The crystal structure described by Cr2Zn3O7 crystallizes in the orthorhombic Cmc2_1 space group. Cr(1) is bonded to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms to form CrO6 octahedra that share corners with five equivalent Cr(1)O6 octahedra, corners with four equivalent Zn(1)O4 tetrahedra, and corners with five equivalent Zn(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 40-44°. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to two equivalent O(3) and two equivalent O(4) atoms to form distorted ZnO4 tetrahedra that share corners with eight equivalent Cr(1)O6 octahedra and corners with two equivalent Zn(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 65-84°. In the second Zn site, Zn(2) is bonded to one O(2) and three equivalent O(1) atoms to form distorted ZnO4 tetrahedra that share corners with five equivalent Cr(1)O6 octahedra and corners with six equivalent Zn(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 45-83°. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Cr(1) and three equivalent Zn(2) atoms to form OZn3Cr tetrahedra that share  a cornercorner with one O(4)Zn2Cr2 tetrahedra and corners with six equivalent O(1)Zn3Cr tetrahedra. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Cr(1) and one Zn(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to two equivalent Cr(1) and one Zn(1) atom. In the fourth O site, O(4) is bonded to two equivalent Cr(1) and two equivalent Zn(1) atoms to form OZn2Cr2 tetrahedra that share corners with two equivalent O(4)Zn2Cr2 tetrahedra and corners with two equivalent O(1)Zn3Cr tetrahedra. is represented by the CIF file [CIF]
data_Zn3Cr2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.627
_cell_length_b   9.627
_cell_length_c   5.121
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   148.847
_symmetry_Int_Tables_number   1
_cell_volume   245.515
_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
  Zn  Zn0  1  0.739  0.739  0.278  1.0
  Zn  Zn1  1  0.261  0.261  0.778  1.0
  Zn  Zn2  1  0.979  0.577  0.209  1.0
  Zn  Zn3  1  0.021  0.423  0.709  1.0
  Zn  Zn4  1  0.577  0.979  0.209  1.0
  Zn  Zn5  1  0.423  0.021  0.709  1.0
  Cr  Cr6  1  0.150  0.354  0.245  1.0
  Cr  Cr7  1  0.850  0.646  0.745  1.0
  Cr  Cr8  1  0.646  0.850  0.745  1.0
  Cr  Cr9  1  0.354  0.150  0.245  1.0
  O  O10  1  0.352  0.947  0.320  1.0
  O  O11  1  0.648  0.053  0.820  1.0
  O  O12  1  0.053  0.648  0.820  1.0
  O  O13  1  0.947  0.352  0.320  1.0
  O  O14  1  0.546  0.289  0.929  1.0
  O  O15  1  0.454  0.711  0.429  1.0
  O  O16  1  0.711  0.454  0.429  1.0
  O  O17  1  0.289  0.546  0.929  1.0
  O  O18  1  0.997  0.844  0.061  1.0
  O  O19  1  0.003  0.156  0.561  1.0
  O  O20  1  0.362  0.362  0.171  1.0
  O  O21  1  0.638  0.638  0.671  1.0
  O  O22  1  0.844  0.997  0.061  1.0
  O  O23  1  0.156  0.003  0.561  1.0
[/CIF]
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The crystal structure described by Cr2Zn3O7 crystallizes in the orthorhombic Cmc2_1 space group. Cr(1) is bonded to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms to form CrO6 octahedra that share corners with five equivalent Cr(1)O6 octahedra, corners with four equivalent Zn(1)O4 tetrahedra, and corners with five equivalent Zn(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 40-44°. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to two equivalent O(3) and two equivalent O(4) atoms to form distorted ZnO4 tetrahedra that share corners with eight equivalent Cr(1)O6 octahedra and corners with two equivalent Zn(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 65-84°. In the second Zn site, Zn(2) is bonded to one O(2) and three equivalent O(1) atoms to form distorted ZnO4 tetrahedra that share corners with five equivalent Cr(1)O6 octahedra and corners with six equivalent Zn(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 45-83°. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Cr(1) and three equivalent Zn(2) atoms to form OZn3Cr tetrahedra that share  a cornercorner with one O(4)Zn2Cr2 tetrahedra and corners with six equivalent O(1)Zn3Cr tetrahedra. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Cr(1) and one Zn(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to two equivalent Cr(1) and one Zn(1) atom. In the fourth O site, O(4) is bonded to two equivalent Cr(1) and two equivalent Zn(1) atoms to form OZn2Cr2 tetrahedra that share corners with two equivalent O(4)Zn2Cr2 tetrahedra and corners with two equivalent O(1)Zn3Cr tetrahedra. is represented by the CIF file [CIF]
data_Zn3Cr2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.627
_cell_length_b   9.627
_cell_length_c   5.121
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   148.847
_symmetry_Int_Tables_number   1
_cell_volume   245.515
_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
  Zn  Zn0  1  0.739  0.739  0.278  1.0
  Zn  Zn1  1  0.261  0.261  0.778  1.0
  Zn  Zn2  1  0.979  0.577  0.209  1.0
  Zn  Zn3  1  0.021  0.423  0.709  1.0
  Zn  Zn4  1  0.577  0.979  0.209  1.0
  Zn  Zn5  1  0.423  0.021  0.709  1.0
  Cr  Cr6  1  0.150  0.354  0.245  1.0
  Cr  Cr7  1  0.850  0.646  0.745  1.0
  Cr  Cr8  1  0.646  0.850  0.745  1.0
  Cr  Cr9  1  0.354  0.150  0.245  1.0
  O  O10  1  0.352  0.947  0.320  1.0
  O  O11  1  0.648  0.053  0.820  1.0
  O  O12  1  0.053  0.648  0.820  1.0
  O  O13  1  0.947  0.352  0.320  1.0
  O  O14  1  0.546  0.289  0.929  1.0
  O  O15  1  0.454  0.711  0.429  1.0
  O  O16  1  0.711  0.454  0.429  1.0
  O  O17  1  0.289  0.546  0.929  1.0
  O  O18  1  0.997  0.844  0.061  1.0
  O  O19  1  0.003  0.156  0.561  1.0
  O  O20  1  0.362  0.362  0.171  1.0
  O  O21  1  0.638  0.638  0.671  1.0
  O  O22  1  0.844  0.997  0.061  1.0
  O  O23  1  0.156  0.003  0.561  1.0
[/CIF]
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