The compound described by K3Si3N5 crystallizes in the triclinic P-1 space group. There are three inequivalent K sites. In the first K site, K(1) is bonded in a 6-coordinate geometry to one N(1), one N(3), one N(4), one N(5), and two equivalent N(2) atoms. In the second K site, K(2) is bonded in a 3-coordinate geometry to one N(3) and two equivalent N(5) atoms. In the third K site, K(3) is bonded in a 5-coordinate geometry to one N(1), one N(2), one N(4), and two equivalent N(3) atoms. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to one N(1), one N(5), and two equivalent N(3) atoms to form a mixture of corner and edge-sharing SiN4 tetrahedra. In the second Si site, Si(2) is bonded to one N(1), one N(2), and two equivalent N(4) atoms to form a mixture of distorted corner and edge-sharing SiN4 tetrahedra. In the third Si site, Si(3) is bonded to one N(1), one N(2), one N(4), and one N(5) atom to form a mixture of corner and edge-sharing SiN4 tetrahedra. There are five inequivalent N sites. In the first N site, N(1) is bonded in a 3-coordinate geometry to one K(1), one K(3), one Si(1), one Si(2), and one Si(3) atom. In the second N site, N(2) is bonded in a 2-coordinate geometry to one K(3), two equivalent K(1), one Si(2), and one Si(3) atom. In the third N site, N(3) is bonded in a 6-coordinate geometry to one K(1), one K(2), two equivalent K(3), and two equivalent Si(1) atoms. In the fourth N site, N(4) is bonded in a 3-coordinate geometry to one K(1), one K(3), one Si(3), and two equivalent Si(2) atoms. In the fifth N site, N(5) is bonded in a 2-coordinate geometry to one K(1), two equivalent K(2), one Si(1), and one Si(3) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_K3Si3N5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.582
_cell_length_b   7.220
_cell_length_c   8.234
_cell_angle_alpha   105.766
_cell_angle_beta   94.690
_cell_angle_gamma   100.906
_symmetry_Int_Tables_number   1
_cell_volume   310.472
_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
  K  K0  1  0.833  0.428  0.615  1.0
  K  K1  1  0.167  0.572  0.385  1.0
  K  K2  1  0.629  0.825  0.910  1.0
  K  K3  1  0.371  0.175  0.090  1.0
  K  K4  1  0.648  0.620  0.244  1.0
  K  K5  1  0.352  0.380  0.756  1.0
  Si  Si6  1  0.933  0.323  0.983  1.0
  Si  Si7  1  0.067  0.677  0.017  1.0
  Si  Si8  1  0.687  0.975  0.594  1.0
  Si  Si9  1  0.313  0.025  0.406  1.0
  Si  Si10  1  0.076  0.906  0.717  1.0
  Si  Si11  1  0.924  0.094  0.283  1.0
  N  N12  1  0.918  0.123  0.778  1.0
  N  N13  1  0.082  0.877  0.222  1.0
  N  N14  1  0.817  0.774  0.570  1.0
  N  N15  1  0.183  0.226  0.430  1.0
  N  N16  1  0.781  0.502  0.945  1.0
  N  N17  1  0.219  0.498  0.055  1.0
  N  N18  1  0.354  0.959  0.604  1.0
  N  N19  1  0.646  0.041  0.396  1.0
  N  N20  1  0.151  0.800  0.868  1.0
  N  N21  1  0.849  0.200  0.132  1.0
[/CIF]
.
The compound described by K3Si3N5 crystallizes in the triclinic P-1 space group. There are three inequivalent K sites. In the first K site, K(1) is bonded in a 6-coordinate geometry to one N(1), one N(3), one N(4), one N(5), and two equivalent N(2) atoms. In the second K site, K(2) is bonded in a 3-coordinate geometry to one N(3) and two equivalent N(5) atoms. In the third K site, K(3) is bonded in a 5-coordinate geometry to one N(1), one N(2), one N(4), and two equivalent N(3) atoms. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to one N(1), one N(5), and two equivalent N(3) atoms to form a mixture of corner and edge-sharing SiN4 tetrahedra. In the second Si site, Si(2) is bonded to one N(1), one N(2), and two equivalent N(4) atoms to form a mixture of distorted corner and edge-sharing SiN4 tetrahedra. In the third Si site, Si(3) is bonded to one N(1), one N(2), one N(4), and one N(5) atom to form a mixture of corner and edge-sharing SiN4 tetrahedra. There are five inequivalent N sites. In the first N site, N(1) is bonded in a 3-coordinate geometry to one K(1), one K(3), one Si(1), one Si(2), and one Si(3) atom. In the second N site, N(2) is bonded in a 2-coordinate geometry to one K(3), two equivalent K(1), one Si(2), and one Si(3) atom. In the third N site, N(3) is bonded in a 6-coordinate geometry to one K(1), one K(2), two equivalent K(3), and two equivalent Si(1) atoms. In the fourth N site, N(4) is bonded in a 3-coordinate geometry to one K(1), one K(3), one Si(3), and two equivalent Si(2) atoms. In the fifth N site, N(5) is bonded in a 2-coordinate geometry to one K(1), two equivalent K(2), one Si(1), and one Si(3) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_K3Si3N5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.582
_cell_length_b   7.220
_cell_length_c   8.234
_cell_angle_alpha   105.766
_cell_angle_beta   94.690
_cell_angle_gamma   100.906
_symmetry_Int_Tables_number   1
_cell_volume   310.472
_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
  K  K0  1  0.833  0.428  0.615  1.0
  K  K1  1  0.167  0.572  0.385  1.0
  K  K2  1  0.629  0.825  0.910  1.0
  K  K3  1  0.371  0.175  0.090  1.0
  K  K4  1  0.648  0.620  0.244  1.0
  K  K5  1  0.352  0.380  0.756  1.0
  Si  Si6  1  0.933  0.323  0.983  1.0
  Si  Si7  1  0.067  0.677  0.017  1.0
  Si  Si8  1  0.687  0.975  0.594  1.0
  Si  Si9  1  0.313  0.025  0.406  1.0
  Si  Si10  1  0.076  0.906  0.717  1.0
  Si  Si11  1  0.924  0.094  0.283  1.0
  N  N12  1  0.918  0.123  0.778  1.0
  N  N13  1  0.082  0.877  0.222  1.0
  N  N14  1  0.817  0.774  0.570  1.0
  N  N15  1  0.183  0.226  0.430  1.0
  N  N16  1  0.781  0.502  0.945  1.0
  N  N17  1  0.219  0.498  0.055  1.0
  N  N18  1  0.354  0.959  0.604  1.0
  N  N19  1  0.646  0.041  0.396  1.0
  N  N20  1  0.151  0.800  0.868  1.0
  N  N21  1  0.849  0.200  0.132  1.0
[/CIF]
.