The compound described by Ba3MgCr2O8 crystallizes in the triclinic P1 space group. There are three inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 10-coordinate geometry to one O(1), one O(6), one O(7), one O(8), two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms. In the second Ba site, Ba(2) is bonded in a 10-coordinate geometry to one O(2), one O(3), one O(4), one O(5), two equivalent O(6), two equivalent O(7), and two equivalent O(8) atoms. In the third Ba site, Ba(3) is bonded in a 12-coordinate geometry to one O(3), one O(4), one O(5), one O(6), one O(7), one O(8), three equivalent O(1), and three equivalent O(2) atoms. Mg(1) is bonded to one O(3), one O(4), one O(5), one O(6), one O(7), and one O(8) atom to form distorted MgO6 octahedra that share  a faceface with one Cr(1)O4 trigonal pyramid and  a faceface with one Cr(2)O4 trigonal pyramid. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(1), one O(6), one O(7), and one O(8) atom to form distorted CrO4 trigonal pyramids that share  a faceface with one Mg(1)O6 octahedra. In the second Cr site, Cr(2) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form distorted CrO4 trigonal pyramids that share  a faceface with one Mg(1)O6 octahedra. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted linear geometry to one Ba(1), three equivalent Ba(3), and one Cr(1) atom. In the second O site, O(2) is bonded in a distorted linear geometry to one Ba(2), three equivalent Ba(3), and one Cr(2) atom. In the third O site, O(3) is bonded in a 6-coordinate geometry to one Ba(2), one Ba(3), two equivalent Ba(1), one Mg(1), and one Cr(2) atom. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one Ba(2), one Ba(3), two equivalent Ba(1), one Mg(1), and one Cr(2) atom. In the fifth O site, O(5) is bonded in a 6-coordinate geometry to one Ba(2), one Ba(3), two equivalent Ba(1), one Mg(1), and one Cr(2) atom. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(3), two equivalent Ba(2), one Mg(1), and one Cr(1) atom. In the seventh O site, O(7) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(3), two equivalent Ba(2), one Mg(1), and one Cr(1) atom. In the eighth O site, O(8) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(3), two equivalent Ba(2), one Mg(1), and one Cr(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ba3MgCr2O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.281
_cell_length_b   8.281
_cell_length_c   8.282
_cell_angle_alpha   41.627
_cell_angle_beta   41.633
_cell_angle_gamma   41.640
_symmetry_Int_Tables_number   1
_cell_volume   226.606
_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
  Ba  Ba0  1  0.795  0.796  0.796  1.0
  Ba  Ba1  1  0.204  0.205  0.205  1.0
  Ba  Ba2  1  0.996  0.010  0.993  1.0
  Mg  Mg3  1  0.500  0.501  0.500  1.0
  Cr  Cr4  1  0.606  0.607  0.607  1.0
  Cr  Cr5  1  0.393  0.393  0.393  1.0
  O  O6  1  0.688  0.672  0.690  1.0
  O  O7  1  0.321  0.306  0.324  1.0
  O  O8  1  0.283  0.283  0.743  1.0
  O  O9  1  0.282  0.743  0.282  1.0
  O  O10  1  0.743  0.283  0.283  1.0
  O  O11  1  0.716  0.258  0.717  1.0
  O  O12  1  0.717  0.717  0.257  1.0
  O  O13  1  0.257  0.717  0.718  1.0
[/CIF]
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The compound described by Ba3MgCr2O8 crystallizes in the triclinic P1 space group. There are three inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 10-coordinate geometry to one O(1), one O(6), one O(7), one O(8), two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms. In the second Ba site, Ba(2) is bonded in a 10-coordinate geometry to one O(2), one O(3), one O(4), one O(5), two equivalent O(6), two equivalent O(7), and two equivalent O(8) atoms. In the third Ba site, Ba(3) is bonded in a 12-coordinate geometry to one O(3), one O(4), one O(5), one O(6), one O(7), one O(8), three equivalent O(1), and three equivalent O(2) atoms. Mg(1) is bonded to one O(3), one O(4), one O(5), one O(6), one O(7), and one O(8) atom to form distorted MgO6 octahedra that share  a faceface with one Cr(1)O4 trigonal pyramid and  a faceface with one Cr(2)O4 trigonal pyramid. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(1), one O(6), one O(7), and one O(8) atom to form distorted CrO4 trigonal pyramids that share  a faceface with one Mg(1)O6 octahedra. In the second Cr site, Cr(2) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form distorted CrO4 trigonal pyramids that share  a faceface with one Mg(1)O6 octahedra. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted linear geometry to one Ba(1), three equivalent Ba(3), and one Cr(1) atom. In the second O site, O(2) is bonded in a distorted linear geometry to one Ba(2), three equivalent Ba(3), and one Cr(2) atom. In the third O site, O(3) is bonded in a 6-coordinate geometry to one Ba(2), one Ba(3), two equivalent Ba(1), one Mg(1), and one Cr(2) atom. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one Ba(2), one Ba(3), two equivalent Ba(1), one Mg(1), and one Cr(2) atom. In the fifth O site, O(5) is bonded in a 6-coordinate geometry to one Ba(2), one Ba(3), two equivalent Ba(1), one Mg(1), and one Cr(2) atom. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(3), two equivalent Ba(2), one Mg(1), and one Cr(1) atom. In the seventh O site, O(7) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(3), two equivalent Ba(2), one Mg(1), and one Cr(1) atom. In the eighth O site, O(8) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(3), two equivalent Ba(2), one Mg(1), and one Cr(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ba3MgCr2O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.281
_cell_length_b   8.281
_cell_length_c   8.282
_cell_angle_alpha   41.627
_cell_angle_beta   41.633
_cell_angle_gamma   41.640
_symmetry_Int_Tables_number   1
_cell_volume   226.606
_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
  Ba  Ba0  1  0.795  0.796  0.796  1.0
  Ba  Ba1  1  0.204  0.205  0.205  1.0
  Ba  Ba2  1  0.996  0.010  0.993  1.0
  Mg  Mg3  1  0.500  0.501  0.500  1.0
  Cr  Cr4  1  0.606  0.607  0.607  1.0
  Cr  Cr5  1  0.393  0.393  0.393  1.0
  O  O6  1  0.688  0.672  0.690  1.0
  O  O7  1  0.321  0.306  0.324  1.0
  O  O8  1  0.283  0.283  0.743  1.0
  O  O9  1  0.282  0.743  0.282  1.0
  O  O10  1  0.743  0.283  0.283  1.0
  O  O11  1  0.716  0.258  0.717  1.0
  O  O12  1  0.717  0.717  0.257  1.0
  O  O13  1  0.257  0.717  0.718  1.0
[/CIF]
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