The structure described by MgCr3(SO4)6 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a 4-coordinate geometry to one O(11), one O(13), one O(17), and one O(19) atom. There are three inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(1), one O(2), one O(4), one O(6), one O(7), and one O(9) atom to form CrO6 octahedra that share  a cornercorner with one S(1)O4 tetrahedra,  a cornercorner with one S(2)O4 tetrahedra,  a cornercorner with one S(3)O4 tetrahedra,  a cornercorner with one S(4)O4 tetrahedra,  a cornercorner with one S(5)O4 tetrahedra, and  a cornercorner with one S(6)O4 tetrahedra. In the second Cr site, Cr(2) is bonded to one O(16), one O(18), one O(19), one O(21), one O(23), and one O(24) atom to form CrO6 octahedra that share  a cornercorner with one S(1)O4 tetrahedra,  a cornercorner with one S(2)O4 tetrahedra,  a cornercorner with one S(3)O4 tetrahedra,  a cornercorner with one S(4)O4 tetrahedra,  a cornercorner with one S(5)O4 tetrahedra, and  a cornercorner with one S(6)O4 tetrahedra. In the third Cr site, Cr(3) is bonded to one O(10), one O(13), one O(14), one O(17), one O(22), and one O(5) atom to form CrO6 octahedra that share  a cornercorner with one S(1)O4 tetrahedra,  a cornercorner with one S(2)O4 tetrahedra,  a cornercorner with one S(3)O4 tetrahedra,  a cornercorner with one S(4)O4 tetrahedra,  a cornercorner with one S(5)O4 tetrahedra, and  a cornercorner with one S(6)O4 tetrahedra. There are six inequivalent S sites. In the first S site, S(1) is bonded to one O(24), one O(3), one O(5), and one O(6) atom to form SO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra, and  a cornercorner with one Cr(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 38-48°. In the second S site, S(2) is bonded to one O(13), one O(21), one O(7), and one O(8) atom to form SO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra, and  a cornercorner with one Cr(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 36-49°. In the third S site, S(3) is bonded to one O(14), one O(15), one O(23), and one O(9) atom to form SO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra, and  a cornercorner with one Cr(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 36-44°. In the fourth S site, S(4) is bonded to one O(10), one O(11), one O(16), and one O(2) atom to form SO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra, and  a cornercorner with one Cr(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 29-45°. In the fifth S site, S(5) is bonded to one O(12), one O(17), one O(18), and one O(4) atom to form SO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra, and  a cornercorner with one Cr(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 28-43°. In the sixth S site, S(6) is bonded to one O(1), one O(19), one O(20), and one O(22) atom to form SO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra, and  a cornercorner with one Cr(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 25-46°. There are twenty-four inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Cr(1) and one S(6) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Cr(1) and one S(4) atom. In the third O site, O(3) is bonded in a single-bond geometry to one S(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Cr(1) and one S(5) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Cr(3) and one S(1) atom. In the sixth O site, O(6) is bonded in a distorted bent 120 degrees geometry to one Cr(1) and one S(1) atom. In the seventh O site, O(7) is bonded in a distorted bent 150 degrees geometry to one Cr(1) and one S(2) atom. In the eighth O site, O(8) is bonded in a single-bond geometry to one S(2) atom. In the ninth O site, O(9) is bonded in a distorted bent 150 degrees geometry to one Cr(1) and one S(3) atom. In the tenth O site, O(10) is bonded in a bent 150 degrees geometry to one Cr(3) and one S(4) atom. In the eleventh O site, O(11) is bonded in a bent 120 degrees geometry to one Mg(1) and one S(4) atom. In the twelfth O site, O(12) is bonded in a single-bond geometry to one S(5) atom. In the thirteenth O site, O(13) is bonded in a distorted trigonal planar geometry to one Mg(1), one Cr(3), and one S(2) atom. In the fourteenth O site, O(14) is bonded in a distorted bent 150 degrees geometry to one Cr(3) and one S(3) atom. In the fifteenth O site, O(15) is bonded in a single-bond geometry to one S(3) atom. In the sixteenth O site, O(16) is bonded in a distorted bent 150 degrees geometry to one Cr(2) and one S(4) atom. In the seventeenth O site, O(17) is bonded in a distorted trigonal planar geometry to one Mg(1), one Cr(3), and one S(5) atom. In the eighteenth O site, O(18) is bonded in a bent 150 degrees geometry to one Cr(2) and one S(5) atom. In the nineteenth O site, O(19) is bonded in a trigonal planar geometry to one Mg(1), one Cr(2), and one S(6) atom. In the twentieth O site, O(20) is bonded in a single-bond geometry to one S(6) atom. In the twenty-first O site, O(21) is bonded in a bent 150 degrees geometry to one Cr(2) and one S(2) atom. In the twenty-second O site, O(22) is bonded in a distorted bent 150 degrees geometry to one Cr(3) and one S(6) atom. In the twenty-third O site, O(23) is bonded in a bent 150 degrees geometry to one Cr(2) and one S(3) atom. In the twenty-fourth O site, O(24) is bonded in a bent 150 degrees geometry to one Cr(2) and one S(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgCr3(SO4)6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.989
_cell_length_b   9.183
_cell_length_c   9.058
_cell_angle_alpha   54.499
_cell_angle_beta   54.424
_cell_angle_gamma   55.443
_symmetry_Int_Tables_number   1
_cell_volume   464.413
_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  0.581  0.227  0.831  1.0
  Cr  Cr1  1  0.350  0.355  0.358  1.0
  Cr  Cr2  1  0.657  0.652  0.639  1.0
  Cr  Cr3  1  0.849  0.836  0.849  1.0
  S  S4  1  0.049  0.729  0.467  1.0
  S  S5  1  0.470  0.027  0.737  1.0
  S  S6  1  0.739  0.469  0.034  1.0
  S  S7  1  0.251  0.567  0.953  1.0
  S  S8  1  0.528  0.960  0.265  1.0
  S  S9  1  0.956  0.253  0.536  1.0
  O  O10  1  0.111  0.275  0.530  1.0
  O  O11  1  0.268  0.534  0.124  1.0
  O  O12  1  0.000  0.920  0.330  1.0
  O  O13  1  0.509  0.128  0.273  1.0
  O  O14  1  0.026  0.718  0.652  1.0
  O  O15  1  0.250  0.598  0.395  1.0
  O  O16  1  0.384  0.225  0.613  1.0
  O  O17  1  0.336  0.958  0.930  1.0
  O  O18  1  0.610  0.382  0.235  1.0
  O  O19  1  0.045  0.677  0.976  1.0
  O  O20  1  0.317  0.384  0.941  1.0
  O  O21  1  0.347  0.950  0.322  1.0
  O  O22  1  0.633  0.043  0.740  1.0
  O  O23  1  0.708  0.656  0.020  1.0
  O  O24  1  0.941  0.348  0.983  1.0
  O  O25  1  0.373  0.682  0.767  1.0
  O  O26  1  0.660  0.982  0.049  1.0
  O  O27  1  0.649  0.777  0.377  1.0
  O  O28  1  0.751  0.388  0.638  1.0
  O  O29  1  0.969  0.293  0.353  1.0
  O  O30  1  0.582  0.905  0.621  1.0
  O  O31  1  0.943  0.062  0.693  1.0
  O  O32  1  0.658  0.509  0.901  1.0
  O  O33  1  0.922  0.628  0.527  1.0
[/CIF]
.
The structure described by MgCr3(SO4)6 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a 4-coordinate geometry to one O(11), one O(13), one O(17), and one O(19) atom. There are three inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(1), one O(2), one O(4), one O(6), one O(7), and one O(9) atom to form CrO6 octahedra that share  a cornercorner with one S(1)O4 tetrahedra,  a cornercorner with one S(2)O4 tetrahedra,  a cornercorner with one S(3)O4 tetrahedra,  a cornercorner with one S(4)O4 tetrahedra,  a cornercorner with one S(5)O4 tetrahedra, and  a cornercorner with one S(6)O4 tetrahedra. In the second Cr site, Cr(2) is bonded to one O(16), one O(18), one O(19), one O(21), one O(23), and one O(24) atom to form CrO6 octahedra that share  a cornercorner with one S(1)O4 tetrahedra,  a cornercorner with one S(2)O4 tetrahedra,  a cornercorner with one S(3)O4 tetrahedra,  a cornercorner with one S(4)O4 tetrahedra,  a cornercorner with one S(5)O4 tetrahedra, and  a cornercorner with one S(6)O4 tetrahedra. In the third Cr site, Cr(3) is bonded to one O(10), one O(13), one O(14), one O(17), one O(22), and one O(5) atom to form CrO6 octahedra that share  a cornercorner with one S(1)O4 tetrahedra,  a cornercorner with one S(2)O4 tetrahedra,  a cornercorner with one S(3)O4 tetrahedra,  a cornercorner with one S(4)O4 tetrahedra,  a cornercorner with one S(5)O4 tetrahedra, and  a cornercorner with one S(6)O4 tetrahedra. There are six inequivalent S sites. In the first S site, S(1) is bonded to one O(24), one O(3), one O(5), and one O(6) atom to form SO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra, and  a cornercorner with one Cr(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 38-48°. In the second S site, S(2) is bonded to one O(13), one O(21), one O(7), and one O(8) atom to form SO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra, and  a cornercorner with one Cr(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 36-49°. In the third S site, S(3) is bonded to one O(14), one O(15), one O(23), and one O(9) atom to form SO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra, and  a cornercorner with one Cr(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 36-44°. In the fourth S site, S(4) is bonded to one O(10), one O(11), one O(16), and one O(2) atom to form SO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra, and  a cornercorner with one Cr(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 29-45°. In the fifth S site, S(5) is bonded to one O(12), one O(17), one O(18), and one O(4) atom to form SO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra, and  a cornercorner with one Cr(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 28-43°. In the sixth S site, S(6) is bonded to one O(1), one O(19), one O(20), and one O(22) atom to form SO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra, and  a cornercorner with one Cr(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 25-46°. There are twenty-four inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Cr(1) and one S(6) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Cr(1) and one S(4) atom. In the third O site, O(3) is bonded in a single-bond geometry to one S(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Cr(1) and one S(5) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Cr(3) and one S(1) atom. In the sixth O site, O(6) is bonded in a distorted bent 120 degrees geometry to one Cr(1) and one S(1) atom. In the seventh O site, O(7) is bonded in a distorted bent 150 degrees geometry to one Cr(1) and one S(2) atom. In the eighth O site, O(8) is bonded in a single-bond geometry to one S(2) atom. In the ninth O site, O(9) is bonded in a distorted bent 150 degrees geometry to one Cr(1) and one S(3) atom. In the tenth O site, O(10) is bonded in a bent 150 degrees geometry to one Cr(3) and one S(4) atom. In the eleventh O site, O(11) is bonded in a bent 120 degrees geometry to one Mg(1) and one S(4) atom. In the twelfth O site, O(12) is bonded in a single-bond geometry to one S(5) atom. In the thirteenth O site, O(13) is bonded in a distorted trigonal planar geometry to one Mg(1), one Cr(3), and one S(2) atom. In the fourteenth O site, O(14) is bonded in a distorted bent 150 degrees geometry to one Cr(3) and one S(3) atom. In the fifteenth O site, O(15) is bonded in a single-bond geometry to one S(3) atom. In the sixteenth O site, O(16) is bonded in a distorted bent 150 degrees geometry to one Cr(2) and one S(4) atom. In the seventeenth O site, O(17) is bonded in a distorted trigonal planar geometry to one Mg(1), one Cr(3), and one S(5) atom. In the eighteenth O site, O(18) is bonded in a bent 150 degrees geometry to one Cr(2) and one S(5) atom. In the nineteenth O site, O(19) is bonded in a trigonal planar geometry to one Mg(1), one Cr(2), and one S(6) atom. In the twentieth O site, O(20) is bonded in a single-bond geometry to one S(6) atom. In the twenty-first O site, O(21) is bonded in a bent 150 degrees geometry to one Cr(2) and one S(2) atom. In the twenty-second O site, O(22) is bonded in a distorted bent 150 degrees geometry to one Cr(3) and one S(6) atom. In the twenty-third O site, O(23) is bonded in a bent 150 degrees geometry to one Cr(2) and one S(3) atom. In the twenty-fourth O site, O(24) is bonded in a bent 150 degrees geometry to one Cr(2) and one S(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgCr3(SO4)6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.989
_cell_length_b   9.183
_cell_length_c   9.058
_cell_angle_alpha   54.499
_cell_angle_beta   54.424
_cell_angle_gamma   55.443
_symmetry_Int_Tables_number   1
_cell_volume   464.413
_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  0.581  0.227  0.831  1.0
  Cr  Cr1  1  0.350  0.355  0.358  1.0
  Cr  Cr2  1  0.657  0.652  0.639  1.0
  Cr  Cr3  1  0.849  0.836  0.849  1.0
  S  S4  1  0.049  0.729  0.467  1.0
  S  S5  1  0.470  0.027  0.737  1.0
  S  S6  1  0.739  0.469  0.034  1.0
  S  S7  1  0.251  0.567  0.953  1.0
  S  S8  1  0.528  0.960  0.265  1.0
  S  S9  1  0.956  0.253  0.536  1.0
  O  O10  1  0.111  0.275  0.530  1.0
  O  O11  1  0.268  0.534  0.124  1.0
  O  O12  1  0.000  0.920  0.330  1.0
  O  O13  1  0.509  0.128  0.273  1.0
  O  O14  1  0.026  0.718  0.652  1.0
  O  O15  1  0.250  0.598  0.395  1.0
  O  O16  1  0.384  0.225  0.613  1.0
  O  O17  1  0.336  0.958  0.930  1.0
  O  O18  1  0.610  0.382  0.235  1.0
  O  O19  1  0.045  0.677  0.976  1.0
  O  O20  1  0.317  0.384  0.941  1.0
  O  O21  1  0.347  0.950  0.322  1.0
  O  O22  1  0.633  0.043  0.740  1.0
  O  O23  1  0.708  0.656  0.020  1.0
  O  O24  1  0.941  0.348  0.983  1.0
  O  O25  1  0.373  0.682  0.767  1.0
  O  O26  1  0.660  0.982  0.049  1.0
  O  O27  1  0.649  0.777  0.377  1.0
  O  O28  1  0.751  0.388  0.638  1.0
  O  O29  1  0.969  0.293  0.353  1.0
  O  O30  1  0.582  0.905  0.621  1.0
  O  O31  1  0.943  0.062  0.693  1.0
  O  O32  1  0.658  0.509  0.901  1.0
  O  O33  1  0.922  0.628  0.527  1.0
[/CIF]
.