The crystal structure described by K2Ce(Si2O5)3 crystallizes in the monoclinic C2/c space group. K(1) is bonded in a 9-coordinate geometry to one O(2), one O(3), one O(4), one O(5), one O(6), two equivalent O(7), and two equivalent O(8) atoms. Ce(1) is bonded to two equivalent O(6), two equivalent O(7), and two equivalent O(8) atoms to form CeO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and corners with two equivalent Si(3)O4 tetrahedra. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(4), one O(5), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Ce(1)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, and corners with two equivalent Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles are 43°. In the second Si site, Si(2) is bonded to one O(1), one O(2), one O(3), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Ce(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles are 43°. In the third Si site, Si(3) is bonded to one O(2), one O(4), one O(5), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Ce(1)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 44°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to one K(1), one Si(2), and one Si(3) atom. In the third O site, O(3) is bonded in a 2-coordinate geometry to two equivalent K(1) and two equivalent Si(2) atoms. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one K(1), one Si(1), and one Si(3) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one K(1), one Si(1), and one Si(3) atom. In the sixth O site, O(6) is bonded in a 2-coordinate geometry to one K(1), one Ce(1), and one Si(2) atom. In the seventh O site, O(7) is bonded in a 2-coordinate geometry to two equivalent K(1), one Ce(1), and one Si(1) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to two equivalent K(1), one Ce(1), and one Si(3) atom. is represented by the CIF card [CIF]
data_K2Ce(Si2O5)3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.969
_cell_length_b   9.969
_cell_length_c   12.013
_cell_angle_alpha   52.992
_cell_angle_beta   52.992
_cell_angle_gamma   52.627
_symmetry_Int_Tables_number   1
_cell_volume   702.998
_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  0.903  0.254  0.499  1.0
  K  K1  1  0.746  0.097  0.001  1.0
  K  K2  1  0.097  0.746  0.501  1.0
  K  K3  1  0.254  0.903  0.999  1.0
  Ce  Ce4  1  0.167  0.833  0.750  1.0
  Ce  Ce5  1  0.833  0.167  0.250  1.0
  Si  Si6  1  0.253  0.197  0.123  1.0
  Si  Si7  1  0.803  0.747  0.377  1.0
  Si  Si8  1  0.564  0.628  0.226  1.0
  Si  Si9  1  0.436  0.372  0.774  1.0
  Si  Si10  1  0.427  0.901  0.356  1.0
  Si  Si11  1  0.197  0.253  0.623  1.0
  Si  Si12  1  0.628  0.564  0.726  1.0
  Si  Si13  1  0.573  0.099  0.644  1.0
  Si  Si14  1  0.372  0.436  0.274  1.0
  Si  Si15  1  0.901  0.427  0.856  1.0
  Si  Si16  1  0.747  0.803  0.877  1.0
  Si  Si17  1  0.099  0.573  0.144  1.0
  O  O18  1  0.627  0.775  0.055  1.0
  O  O19  1  0.278  0.531  0.157  1.0
  O  O20  1  0.722  0.469  0.843  1.0
  O  O21  1  0.607  0.393  0.750  1.0
  O  O22  1  0.469  0.722  0.343  1.0
  O  O23  1  0.593  0.922  0.801  1.0
  O  O24  1  0.393  0.607  0.250  1.0
  O  O25  1  0.606  0.867  0.361  1.0
  O  O26  1  0.273  0.567  0.743  1.0
  O  O27  1  0.394  0.133  0.639  1.0
  O  O28  1  0.433  0.727  0.757  1.0
  O  O29  1  0.407  0.078  0.199  1.0
  O  O30  1  0.078  0.407  0.699  1.0
  O  O31  1  0.877  0.908  0.795  1.0
  O  O32  1  0.225  0.373  0.445  1.0
  O  O33  1  0.775  0.627  0.555  1.0
  O  O34  1  0.531  0.278  0.657  1.0
  O  O35  1  0.867  0.606  0.861  1.0
  O  O36  1  0.242  0.938  0.499  1.0
  O  O37  1  0.567  0.273  0.243  1.0
  O  O38  1  0.123  0.092  0.205  1.0
  O  O39  1  0.062  0.758  0.001  1.0
  O  O40  1  0.092  0.123  0.705  1.0
  O  O41  1  0.908  0.877  0.295  1.0
  O  O42  1  0.938  0.242  0.999  1.0
  O  O43  1  0.922  0.593  0.301  1.0
  O  O44  1  0.727  0.433  0.257  1.0
  O  O45  1  0.758  0.062  0.501  1.0
  O  O46  1  0.133  0.394  0.139  1.0
  O  O47  1  0.373  0.225  0.945  1.0
[/CIF]
.
The crystal structure described by K2Ce(Si2O5)3 crystallizes in the monoclinic C2/c space group. K(1) is bonded in a 9-coordinate geometry to one O(2), one O(3), one O(4), one O(5), one O(6), two equivalent O(7), and two equivalent O(8) atoms. Ce(1) is bonded to two equivalent O(6), two equivalent O(7), and two equivalent O(8) atoms to form CeO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and corners with two equivalent Si(3)O4 tetrahedra. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(4), one O(5), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Ce(1)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, and corners with two equivalent Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles are 43°. In the second Si site, Si(2) is bonded to one O(1), one O(2), one O(3), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Ce(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles are 43°. In the third Si site, Si(3) is bonded to one O(2), one O(4), one O(5), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Ce(1)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 44°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to one K(1), one Si(2), and one Si(3) atom. In the third O site, O(3) is bonded in a 2-coordinate geometry to two equivalent K(1) and two equivalent Si(2) atoms. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one K(1), one Si(1), and one Si(3) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one K(1), one Si(1), and one Si(3) atom. In the sixth O site, O(6) is bonded in a 2-coordinate geometry to one K(1), one Ce(1), and one Si(2) atom. In the seventh O site, O(7) is bonded in a 2-coordinate geometry to two equivalent K(1), one Ce(1), and one Si(1) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to two equivalent K(1), one Ce(1), and one Si(3) atom. is represented by the CIF card [CIF]
data_K2Ce(Si2O5)3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.969
_cell_length_b   9.969
_cell_length_c   12.013
_cell_angle_alpha   52.992
_cell_angle_beta   52.992
_cell_angle_gamma   52.627
_symmetry_Int_Tables_number   1
_cell_volume   702.998
_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  0.903  0.254  0.499  1.0
  K  K1  1  0.746  0.097  0.001  1.0
  K  K2  1  0.097  0.746  0.501  1.0
  K  K3  1  0.254  0.903  0.999  1.0
  Ce  Ce4  1  0.167  0.833  0.750  1.0
  Ce  Ce5  1  0.833  0.167  0.250  1.0
  Si  Si6  1  0.253  0.197  0.123  1.0
  Si  Si7  1  0.803  0.747  0.377  1.0
  Si  Si8  1  0.564  0.628  0.226  1.0
  Si  Si9  1  0.436  0.372  0.774  1.0
  Si  Si10  1  0.427  0.901  0.356  1.0
  Si  Si11  1  0.197  0.253  0.623  1.0
  Si  Si12  1  0.628  0.564  0.726  1.0
  Si  Si13  1  0.573  0.099  0.644  1.0
  Si  Si14  1  0.372  0.436  0.274  1.0
  Si  Si15  1  0.901  0.427  0.856  1.0
  Si  Si16  1  0.747  0.803  0.877  1.0
  Si  Si17  1  0.099  0.573  0.144  1.0
  O  O18  1  0.627  0.775  0.055  1.0
  O  O19  1  0.278  0.531  0.157  1.0
  O  O20  1  0.722  0.469  0.843  1.0
  O  O21  1  0.607  0.393  0.750  1.0
  O  O22  1  0.469  0.722  0.343  1.0
  O  O23  1  0.593  0.922  0.801  1.0
  O  O24  1  0.393  0.607  0.250  1.0
  O  O25  1  0.606  0.867  0.361  1.0
  O  O26  1  0.273  0.567  0.743  1.0
  O  O27  1  0.394  0.133  0.639  1.0
  O  O28  1  0.433  0.727  0.757  1.0
  O  O29  1  0.407  0.078  0.199  1.0
  O  O30  1  0.078  0.407  0.699  1.0
  O  O31  1  0.877  0.908  0.795  1.0
  O  O32  1  0.225  0.373  0.445  1.0
  O  O33  1  0.775  0.627  0.555  1.0
  O  O34  1  0.531  0.278  0.657  1.0
  O  O35  1  0.867  0.606  0.861  1.0
  O  O36  1  0.242  0.938  0.499  1.0
  O  O37  1  0.567  0.273  0.243  1.0
  O  O38  1  0.123  0.092  0.205  1.0
  O  O39  1  0.062  0.758  0.001  1.0
  O  O40  1  0.092  0.123  0.705  1.0
  O  O41  1  0.908  0.877  0.295  1.0
  O  O42  1  0.938  0.242  0.999  1.0
  O  O43  1  0.922  0.593  0.301  1.0
  O  O44  1  0.727  0.433  0.257  1.0
  O  O45  1  0.758  0.062  0.501  1.0
  O  O46  1  0.133  0.394  0.139  1.0
  O  O47  1  0.373  0.225  0.945  1.0
[/CIF]
.