The structure described by Na2CrSiCO7 crystallizes in the monoclinic P2_1/m space group. Na(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom. Cr(1) is bonded to one O(2), one O(3), one O(4), one O(5), and two equivalent O(6) atoms to form CrO6 octahedra that share corners with four equivalent Si(1)O4 tetrahedra. Si(1) is bonded to one O(4), one O(5), and two equivalent O(6) atoms to form SiO4 tetrahedra that share corners with four equivalent Cr(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 39-50°. C(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Na(1) and one C(1) atom. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Na(1), one Cr(1), and one C(1) atom. In the third O site, O(3) is bonded in a distorted tetrahedral geometry to two equivalent Na(1), one Cr(1), and one C(1) atom. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to two equivalent Na(1), one Cr(1), and one Si(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent Na(1), one Cr(1), and one Si(1) atom. In the sixth O site, O(6) is bonded in a 2-coordinate geometry to one Na(1), one Cr(1), and one Si(1) atom. is represented by the CIF card [CIF]
data_Na2CrSiCO7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.259
_cell_length_b   6.449
_cell_length_c   9.066
_cell_angle_alpha   90.002
_cell_angle_beta   91.691
_cell_angle_gamma   90.003
_symmetry_Int_Tables_number   1
_cell_volume   307.391
_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
  C  C0  1  0.728  0.750  0.919  1.0
  C  C1  1  0.272  0.250  0.081  1.0
  Cr  Cr2  1  0.802  0.750  0.650  1.0
  Cr  Cr3  1  0.199  0.250  0.350  1.0
  Na  Na4  1  0.245  0.010  0.766  1.0
  Na  Na5  1  0.245  0.490  0.766  1.0
  Na  Na6  1  0.755  0.510  0.234  1.0
  Na  Na7  1  0.755  0.990  0.234  1.0
  O  O8  1  0.310  0.250  0.946  1.0
  O  O9  1  0.690  0.750  0.054  1.0
  O  O10  1  0.954  0.750  0.860  1.0
  O  O11  1  0.046  0.250  0.140  1.0
  O  O12  1  0.542  0.750  0.817  1.0
  O  O13  1  0.458  0.250  0.183  1.0
  O  O14  1  0.137  0.750  0.583  1.0
  O  O15  1  0.863  0.250  0.417  1.0
  O  O16  1  0.395  0.250  0.539  1.0
  O  O17  1  0.605  0.750  0.461  1.0
  O  O18  1  0.785  0.043  0.668  1.0
  O  O19  1  0.785  0.457  0.668  1.0
  O  O20  1  0.215  0.543  0.332  1.0
  O  O21  1  0.215  0.957  0.332  1.0
  Si  Si22  1  0.704  0.250  0.571  1.0
  Si  Si23  1  0.296  0.750  0.429  1.0
[/CIF]
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The structure described by Na2CrSiCO7 crystallizes in the monoclinic P2_1/m space group. Na(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom. Cr(1) is bonded to one O(2), one O(3), one O(4), one O(5), and two equivalent O(6) atoms to form CrO6 octahedra that share corners with four equivalent Si(1)O4 tetrahedra. Si(1) is bonded to one O(4), one O(5), and two equivalent O(6) atoms to form SiO4 tetrahedra that share corners with four equivalent Cr(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 39-50°. C(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Na(1) and one C(1) atom. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Na(1), one Cr(1), and one C(1) atom. In the third O site, O(3) is bonded in a distorted tetrahedral geometry to two equivalent Na(1), one Cr(1), and one C(1) atom. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to two equivalent Na(1), one Cr(1), and one Si(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent Na(1), one Cr(1), and one Si(1) atom. In the sixth O site, O(6) is bonded in a 2-coordinate geometry to one Na(1), one Cr(1), and one Si(1) atom. is represented by the CIF card [CIF]
data_Na2CrSiCO7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.259
_cell_length_b   6.449
_cell_length_c   9.066
_cell_angle_alpha   90.002
_cell_angle_beta   91.691
_cell_angle_gamma   90.003
_symmetry_Int_Tables_number   1
_cell_volume   307.391
_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
  C  C0  1  0.728  0.750  0.919  1.0
  C  C1  1  0.272  0.250  0.081  1.0
  Cr  Cr2  1  0.802  0.750  0.650  1.0
  Cr  Cr3  1  0.199  0.250  0.350  1.0
  Na  Na4  1  0.245  0.010  0.766  1.0
  Na  Na5  1  0.245  0.490  0.766  1.0
  Na  Na6  1  0.755  0.510  0.234  1.0
  Na  Na7  1  0.755  0.990  0.234  1.0
  O  O8  1  0.310  0.250  0.946  1.0
  O  O9  1  0.690  0.750  0.054  1.0
  O  O10  1  0.954  0.750  0.860  1.0
  O  O11  1  0.046  0.250  0.140  1.0
  O  O12  1  0.542  0.750  0.817  1.0
  O  O13  1  0.458  0.250  0.183  1.0
  O  O14  1  0.137  0.750  0.583  1.0
  O  O15  1  0.863  0.250  0.417  1.0
  O  O16  1  0.395  0.250  0.539  1.0
  O  O17  1  0.605  0.750  0.461  1.0
  O  O18  1  0.785  0.043  0.668  1.0
  O  O19  1  0.785  0.457  0.668  1.0
  O  O20  1  0.215  0.543  0.332  1.0
  O  O21  1  0.215  0.957  0.332  1.0
  Si  Si22  1  0.704  0.250  0.571  1.0
  Si  Si23  1  0.296  0.750  0.429  1.0
[/CIF]
.