The crystal structure described by RbMgCr3O8 crystallizes in the monoclinic Cm space group. Rb(1) is bonded in a 5-coordinate geometry to one O(6), two equivalent O(2), and two equivalent O(5) atoms. Mg(1) is bonded in a rectangular see-saw-like geometry to one O(4), one O(5), and two equivalent O(1) atoms. There are three inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(3), one O(6), and two equivalent O(2) atoms to form corner-sharing CrO4 tetrahedra. The corner-sharing octahedral tilt angles range from 17-37°. In the second Cr site, Cr(2) is bonded to one O(4), one O(5), and two equivalent O(1) atoms to form corner-sharing CrO4 tetrahedra. The corner-sharing octahedral tilt angles range from 13-47°. In the third Cr site, Cr(3) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form corner-sharing CrO6 octahedra. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Mg(1), one Cr(2), and one Cr(3) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Rb(1), one Cr(1), and one Cr(3) atom. In the third O site, O(3) is bonded in a linear geometry to one Cr(1) and one Cr(3) atom. In the fourth O site, O(4) is bonded in a T-shaped geometry to one Mg(1), one Cr(2), and one Cr(3) atom. In the fifth O site, O(5) is bonded in a distorted L-shaped geometry to two equivalent Rb(1), one Mg(1), and one Cr(2) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one Rb(1) and one Cr(1) atom. is represented by the CIF card [CIF]
data_RbMgCr3O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.473
_cell_length_b   5.473
_cell_length_c   8.816
_cell_angle_alpha   80.255
_cell_angle_beta   80.255
_cell_angle_gamma   60.811
_symmetry_Int_Tables_number   1
_cell_volume   226.069
_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
  Rb  Rb0  1  0.088  0.088  0.044  1.0
  Mg  Mg1  1  0.858  0.858  0.774  1.0
  Cr  Cr2  1  0.377  0.377  0.303  1.0
  Cr  Cr3  1  0.603  0.603  0.686  1.0
  Cr  Cr4  1  0.995  0.995  0.490  1.0
  O  O5  1  0.770  0.233  0.669  1.0
  O  O6  1  0.720  0.226  0.333  1.0
  O  O7  1  0.226  0.720  0.333  1.0
  O  O8  1  0.233  0.770  0.669  1.0
  O  O9  1  0.214  0.214  0.415  1.0
  O  O10  1  0.784  0.784  0.571  1.0
  O  O11  1  0.658  0.658  0.873  1.0
  O  O12  1  0.361  0.361  0.121  1.0
[/CIF]
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The crystal structure described by RbMgCr3O8 crystallizes in the monoclinic Cm space group. Rb(1) is bonded in a 5-coordinate geometry to one O(6), two equivalent O(2), and two equivalent O(5) atoms. Mg(1) is bonded in a rectangular see-saw-like geometry to one O(4), one O(5), and two equivalent O(1) atoms. There are three inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(3), one O(6), and two equivalent O(2) atoms to form corner-sharing CrO4 tetrahedra. The corner-sharing octahedral tilt angles range from 17-37°. In the second Cr site, Cr(2) is bonded to one O(4), one O(5), and two equivalent O(1) atoms to form corner-sharing CrO4 tetrahedra. The corner-sharing octahedral tilt angles range from 13-47°. In the third Cr site, Cr(3) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form corner-sharing CrO6 octahedra. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Mg(1), one Cr(2), and one Cr(3) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Rb(1), one Cr(1), and one Cr(3) atom. In the third O site, O(3) is bonded in a linear geometry to one Cr(1) and one Cr(3) atom. In the fourth O site, O(4) is bonded in a T-shaped geometry to one Mg(1), one Cr(2), and one Cr(3) atom. In the fifth O site, O(5) is bonded in a distorted L-shaped geometry to two equivalent Rb(1), one Mg(1), and one Cr(2) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one Rb(1) and one Cr(1) atom. is represented by the CIF card [CIF]
data_RbMgCr3O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.473
_cell_length_b   5.473
_cell_length_c   8.816
_cell_angle_alpha   80.255
_cell_angle_beta   80.255
_cell_angle_gamma   60.811
_symmetry_Int_Tables_number   1
_cell_volume   226.069
_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
  Rb  Rb0  1  0.088  0.088  0.044  1.0
  Mg  Mg1  1  0.858  0.858  0.774  1.0
  Cr  Cr2  1  0.377  0.377  0.303  1.0
  Cr  Cr3  1  0.603  0.603  0.686  1.0
  Cr  Cr4  1  0.995  0.995  0.490  1.0
  O  O5  1  0.770  0.233  0.669  1.0
  O  O6  1  0.720  0.226  0.333  1.0
  O  O7  1  0.226  0.720  0.333  1.0
  O  O8  1  0.233  0.770  0.669  1.0
  O  O9  1  0.214  0.214  0.415  1.0
  O  O10  1  0.784  0.784  0.571  1.0
  O  O11  1  0.658  0.658  0.873  1.0
  O  O12  1  0.361  0.361  0.121  1.0
[/CIF]
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