The material described by MgHo2Cr2O8 crystallizes in the monoclinic C2 space group. Mg(1) is bonded to two equivalent O(2) and two equivalent O(4) atoms to form MgO4 tetrahedra that share corners with two equivalent Cr(2)O6 octahedra, corners with two equivalent Ho(2)O6 pentagonal pyramids, and  an edgeedge with one Cr(1)O6 octahedra. The corner-sharing octahedral tilt angles are 54°. There are two inequivalent Ho sites. In the first Ho site, Ho(1) is bonded in a 6-coordinate geometry to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms. In the second Ho site, Ho(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted HoO6 pentagonal pyramids that share corners with two equivalent Cr(2)O6 octahedra, corners with two equivalent Mg(1)O4 tetrahedra, edges with two equivalent Cr(1)O6 octahedra, and edges with two equivalent Cr(2)O6 octahedra. The corner-sharing octahedral tilt angles are 38°. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form CrO6 octahedra that share edges with two equivalent Cr(2)O6 octahedra, edges with two equivalent Ho(2)O6 pentagonal pyramids, and  an edgeedge with one Mg(1)O4 tetrahedra. In the second Cr site, Cr(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted CrO6 octahedra that share corners with two equivalent Ho(2)O6 pentagonal pyramids, corners with two equivalent Mg(1)O4 tetrahedra, edges with two equivalent Cr(1)O6 octahedra, and edges with two equivalent Ho(2)O6 pentagonal pyramids. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Ho(1), one Ho(2), one Cr(1), and one Cr(2) atom to form a mixture of distorted edge and corner-sharing OHo2Cr2 trigonal pyramids. In the second O site, O(2) is bonded in a trigonal non-coplanar geometry to one Mg(1), one Ho(2), and one Cr(2) atom. In the third O site, O(3) is bonded to one Ho(1), one Ho(2), one Cr(1), and one Cr(2) atom to form a mixture of distorted edge and corner-sharing OHo2Cr2 trigonal pyramids. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one Mg(1), one Ho(1), and one Cr(1) atom. is represented by the CIF file [CIF]
data_Ho2MgCr2O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.130
_cell_length_b   5.019
_cell_length_c   7.884
_cell_angle_alpha   105.047
_cell_angle_beta   105.570
_cell_angle_gamma   100.357
_symmetry_Int_Tables_number   1
_cell_volume   181.917
_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
  Ho  Ho0  1  0.346  0.096  0.691  1.0
  Ho  Ho1  1  0.671  0.922  0.343  1.0
  Mg  Mg2  1  0.017  0.767  0.034  1.0
  Cr  Cr3  1  0.821  0.571  0.642  1.0
  Cr  Cr4  1  0.183  0.433  0.366  1.0
  O  O5  1  0.020  0.296  0.570  1.0
  O  O6  1  0.267  0.595  0.190  1.0
  O  O7  1  0.923  0.095  0.190  1.0
  O  O8  1  0.550  0.774  0.570  1.0
  O  O9  1  0.463  0.249  0.448  1.0
  O  O10  1  0.122  0.860  0.829  1.0
  O  O11  1  0.708  0.469  0.829  1.0
  O  O12  1  0.984  0.699  0.448  1.0
[/CIF]
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The material described by MgHo2Cr2O8 crystallizes in the monoclinic C2 space group. Mg(1) is bonded to two equivalent O(2) and two equivalent O(4) atoms to form MgO4 tetrahedra that share corners with two equivalent Cr(2)O6 octahedra, corners with two equivalent Ho(2)O6 pentagonal pyramids, and  an edgeedge with one Cr(1)O6 octahedra. The corner-sharing octahedral tilt angles are 54°. There are two inequivalent Ho sites. In the first Ho site, Ho(1) is bonded in a 6-coordinate geometry to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms. In the second Ho site, Ho(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted HoO6 pentagonal pyramids that share corners with two equivalent Cr(2)O6 octahedra, corners with two equivalent Mg(1)O4 tetrahedra, edges with two equivalent Cr(1)O6 octahedra, and edges with two equivalent Cr(2)O6 octahedra. The corner-sharing octahedral tilt angles are 38°. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form CrO6 octahedra that share edges with two equivalent Cr(2)O6 octahedra, edges with two equivalent Ho(2)O6 pentagonal pyramids, and  an edgeedge with one Mg(1)O4 tetrahedra. In the second Cr site, Cr(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted CrO6 octahedra that share corners with two equivalent Ho(2)O6 pentagonal pyramids, corners with two equivalent Mg(1)O4 tetrahedra, edges with two equivalent Cr(1)O6 octahedra, and edges with two equivalent Ho(2)O6 pentagonal pyramids. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Ho(1), one Ho(2), one Cr(1), and one Cr(2) atom to form a mixture of distorted edge and corner-sharing OHo2Cr2 trigonal pyramids. In the second O site, O(2) is bonded in a trigonal non-coplanar geometry to one Mg(1), one Ho(2), and one Cr(2) atom. In the third O site, O(3) is bonded to one Ho(1), one Ho(2), one Cr(1), and one Cr(2) atom to form a mixture of distorted edge and corner-sharing OHo2Cr2 trigonal pyramids. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one Mg(1), one Ho(1), and one Cr(1) atom. is represented by the CIF file [CIF]
data_Ho2MgCr2O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.130
_cell_length_b   5.019
_cell_length_c   7.884
_cell_angle_alpha   105.047
_cell_angle_beta   105.570
_cell_angle_gamma   100.357
_symmetry_Int_Tables_number   1
_cell_volume   181.917
_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
  Ho  Ho0  1  0.346  0.096  0.691  1.0
  Ho  Ho1  1  0.671  0.922  0.343  1.0
  Mg  Mg2  1  0.017  0.767  0.034  1.0
  Cr  Cr3  1  0.821  0.571  0.642  1.0
  Cr  Cr4  1  0.183  0.433  0.366  1.0
  O  O5  1  0.020  0.296  0.570  1.0
  O  O6  1  0.267  0.595  0.190  1.0
  O  O7  1  0.923  0.095  0.190  1.0
  O  O8  1  0.550  0.774  0.570  1.0
  O  O9  1  0.463  0.249  0.448  1.0
  O  O10  1  0.122  0.860  0.829  1.0
  O  O11  1  0.708  0.469  0.829  1.0
  O  O12  1  0.984  0.699  0.448  1.0
[/CIF]
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