The structure described by Cr5(Si2O7)2 crystallizes in the triclinic P-1 space group. There are three inequivalent Cr sites. In the first Cr site, Cr(1) is bonded in a distorted linear geometry to two equivalent O(2), two equivalent O(5), and two equivalent O(7) atoms. In the second Cr site, Cr(2) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(5), and one O(7) atom. In the third Cr site, Cr(3) is bonded in a 5-coordinate geometry to one O(2), one O(4), one O(7), and two equivalent O(6) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a distorted water-like geometry to one O(2), one O(3), one O(4), and one O(7) atom. In the second Si site, Si(2) is bonded in a 4-coordinate geometry to one O(1), one O(3), one O(5), and one O(6) atom. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to one Cr(2) and one Si(2) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Cr(1), one Cr(2), one Cr(3), and one Si(1) atom. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Si(1) and one Si(2) atom. In the fourth O site, O(4) is bonded in a single-bond geometry to one Cr(3) and one Si(1) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Cr(1), one Cr(2), and one Si(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to two equivalent Cr(3) and one Si(2) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Cr(1), one Cr(2), one Cr(3), and one Si(1) atom. is represented by the CIF file [CIF]
data_Cr5(Si2O7)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.398
_cell_length_b   7.882
_cell_length_c   5.671
_cell_angle_alpha   90.956
_cell_angle_beta   106.070
_cell_angle_gamma   112.105
_symmetry_Int_Tables_number   1
_cell_volume   291.674
_cell_formula_units_Z   1
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
  Cr  Cr0  1  0.000  0.000  0.000  1.0
  Cr  Cr1  1  0.812  0.075  0.388  1.0
  Cr  Cr2  1  0.698  0.645  0.581  1.0
  Cr  Cr3  1  0.302  0.355  0.419  1.0
  Cr  Cr4  1  0.188  0.925  0.612  1.0
  Si  Si5  1  0.864  0.497  0.233  1.0
  Si  Si6  1  0.390  0.778  0.209  1.0
  Si  Si7  1  0.610  0.222  0.791  1.0
  Si  Si8  1  0.136  0.503  0.767  1.0
  O  O9  1  0.582  0.861  0.207  1.0
  O  O10  1  0.957  0.785  0.349  1.0
  O  O11  1  0.261  0.548  0.008  1.0
  O  O12  1  0.749  0.414  0.356  1.0
  O  O13  1  0.262  0.009  0.223  1.0
  O  O14  1  0.429  0.660  0.405  1.0
  O  O15  1  0.028  0.315  0.235  1.0
  O  O16  1  0.972  0.685  0.765  1.0
  O  O17  1  0.571  0.340  0.595  1.0
  O  O18  1  0.738  0.991  0.777  1.0
  O  O19  1  0.251  0.586  0.644  1.0
  O  O20  1  0.739  0.452  0.992  1.0
  O  O21  1  0.043  0.215  0.651  1.0
  O  O22  1  0.418  0.139  0.793  1.0
[/CIF]
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The structure described by Cr5(Si2O7)2 crystallizes in the triclinic P-1 space group. There are three inequivalent Cr sites. In the first Cr site, Cr(1) is bonded in a distorted linear geometry to two equivalent O(2), two equivalent O(5), and two equivalent O(7) atoms. In the second Cr site, Cr(2) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(5), and one O(7) atom. In the third Cr site, Cr(3) is bonded in a 5-coordinate geometry to one O(2), one O(4), one O(7), and two equivalent O(6) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a distorted water-like geometry to one O(2), one O(3), one O(4), and one O(7) atom. In the second Si site, Si(2) is bonded in a 4-coordinate geometry to one O(1), one O(3), one O(5), and one O(6) atom. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to one Cr(2) and one Si(2) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Cr(1), one Cr(2), one Cr(3), and one Si(1) atom. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Si(1) and one Si(2) atom. In the fourth O site, O(4) is bonded in a single-bond geometry to one Cr(3) and one Si(1) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Cr(1), one Cr(2), and one Si(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to two equivalent Cr(3) and one Si(2) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Cr(1), one Cr(2), one Cr(3), and one Si(1) atom. is represented by the CIF file [CIF]
data_Cr5(Si2O7)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.398
_cell_length_b   7.882
_cell_length_c   5.671
_cell_angle_alpha   90.956
_cell_angle_beta   106.070
_cell_angle_gamma   112.105
_symmetry_Int_Tables_number   1
_cell_volume   291.674
_cell_formula_units_Z   1
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
  Cr  Cr0  1  0.000  0.000  0.000  1.0
  Cr  Cr1  1  0.812  0.075  0.388  1.0
  Cr  Cr2  1  0.698  0.645  0.581  1.0
  Cr  Cr3  1  0.302  0.355  0.419  1.0
  Cr  Cr4  1  0.188  0.925  0.612  1.0
  Si  Si5  1  0.864  0.497  0.233  1.0
  Si  Si6  1  0.390  0.778  0.209  1.0
  Si  Si7  1  0.610  0.222  0.791  1.0
  Si  Si8  1  0.136  0.503  0.767  1.0
  O  O9  1  0.582  0.861  0.207  1.0
  O  O10  1  0.957  0.785  0.349  1.0
  O  O11  1  0.261  0.548  0.008  1.0
  O  O12  1  0.749  0.414  0.356  1.0
  O  O13  1  0.262  0.009  0.223  1.0
  O  O14  1  0.429  0.660  0.405  1.0
  O  O15  1  0.028  0.315  0.235  1.0
  O  O16  1  0.972  0.685  0.765  1.0
  O  O17  1  0.571  0.340  0.595  1.0
  O  O18  1  0.738  0.991  0.777  1.0
  O  O19  1  0.251  0.586  0.644  1.0
  O  O20  1  0.739  0.452  0.992  1.0
  O  O21  1  0.043  0.215  0.651  1.0
  O  O22  1  0.418  0.139  0.793  1.0
[/CIF]
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