The compound described by ZnCr2O4 crystallizes in the monoclinic C2/m space group. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(2), two equivalent O(1), and three equivalent O(3) atoms to form CrO6 octahedra that share corners with four equivalent Cr(2)O6 octahedra, corners with two equivalent Zn(1)O5 square pyramids, edges with four equivalent Cr(1)O6 octahedra, and edges with three equivalent Zn(1)O5 square pyramids. The corner-sharing octahedral tilt angles range from 49-56°. In the second Cr site, Cr(2) is bonded to one O(1), two equivalent O(2), and three equivalent O(4) atoms to form CrO6 octahedra that share corners with four equivalent Cr(1)O6 octahedra, corners with four equivalent Zn(1)O5 square pyramids, edges with four equivalent Cr(2)O6 octahedra, and  a faceface with one Zn(1)O5 square pyramid. The corner-sharing octahedral tilt angles range from 49-56°. Zn(1) is bonded to one O(1), two equivalent O(3), and two equivalent O(4) atoms to form ZnO5 square pyramids that share corners with two equivalent Cr(1)O6 octahedra, corners with four equivalent Cr(2)O6 octahedra, edges with three equivalent Cr(1)O6 octahedra, edges with two equivalent Zn(1)O5 square pyramids, and  a faceface with one Cr(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-57°. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Cr(2), two equivalent Cr(1), and one Zn(1) atom to form OZnCr3 trigonal pyramids that share corners with two equivalent O(3)Zn2Cr3 square pyramids,  a cornercorner with one O(4)Zn2Cr3 trigonal bipyramid, corners with two equivalent O(1)ZnCr3 trigonal pyramids, edges with three equivalent O(3)Zn2Cr3 square pyramids, and edges with two equivalent O(4)Zn2Cr3 trigonal bipyramids. In the second O site, O(2) is bonded in a trigonal planar geometry to one Cr(1) and two equivalent Cr(2) atoms. In the third O site, O(3) is bonded to three equivalent Cr(1) and two equivalent Zn(1) atoms to form OZn2Cr3 square pyramids that share corners with two equivalent O(4)Zn2Cr3 trigonal bipyramids, corners with two equivalent O(1)ZnCr3 trigonal pyramids, edges with four equivalent O(3)Zn2Cr3 square pyramids,  an edgeedge with one O(4)Zn2Cr3 trigonal bipyramid, and edges with three equivalent O(1)ZnCr3 trigonal pyramids. In the fourth O site, O(4) is bonded to three equivalent Cr(2) and two equivalent Zn(1) atoms to form distorted OZn2Cr3 trigonal bipyramids that share corners with two equivalent O(3)Zn2Cr3 square pyramids,  a cornercorner with one O(1)ZnCr3 trigonal pyramid,  an edgeedge with one O(3)Zn2Cr3 square pyramid, edges with four equivalent O(4)Zn2Cr3 trigonal bipyramids, and edges with two equivalent O(1)ZnCr3 trigonal pyramids. is represented by the CIF file [CIF]
data_ZnCr2O4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.358
_cell_length_b   7.358
_cell_length_c   9.476
_cell_angle_alpha   51.128
_cell_angle_beta   51.128
_cell_angle_gamma   23.415
_symmetry_Int_Tables_number   1
_cell_volume   156.507
_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  0.668  0.668  0.316  1.0
  Zn  Zn1  1  0.332  0.332  0.684  1.0
  Cr  Cr2  1  0.364  0.364  0.958  1.0
  Cr  Cr3  1  0.854  0.854  0.313  1.0
  Cr  Cr4  1  0.146  0.146  0.687  1.0
  Cr  Cr5  1  0.636  0.636  0.042  1.0
  O  O6  1  0.138  0.138  0.903  1.0
  O  O7  1  0.537  0.537  0.750  1.0
  O  O8  1  0.463  0.463  0.250  1.0
  O  O9  1  0.862  0.862  0.097  1.0
  O  O10  1  0.831  0.831  0.838  1.0
  O  O11  1  0.212  0.212  0.421  1.0
  O  O12  1  0.169  0.169  0.162  1.0
  O  O13  1  0.788  0.788  0.579  1.0
[/CIF]
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The compound described by ZnCr2O4 crystallizes in the monoclinic C2/m space group. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(2), two equivalent O(1), and three equivalent O(3) atoms to form CrO6 octahedra that share corners with four equivalent Cr(2)O6 octahedra, corners with two equivalent Zn(1)O5 square pyramids, edges with four equivalent Cr(1)O6 octahedra, and edges with three equivalent Zn(1)O5 square pyramids. The corner-sharing octahedral tilt angles range from 49-56°. In the second Cr site, Cr(2) is bonded to one O(1), two equivalent O(2), and three equivalent O(4) atoms to form CrO6 octahedra that share corners with four equivalent Cr(1)O6 octahedra, corners with four equivalent Zn(1)O5 square pyramids, edges with four equivalent Cr(2)O6 octahedra, and  a faceface with one Zn(1)O5 square pyramid. The corner-sharing octahedral tilt angles range from 49-56°. Zn(1) is bonded to one O(1), two equivalent O(3), and two equivalent O(4) atoms to form ZnO5 square pyramids that share corners with two equivalent Cr(1)O6 octahedra, corners with four equivalent Cr(2)O6 octahedra, edges with three equivalent Cr(1)O6 octahedra, edges with two equivalent Zn(1)O5 square pyramids, and  a faceface with one Cr(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-57°. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Cr(2), two equivalent Cr(1), and one Zn(1) atom to form OZnCr3 trigonal pyramids that share corners with two equivalent O(3)Zn2Cr3 square pyramids,  a cornercorner with one O(4)Zn2Cr3 trigonal bipyramid, corners with two equivalent O(1)ZnCr3 trigonal pyramids, edges with three equivalent O(3)Zn2Cr3 square pyramids, and edges with two equivalent O(4)Zn2Cr3 trigonal bipyramids. In the second O site, O(2) is bonded in a trigonal planar geometry to one Cr(1) and two equivalent Cr(2) atoms. In the third O site, O(3) is bonded to three equivalent Cr(1) and two equivalent Zn(1) atoms to form OZn2Cr3 square pyramids that share corners with two equivalent O(4)Zn2Cr3 trigonal bipyramids, corners with two equivalent O(1)ZnCr3 trigonal pyramids, edges with four equivalent O(3)Zn2Cr3 square pyramids,  an edgeedge with one O(4)Zn2Cr3 trigonal bipyramid, and edges with three equivalent O(1)ZnCr3 trigonal pyramids. In the fourth O site, O(4) is bonded to three equivalent Cr(2) and two equivalent Zn(1) atoms to form distorted OZn2Cr3 trigonal bipyramids that share corners with two equivalent O(3)Zn2Cr3 square pyramids,  a cornercorner with one O(1)ZnCr3 trigonal pyramid,  an edgeedge with one O(3)Zn2Cr3 square pyramid, edges with four equivalent O(4)Zn2Cr3 trigonal bipyramids, and edges with two equivalent O(1)ZnCr3 trigonal pyramids. is represented by the CIF file [CIF]
data_ZnCr2O4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.358
_cell_length_b   7.358
_cell_length_c   9.476
_cell_angle_alpha   51.128
_cell_angle_beta   51.128
_cell_angle_gamma   23.415
_symmetry_Int_Tables_number   1
_cell_volume   156.507
_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  0.668  0.668  0.316  1.0
  Zn  Zn1  1  0.332  0.332  0.684  1.0
  Cr  Cr2  1  0.364  0.364  0.958  1.0
  Cr  Cr3  1  0.854  0.854  0.313  1.0
  Cr  Cr4  1  0.146  0.146  0.687  1.0
  Cr  Cr5  1  0.636  0.636  0.042  1.0
  O  O6  1  0.138  0.138  0.903  1.0
  O  O7  1  0.537  0.537  0.750  1.0
  O  O8  1  0.463  0.463  0.250  1.0
  O  O9  1  0.862  0.862  0.097  1.0
  O  O10  1  0.831  0.831  0.838  1.0
  O  O11  1  0.212  0.212  0.421  1.0
  O  O12  1  0.169  0.169  0.162  1.0
  O  O13  1  0.788  0.788  0.579  1.0
[/CIF]
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