The crystal structure described by MgCr2(GeO3)4 crystallizes in the monoclinic C2 space group. Mg(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms to form distorted MgO6 pentagonal pyramids that share corners with four equivalent Ge(1)O4 tetrahedra,  an edgeedge with one Cr(1)O6 octahedra, edges with two equivalent Cr(2)O6 octahedra, and edges with two equivalent Ge(2)O4 tetrahedra. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent O(4), two equivalent O(5), and two equivalent O(6) atoms to form distorted CrO6 octahedra that share corners with two equivalent Ge(2)O4 tetrahedra, corners with four equivalent Ge(1)O4 tetrahedra, edges with two equivalent Cr(2)O6 octahedra, and  an edgeedge with one Mg(1)O6 pentagonal pyramid. In the second Cr site, Cr(2) is bonded to two equivalent O(3), two equivalent O(5), and two equivalent O(6) atoms to form CrO6 octahedra that share corners with two equivalent Ge(1)O4 tetrahedra, corners with four equivalent Ge(2)O4 tetrahedra, edges with two equivalent Cr(1)O6 octahedra, and edges with two equivalent Mg(1)O6 pentagonal pyramids. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded to one O(1), one O(2), one O(4), and one O(5) atom to form GeO4 tetrahedra that share  a cornercorner with one Cr(2)O6 octahedra, corners with two equivalent Cr(1)O6 octahedra, corners with two equivalent Mg(1)O6 pentagonal pyramids, and corners with two equivalent Ge(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 37-63°. In the second Ge site, Ge(2) is bonded to one O(1), one O(2), one O(3), and one O(6) atom to form GeO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra, corners with two equivalent Cr(2)O6 octahedra, corners with two equivalent Ge(1)O4 tetrahedra, and  an edgeedge with one Mg(1)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles range from 35-66°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Ge(1) and one Ge(2) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Mg(1), one Ge(1), and one Ge(2) atom. In the third O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Mg(1), one Cr(2), and one Ge(2) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Cr(1) and one Ge(1) atom. In the fifth O site, O(5) is bonded to one Mg(1), one Cr(1), one Cr(2), and one Ge(1) atom to form a mixture of distorted edge and corner-sharing OMgCr2Ge tetrahedra. In the sixth O site, O(6) is bonded in a trigonal non-coplanar geometry to one Cr(1), one Cr(2), and one Ge(2) atom. is represented by the CIF card [CIF]
data_MgCr2(GeO3)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.513
_cell_length_b   6.809
_cell_length_c   6.812
_cell_angle_alpha   80.751
_cell_angle_beta   73.223
_cell_angle_gamma   73.225
_symmetry_Int_Tables_number   1
_cell_volume   233.586
_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
  Mg  Mg0  1  0.750  0.274  0.726  1.0
  Cr  Cr1  1  0.751  0.907  0.093  1.0
  Cr  Cr2  1  0.251  0.085  0.915  1.0
  Ge  Ge3  1  0.736  0.389  0.201  1.0
  Ge  Ge4  1  0.765  0.798  0.610  1.0
  Ge  Ge5  1  0.246  0.615  0.812  1.0
  Ge  Ge6  1  0.256  0.188  0.385  1.0
  O  O7  1  0.411  0.391  0.334  1.0
  O  O8  1  0.090  0.665  0.609  1.0
  O  O9  1  0.591  0.603  0.683  1.0
  O  O10  1  0.910  0.316  0.397  1.0
  O  O11  1  0.159  0.115  0.649  1.0
  O  O12  1  0.342  0.351  0.885  1.0
  O  O13  1  0.727  0.936  0.380  1.0
  O  O14  1  0.776  0.619  0.063  1.0
  O  O15  1  0.852  0.197  0.018  1.0
  O  O16  1  0.650  0.982  0.803  1.0
  O  O17  1  0.144  0.815  0.977  1.0
  O  O18  1  0.357  0.023  0.184  1.0
[/CIF]
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The crystal structure described by MgCr2(GeO3)4 crystallizes in the monoclinic C2 space group. Mg(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms to form distorted MgO6 pentagonal pyramids that share corners with four equivalent Ge(1)O4 tetrahedra,  an edgeedge with one Cr(1)O6 octahedra, edges with two equivalent Cr(2)O6 octahedra, and edges with two equivalent Ge(2)O4 tetrahedra. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent O(4), two equivalent O(5), and two equivalent O(6) atoms to form distorted CrO6 octahedra that share corners with two equivalent Ge(2)O4 tetrahedra, corners with four equivalent Ge(1)O4 tetrahedra, edges with two equivalent Cr(2)O6 octahedra, and  an edgeedge with one Mg(1)O6 pentagonal pyramid. In the second Cr site, Cr(2) is bonded to two equivalent O(3), two equivalent O(5), and two equivalent O(6) atoms to form CrO6 octahedra that share corners with two equivalent Ge(1)O4 tetrahedra, corners with four equivalent Ge(2)O4 tetrahedra, edges with two equivalent Cr(1)O6 octahedra, and edges with two equivalent Mg(1)O6 pentagonal pyramids. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded to one O(1), one O(2), one O(4), and one O(5) atom to form GeO4 tetrahedra that share  a cornercorner with one Cr(2)O6 octahedra, corners with two equivalent Cr(1)O6 octahedra, corners with two equivalent Mg(1)O6 pentagonal pyramids, and corners with two equivalent Ge(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 37-63°. In the second Ge site, Ge(2) is bonded to one O(1), one O(2), one O(3), and one O(6) atom to form GeO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra, corners with two equivalent Cr(2)O6 octahedra, corners with two equivalent Ge(1)O4 tetrahedra, and  an edgeedge with one Mg(1)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles range from 35-66°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Ge(1) and one Ge(2) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Mg(1), one Ge(1), and one Ge(2) atom. In the third O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Mg(1), one Cr(2), and one Ge(2) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Cr(1) and one Ge(1) atom. In the fifth O site, O(5) is bonded to one Mg(1), one Cr(1), one Cr(2), and one Ge(1) atom to form a mixture of distorted edge and corner-sharing OMgCr2Ge tetrahedra. In the sixth O site, O(6) is bonded in a trigonal non-coplanar geometry to one Cr(1), one Cr(2), and one Ge(2) atom. is represented by the CIF card [CIF]
data_MgCr2(GeO3)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.513
_cell_length_b   6.809
_cell_length_c   6.812
_cell_angle_alpha   80.751
_cell_angle_beta   73.223
_cell_angle_gamma   73.225
_symmetry_Int_Tables_number   1
_cell_volume   233.586
_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
  Mg  Mg0  1  0.750  0.274  0.726  1.0
  Cr  Cr1  1  0.751  0.907  0.093  1.0
  Cr  Cr2  1  0.251  0.085  0.915  1.0
  Ge  Ge3  1  0.736  0.389  0.201  1.0
  Ge  Ge4  1  0.765  0.798  0.610  1.0
  Ge  Ge5  1  0.246  0.615  0.812  1.0
  Ge  Ge6  1  0.256  0.188  0.385  1.0
  O  O7  1  0.411  0.391  0.334  1.0
  O  O8  1  0.090  0.665  0.609  1.0
  O  O9  1  0.591  0.603  0.683  1.0
  O  O10  1  0.910  0.316  0.397  1.0
  O  O11  1  0.159  0.115  0.649  1.0
  O  O12  1  0.342  0.351  0.885  1.0
  O  O13  1  0.727  0.936  0.380  1.0
  O  O14  1  0.776  0.619  0.063  1.0
  O  O15  1  0.852  0.197  0.018  1.0
  O  O16  1  0.650  0.982  0.803  1.0
  O  O17  1  0.144  0.815  0.977  1.0
  O  O18  1  0.357  0.023  0.184  1.0
[/CIF]
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