca10  1  0.442  0.505  0.739  1.0
  Ca  Ca11  1  0.942  0.995  0.261  1.0
  Si  Si12  1  0.742  0.086  0.316  1.0
  Si  Si13  1  0.242  0.414  0.684  1.0
  Si  Si14  1  0.258  0.914  0.684  1.0
  Si  Si15  1  0.758  0.586  0.316  1.0
  Si  Si16  1  0.872  0.472  0.212  1.0
  Si  Si17  1  0.372  0.028  0.788  1.0
  Si  Si18  1  0.128  0.528  0.788  1.0
  Si  Si19  1  0.628  0.972  0.212  1.0
  P  P20  1  0.700  0.277  0.499  1.0
  P  P21  1  0.200  0.223  0.501  1.0
  P  P22  1  0.300  0.723  0.501  1.0
  P  P23  1  0.800  0.777  0.499  1.0
  P  P24  1  0.814  0.279  0.046  1.0
  P  P25  1  0.314  0.221  0.954  1.0
  P  P26  1  0.186  0.721  0.954  1.0
  P  P27  1  0.686  0.779  0.046  1.0
  P  P28  1  0.932  0.261  0.492  1.0
  P  P29  1  0.432  0.239  0.508  1.0
  P  P30  1  0.068  0.739  0.508  1.0
  P  P31  1  0.568  0.761  0.492  1.0
  P  P32  1  0.562  0.243  0.011  1.0
  P  P33  1  0.062  0.257  0.989  1.0
  P  P34  1  0.438  0.757  0.989  1.0
  P  P35  1  0.938  0.743  0.011  1.0
[/CIF]
.
The material structure described by Ca3(SiP2)2 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to one P(3), one P(4), two equivalent P(1), and two equivalent P(2) atoms to form a mixture of distorted edge and corner-sharing CaP6 octahedra. The corner-sharing octahedral tilt angles range from 4-11°. In the second Ca site, Ca(2) is bonded to one P(1), one P(2), two equivalent P(3), and two equivalent P(4) atoms to form a mixture of distorted edge and corner-sharing CaP6 octahedra. The corner-sharing octahedral tilt angles range from 3-9°. In the third Ca site, Ca(3) is bonded to one P(1), one P(2), two equivalent P(3), and two equivalent P(4) atoms to form a mixture of edge and corner-sharing CaP6 octahedra. The corner-sharing octahedral tilt angles range from 3-11°. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 4-coordinate geometry to one Si(2), one P(2), and two equivalent P(1) atoms. In the second Si site, Si(2) is bonded in a 3-coordinate geometry to one Si(1), one P(2), one P(3), and one P(4) atom. There are four inequivalent P sites. In the first P site, P(4) is bonded to one Ca(1), two equivalent Ca(2), two equivalent Ca(3), and one Si(2) atom to form PCa5Si octahedra that share  a cornercorner with one P(2)Ca4Si2 octahedra, corners with two equivalent P(3)Ca5Si octahedra, corners with four equivalent P(1)Ca4Si2 octahedra,  an edgeedge with one P(1)Ca4Si2 octahedra, edges with two equivalent P(4)Ca5Si octahedra, edges with three equivalent P(2)Ca4Si2 octahedra, and edges with four equivalent P(3)Ca5Si octahedra. The corner-sharing octahedral tilt angles range from 3-88°. In the second P site, P(1) is bonded to one Ca(2), one Ca(3), two equivalent Ca(1), and two equivalent Si(1) atoms to form PCa4Si2 octahedra that share corners with two equivalent P(2)Ca4Si2 octahedra, corners with two equivalent P(3)Ca5Si octahedra, corners with four equivalent P(4)Ca5Si octahedra,  an edgeedge with one P(4)Ca5Si octahedra, edges with two equivalent P(1)Ca4Si2 octahedra, edges with two equivalent P(3)Ca5Si octahedra, and edges with three equivalent P(2)Ca4Si2 octahedra. The corner-sharing octahedral tilt angles range from 3-94°. In the third P site, P(2) is bonded to one Ca(2), one Ca(3), two equivalent Ca(1), one Si(1), and one Si(2) atom to form PCa4Si2 octahedra that share  a cornercorner with one P(4)Ca5Si octahedra, corners with two equivalent P(1)Ca4Si2 octahedra, corners with two equivalent P(2)Ca4Si2 octahedra, corners with three equivalent P(3)Ca5Si octahedra, edges with two equivalent P(3)Ca5Si octahedra, edges with three equivalent P(1)Ca4Si2 octahedra, and edges with three equivalent P(4)Ca5Si octahedra. The corner-sharing octahedral tilt angles range from 6-94°. In the fourth P site, P(3) is bonded to one Ca(1), two equivalent Ca(2), two equivalent Ca(3), and one Si(2) atom to form PCa5Si octahedra that share corners with two equivalent P(1)Ca4Si2 octahedra, corners with two equivalent P(4)Ca5Si octahedra, corners with three equivalent P(2)Ca4Si2 octahedra, edges with two equivalent P(1)Ca4Si2 octahedra, edges with two equivalent P(2)Ca4Si2 octahedra, edges with two equivalent P(3)Ca5Si octahedra, and edges with four equivalent P(4)Ca5Si octahedra. The corner-sharing octahedral tilt angles range from 3-94°. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ca3(SiP2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   17.264
_cell_length_b   6.934
_cell_length_c   7.096
_cell_angle_alpha   68.184
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   788.564
_cell_formula_units_Z   4
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  0.316  0.488  0.216  1.0
  Ca  Ca1  1  0.816  0.012  0.784  1.0
  Ca  Ca2  1  0.684  0.512  0.784  1.0
  Ca  Ca3  1  0.184  0.988  0.216  1.0
  Ca  Ca4  1  0.062  0.488  0.256  1.0
  Ca  Ca5  1  0.562  0.012  0.744  1.0
  Ca  Ca6  1  0.938  0.512  0.744  1.0
  Ca  Ca7  1  0.438  0.988  0.256  1.0
  Ca  Ca8  1  0.558  0.495  0.261  1.0
  Ca  Ca9  1  0.058  0.005  0.739  1.0
  Ca  Ca10  1  0.442  0.505  0.739  1.0
  Ca  Ca11  1  0.942  0.995  0.261  1.0
  Si  Si12  1  0.742  0.086  0.316  1.0
  Si  Si13  1  0.242  0.414  0.684  1.0
  Si  Si14  1  0.258  0.914  0.684  1.0
  Si  Si15  1  0.758  0.586  0.316  1.0
  Si  Si16  1  0.872  0.472  0.212  1.0
  Si  Si17  1  0.372  0.028  0.788  1.0
  Si  Si18  1  0.128  0.528  0.788  1.0
  Si  Si19  1  0.628  0.972  0.212  1.0
  P  P20  1  0.700  0.277  0.499  1.0
  P  P21  1  0.200  0.223  0.501  1.0
  P  P22  1  0.300  0.723  0.501  1.0
  P  P23  1  0.800  0.777  0.499  1.0
  P  P24  1  0.814  0.279  0.046  1.0
  P  P25  1  0.314  0.221  0.954  1.0
  P  P26  1  0.186  0.721  0.954  1.0
  P  P27  1  0.686  0.779  0.046  1.0
  P  P28  1  0.932  0.261  0.492  1.0
  P  P29  1  0.432  0.239  0.508  1.0
  P  P30  1  0.068  0.739  0.508  1.0
  P  P31  1  0.568  0.761  0.492  1.0
  P  P32  1  0.562  0.243  0.011  1.0
  P  P33  1  0.062  0.257  0.989  1.0
  P  P34  1  0.438  0.757  0.989  1.0
  P  P35  1  0.938  0.743  0.011  1.0
[/CIF]
.