The material described by ZnCr2O4 is Spinel-like structured and crystallizes in the trigonal R3m space group. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(2) and three equivalent O(1) atoms to form CrO4 tetrahedra that share corners with three equivalent Zn(2)O6 octahedra and corners with nine equivalent Cr(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-60°. In the second Cr site, Cr(2) is bonded to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms to form CrO6 octahedra that share corners with three equivalent Cr(1)O4 tetrahedra, corners with three equivalent Zn(1)O4 tetrahedra, edges with two equivalent Zn(2)O6 octahedra, and edges with four equivalent Cr(2)O6 octahedra. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to one O(3) and three equivalent O(4) atoms to form ZnO4 tetrahedra that share corners with three equivalent Zn(2)O6 octahedra and corners with nine equivalent Cr(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-60°. In the second Zn site, Zn(2) is bonded to three equivalent O(1) and three equivalent O(4) atoms to form ZnO6 octahedra that share corners with three equivalent Cr(1)O4 tetrahedra, corners with three equivalent Zn(1)O4 tetrahedra, and edges with six equivalent Cr(2)O6 octahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Cr(1), two equivalent Cr(2), and one Zn(2) atom. In the second O site, O(2) is bonded to one Cr(1) and three equivalent Cr(2) atoms to form distorted corner-sharing OCr4 trigonal pyramids. In the third O site, O(3) is bonded to three equivalent Cr(2) and one Zn(1) atom to form distorted corner-sharing OZnCr3 trigonal pyramids. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to two equivalent Cr(2), one Zn(1), and one Zn(2) atom. is represented by the CIF file [CIF]
data_ZnCr2O4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.056
_cell_length_b   6.056
_cell_length_c   6.056
_cell_angle_alpha   59.386
_cell_angle_beta   59.386
_cell_angle_gamma   59.386
_symmetry_Int_Tables_number   1
_cell_volume   154.861
_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  0.003  0.003  0.003  1.0
  Zn  Zn1  1  0.627  0.627  0.627  1.0
  Cr  Cr2  1  0.245  0.245  0.245  1.0
  Cr  Cr3  1  0.626  0.626  0.122  1.0
  Cr  Cr4  1  0.122  0.626  0.626  1.0
  Cr  Cr5  1  0.626  0.122  0.626  1.0
  O  O6  1  0.375  0.852  0.375  1.0
  O  O7  1  0.852  0.375  0.375  1.0
  O  O8  1  0.375  0.375  0.852  1.0
  O  O9  1  0.386  0.386  0.386  1.0
  O  O10  1  0.864  0.864  0.864  1.0
  O  O11  1  0.871  0.871  0.407  1.0
  O  O12  1  0.407  0.871  0.871  1.0
  O  O13  1  0.871  0.407  0.871  1.0
[/CIF]
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The material described by ZnCr2O4 is Spinel-like structured and crystallizes in the trigonal R3m space group. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(2) and three equivalent O(1) atoms to form CrO4 tetrahedra that share corners with three equivalent Zn(2)O6 octahedra and corners with nine equivalent Cr(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-60°. In the second Cr site, Cr(2) is bonded to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms to form CrO6 octahedra that share corners with three equivalent Cr(1)O4 tetrahedra, corners with three equivalent Zn(1)O4 tetrahedra, edges with two equivalent Zn(2)O6 octahedra, and edges with four equivalent Cr(2)O6 octahedra. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to one O(3) and three equivalent O(4) atoms to form ZnO4 tetrahedra that share corners with three equivalent Zn(2)O6 octahedra and corners with nine equivalent Cr(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-60°. In the second Zn site, Zn(2) is bonded to three equivalent O(1) and three equivalent O(4) atoms to form ZnO6 octahedra that share corners with three equivalent Cr(1)O4 tetrahedra, corners with three equivalent Zn(1)O4 tetrahedra, and edges with six equivalent Cr(2)O6 octahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Cr(1), two equivalent Cr(2), and one Zn(2) atom. In the second O site, O(2) is bonded to one Cr(1) and three equivalent Cr(2) atoms to form distorted corner-sharing OCr4 trigonal pyramids. In the third O site, O(3) is bonded to three equivalent Cr(2) and one Zn(1) atom to form distorted corner-sharing OZnCr3 trigonal pyramids. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to two equivalent Cr(2), one Zn(1), and one Zn(2) atom. is represented by the CIF file [CIF]
data_ZnCr2O4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.056
_cell_length_b   6.056
_cell_length_c   6.056
_cell_angle_alpha   59.386
_cell_angle_beta   59.386
_cell_angle_gamma   59.386
_symmetry_Int_Tables_number   1
_cell_volume   154.861
_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  0.003  0.003  0.003  1.0
  Zn  Zn1  1  0.627  0.627  0.627  1.0
  Cr  Cr2  1  0.245  0.245  0.245  1.0
  Cr  Cr3  1  0.626  0.626  0.122  1.0
  Cr  Cr4  1  0.122  0.626  0.626  1.0
  Cr  Cr5  1  0.626  0.122  0.626  1.0
  O  O6  1  0.375  0.852  0.375  1.0
  O  O7  1  0.852  0.375  0.375  1.0
  O  O8  1  0.375  0.375  0.852  1.0
  O  O9  1  0.386  0.386  0.386  1.0
  O  O10  1  0.864  0.864  0.864  1.0
  O  O11  1  0.871  0.871  0.407  1.0
  O  O12  1  0.407  0.871  0.871  1.0
  O  O13  1  0.871  0.407  0.871  1.0
[/CIF]
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