The crystal structure described by Cr(Si2O5)2 crystallizes in the triclinic P-1 space group. Cr(1) is bonded to one O(7), one O(8), one O(9), and two equivalent O(10) atoms to form distorted CrO5 trigonal bipyramids that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra, and  an edgeedge with one Cr(1)O5 trigonal bipyramid. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(3), one O(5), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and  a cornercorner with one Cr(1)O5 trigonal bipyramid. In the second Si site, Si(2) is bonded to one O(1), one O(2), one O(6), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and  a cornercorner with one Cr(1)O5 trigonal bipyramid. In the third Si site, Si(3) is bonded to one O(2), one O(3), one O(4), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and  a cornercorner with one Cr(1)O5 trigonal bipyramid. In the fourth Si site, Si(4) is bonded to one O(10), one O(4), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and corners with two equivalent Cr(1)O5 trigonal bipyramids. There are ten 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 bent 150 degrees geometry to one Si(2) and one Si(3) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(3) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one Si(3) and one Si(4) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(4) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one Si(2) and one Si(4) atom. In the seventh O site, O(7) is bonded in a bent 120 degrees geometry to one Cr(1) and one Si(1) atom. In the eighth O site, O(8) is bonded in a bent 150 degrees geometry to one Cr(1) and one Si(2) atom. In the ninth O site, O(9) is bonded in a bent 150 degrees geometry to one Cr(1) and one Si(3) atom. In the tenth O site, O(10) is bonded in a distorted trigonal planar geometry to two equivalent Cr(1) and one Si(4) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Cr(Si2O5)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.161
_cell_length_b   7.979
_cell_length_c   9.560
_cell_angle_alpha   105.054
_cell_angle_beta   101.658
_cell_angle_gamma   112.904
_symmetry_Int_Tables_number   1
_cell_volume   456.802
_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
  Cr  Cr0  1  0.260  0.322  0.417  1.0
  Cr  Cr1  1  0.740  0.678  0.583  1.0
  Si  Si2  1  0.924  0.302  0.132  1.0
  Si  Si3  1  0.227  0.914  0.213  1.0
  Si  Si4  1  0.798  0.626  0.246  1.0
  Si  Si5  1  0.381  0.622  0.245  1.0
  Si  Si6  1  0.619  0.378  0.755  1.0
  Si  Si7  1  0.202  0.374  0.754  1.0
  Si  Si8  1  0.773  0.086  0.787  1.0
  Si  Si9  1  0.076  0.698  0.868  1.0
  O  O10  1  0.211  0.882  0.035  1.0
  O  O11  1  0.987  0.795  0.219  1.0
  O  O12  1  0.777  0.410  0.167  1.0
  O  O13  1  0.569  0.624  0.175  1.0
  O  O14  1  0.146  0.459  0.118  1.0
  O  O15  1  0.389  0.836  0.289  1.0
  O  O16  1  0.997  0.234  0.270  1.0
  O  O17  1  0.333  0.146  0.319  1.0
  O  O18  1  0.855  0.685  0.433  1.0
  O  O19  1  0.420  0.561  0.400  1.0
  O  O20  1  0.580  0.439  0.600  1.0
  O  O21  1  0.145  0.315  0.567  1.0
  O  O22  1  0.667  0.854  0.681  1.0
  O  O23  1  0.003  0.766  0.730  1.0
  O  O24  1  0.611  0.164  0.711  1.0
  O  O25  1  0.854  0.541  0.882  1.0
  O  O26  1  0.431  0.376  0.825  1.0
  O  O27  1  0.223  0.590  0.833  1.0
  O  O28  1  0.013  0.205  0.781  1.0
  O  O29  1  0.789  0.118  0.965  1.0
[/CIF]
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The crystal structure described by Cr(Si2O5)2 crystallizes in the triclinic P-1 space group. Cr(1) is bonded to one O(7), one O(8), one O(9), and two equivalent O(10) atoms to form distorted CrO5 trigonal bipyramids that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra, and  an edgeedge with one Cr(1)O5 trigonal bipyramid. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(3), one O(5), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and  a cornercorner with one Cr(1)O5 trigonal bipyramid. In the second Si site, Si(2) is bonded to one O(1), one O(2), one O(6), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and  a cornercorner with one Cr(1)O5 trigonal bipyramid. In the third Si site, Si(3) is bonded to one O(2), one O(3), one O(4), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and  a cornercorner with one Cr(1)O5 trigonal bipyramid. In the fourth Si site, Si(4) is bonded to one O(10), one O(4), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and corners with two equivalent Cr(1)O5 trigonal bipyramids. There are ten 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 bent 150 degrees geometry to one Si(2) and one Si(3) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(3) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one Si(3) and one Si(4) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(4) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one Si(2) and one Si(4) atom. In the seventh O site, O(7) is bonded in a bent 120 degrees geometry to one Cr(1) and one Si(1) atom. In the eighth O site, O(8) is bonded in a bent 150 degrees geometry to one Cr(1) and one Si(2) atom. In the ninth O site, O(9) is bonded in a bent 150 degrees geometry to one Cr(1) and one Si(3) atom. In the tenth O site, O(10) is bonded in a distorted trigonal planar geometry to two equivalent Cr(1) and one Si(4) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Cr(Si2O5)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.161
_cell_length_b   7.979
_cell_length_c   9.560
_cell_angle_alpha   105.054
_cell_angle_beta   101.658
_cell_angle_gamma   112.904
_symmetry_Int_Tables_number   1
_cell_volume   456.802
_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
  Cr  Cr0  1  0.260  0.322  0.417  1.0
  Cr  Cr1  1  0.740  0.678  0.583  1.0
  Si  Si2  1  0.924  0.302  0.132  1.0
  Si  Si3  1  0.227  0.914  0.213  1.0
  Si  Si4  1  0.798  0.626  0.246  1.0
  Si  Si5  1  0.381  0.622  0.245  1.0
  Si  Si6  1  0.619  0.378  0.755  1.0
  Si  Si7  1  0.202  0.374  0.754  1.0
  Si  Si8  1  0.773  0.086  0.787  1.0
  Si  Si9  1  0.076  0.698  0.868  1.0
  O  O10  1  0.211  0.882  0.035  1.0
  O  O11  1  0.987  0.795  0.219  1.0
  O  O12  1  0.777  0.410  0.167  1.0
  O  O13  1  0.569  0.624  0.175  1.0
  O  O14  1  0.146  0.459  0.118  1.0
  O  O15  1  0.389  0.836  0.289  1.0
  O  O16  1  0.997  0.234  0.270  1.0
  O  O17  1  0.333  0.146  0.319  1.0
  O  O18  1  0.855  0.685  0.433  1.0
  O  O19  1  0.420  0.561  0.400  1.0
  O  O20  1  0.580  0.439  0.600  1.0
  O  O21  1  0.145  0.315  0.567  1.0
  O  O22  1  0.667  0.854  0.681  1.0
  O  O23  1  0.003  0.766  0.730  1.0
  O  O24  1  0.611  0.164  0.711  1.0
  O  O25  1  0.854  0.541  0.882  1.0
  O  O26  1  0.431  0.376  0.825  1.0
  O  O27  1  0.223  0.590  0.833  1.0
  O  O28  1  0.013  0.205  0.781  1.0
  O  O29  1  0.789  0.118  0.965  1.0
[/CIF]
.