The material described by MgCr3AgO8 crystallizes in the monoclinic Cm space group. Mg(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form distorted MgO4 tetrahedra that share corners with three equivalent Cr(1)O6 octahedra, corners with three equivalent Ag(1)O6 octahedra, corners with two equivalent Cr(3)O4 tetrahedra, and  an edgeedge with one Cr(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 59-77°. There are three inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(6) atoms to form CrO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, corners with three equivalent Cr(2)O4 tetrahedra, corners with three equivalent Cr(3)O4 tetrahedra, and edges with two equivalent Ag(1)O6 octahedra. In the second Cr site, Cr(2) is bonded to one O(4), one O(5), and two equivalent O(1) atoms to form CrO4 tetrahedra that share corners with three equivalent Cr(1)O6 octahedra, corners with three equivalent Ag(1)O6 octahedra, and  an edgeedge with one Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 49-63°. In the third Cr site, Cr(3) is bonded to one O(2), one O(3), and two equivalent O(6) atoms to form CrO4 tetrahedra that share corners with three equivalent Cr(1)O6 octahedra, corners with three equivalent Ag(1)O6 octahedra, and corners with two equivalent Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 45-60°. Ag(1) is bonded to one O(2), one O(5), two equivalent O(1), and two equivalent O(6) atoms to form AgO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, corners with three equivalent Cr(2)O4 tetrahedra, corners with three equivalent Cr(3)O4 tetrahedra, and edges with two equivalent Cr(1)O6 octahedra. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Cr(1), one Cr(2), and one Ag(1) atom to form distorted edge-sharing OMgCr2Ag tetrahedra. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Mg(1), one Cr(3), and one Ag(1) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Mg(1), one Cr(1), and one Cr(3) atom. In the fourth O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Cr(1) and one Cr(2) atom. In the fifth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one Cr(2) and one Ag(1) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Cr(1), one Cr(3), and one Ag(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgCr3AgO8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.254
_cell_length_b   5.254
_cell_length_c   6.626
_cell_angle_alpha   89.916
_cell_angle_beta   89.916
_cell_angle_gamma   65.801
_symmetry_Int_Tables_number   1
_cell_volume   166.847
_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  0.336  0.336  0.248  1.0
  Cr  Cr1  1  0.998  0.998  0.496  1.0
  Cr  Cr2  1  0.654  0.654  0.279  1.0
  Cr  Cr3  1  0.357  0.357  0.729  1.0
  Ag  Ag4  1  0.003  0.003  0.987  1.0
  O  O5  1  0.744  0.275  0.284  1.0
  O  O6  1  0.275  0.744  0.284  1.0
  O  O7  1  0.266  0.266  0.959  1.0
  O  O8  1  0.227  0.227  0.516  1.0
  O  O9  1  0.771  0.771  0.478  1.0
  O  O10  1  0.741  0.741  0.061  1.0
  O  O11  1  0.223  0.717  0.705  1.0
  O  O12  1  0.717  0.223  0.705  1.0
[/CIF]
.
The material described by MgCr3AgO8 crystallizes in the monoclinic Cm space group. Mg(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form distorted MgO4 tetrahedra that share corners with three equivalent Cr(1)O6 octahedra, corners with three equivalent Ag(1)O6 octahedra, corners with two equivalent Cr(3)O4 tetrahedra, and  an edgeedge with one Cr(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 59-77°. There are three inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(6) atoms to form CrO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, corners with three equivalent Cr(2)O4 tetrahedra, corners with three equivalent Cr(3)O4 tetrahedra, and edges with two equivalent Ag(1)O6 octahedra. In the second Cr site, Cr(2) is bonded to one O(4), one O(5), and two equivalent O(1) atoms to form CrO4 tetrahedra that share corners with three equivalent Cr(1)O6 octahedra, corners with three equivalent Ag(1)O6 octahedra, and  an edgeedge with one Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 49-63°. In the third Cr site, Cr(3) is bonded to one O(2), one O(3), and two equivalent O(6) atoms to form CrO4 tetrahedra that share corners with three equivalent Cr(1)O6 octahedra, corners with three equivalent Ag(1)O6 octahedra, and corners with two equivalent Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 45-60°. Ag(1) is bonded to one O(2), one O(5), two equivalent O(1), and two equivalent O(6) atoms to form AgO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, corners with three equivalent Cr(2)O4 tetrahedra, corners with three equivalent Cr(3)O4 tetrahedra, and edges with two equivalent Cr(1)O6 octahedra. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Cr(1), one Cr(2), and one Ag(1) atom to form distorted edge-sharing OMgCr2Ag tetrahedra. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Mg(1), one Cr(3), and one Ag(1) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Mg(1), one Cr(1), and one Cr(3) atom. In the fourth O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Cr(1) and one Cr(2) atom. In the fifth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one Cr(2) and one Ag(1) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Cr(1), one Cr(3), and one Ag(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgCr3AgO8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.254
_cell_length_b   5.254
_cell_length_c   6.626
_cell_angle_alpha   89.916
_cell_angle_beta   89.916
_cell_angle_gamma   65.801
_symmetry_Int_Tables_number   1
_cell_volume   166.847
_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  0.336  0.336  0.248  1.0
  Cr  Cr1  1  0.998  0.998  0.496  1.0
  Cr  Cr2  1  0.654  0.654  0.279  1.0
  Cr  Cr3  1  0.357  0.357  0.729  1.0
  Ag  Ag4  1  0.003  0.003  0.987  1.0
  O  O5  1  0.744  0.275  0.284  1.0
  O  O6  1  0.275  0.744  0.284  1.0
  O  O7  1  0.266  0.266  0.959  1.0
  O  O8  1  0.227  0.227  0.516  1.0
  O  O9  1  0.771  0.771  0.478  1.0
  O  O10  1  0.741  0.741  0.061  1.0
  O  O11  1  0.223  0.717  0.705  1.0
  O  O12  1  0.717  0.223  0.705  1.0
[/CIF]
.