The structure described by MgCr3(SO4)6 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a distorted hexagonal planar geometry to one O(16), one O(18), one O(19), one O(6), one O(7), and one O(9) 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 31-47°. 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 31-47°. 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 30-47°. 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 30-45°. 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 30-45°. 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 30-44°. 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 trigonal planar geometry to one Mg(1), one Cr(1), and one S(1) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Mg(1), 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 3-coordinate geometry to one Mg(1), 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 single-bond geometry to 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 bent 150 degrees geometry to one Cr(3) and one S(2) atom. In the fourteenth O site, O(14) is bonded in a 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 3-coordinate geometry to one Mg(1), one Cr(2), and one S(4) atom. In the seventeenth O site, O(17) is bonded in a bent 150 degrees geometry to one Cr(3) and one S(5) atom. In the eighteenth O site, O(18) is bonded in a distorted trigonal planar geometry to one Mg(1), one Cr(2), and one S(5) atom. In the nineteenth O site, O(19) is bonded in a 3-coordinate 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 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 CIF card [CIF]
data_MgCr3(SO4)6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.690
_cell_length_b   8.660
_cell_length_c   8.673
_cell_angle_alpha   58.356
_cell_angle_beta   58.387
_cell_angle_gamma   58.346
_symmetry_Int_Tables_number   1
_cell_volume   444.182
_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  0.491  0.514  0.492  1.0
  Cr  Cr1  1  0.353  0.353  0.353  1.0
  Cr  Cr2  1  0.646  0.644  0.646  1.0
  Cr  Cr3  1  0.857  0.857  0.857  1.0
  S  S4  1  0.040  0.744  0.475  1.0
  S  S5  1  0.476  0.043  0.741  1.0
  S  S6  1  0.742  0.475  0.043  1.0
  S  S7  1  0.251  0.529  0.955  1.0
  S  S8  1  0.531  0.954  0.250  1.0
  S  S9  1  0.956  0.251  0.532  1.0
  O  O10  1  0.100  0.315  0.503  1.0
  O  O11  1  0.317  0.501  0.098  1.0
  O  O12  1  0.012  0.932  0.332  1.0
  O  O13  1  0.501  0.097  0.317  1.0
  O  O14  1  0.030  0.729  0.660  1.0
  O  O15  1  0.246  0.600  0.411  1.0
  O  O16  1  0.413  0.248  0.598  1.0
  O  O17  1  0.333  0.012  0.929  1.0
  O  O18  1  0.597  0.414  0.248  1.0
  O  O19  1  0.064  0.693  0.974  1.0
  O  O20  1  0.246  0.359  0.969  1.0
  O  O21  1  0.362  0.966  0.246  1.0
  O  O22  1  0.661  0.030  0.728  1.0
  O  O23  1  0.730  0.660  0.032  1.0
  O  O24  1  0.929  0.330  0.015  1.0
  O  O25  1  0.395  0.601  0.749  1.0
  O  O26  1  0.695  0.974  0.064  1.0
  O  O27  1  0.602  0.747  0.395  1.0
  O  O28  1  0.752  0.393  0.605  1.0
  O  O29  1  0.969  0.249  0.361  1.0
  O  O30  1  0.517  0.906  0.657  1.0
  O  O31  1  0.976  0.062  0.694  1.0
  O  O32  1  0.656  0.520  0.907  1.0
  O  O33  1  0.906  0.658  0.517  1.0
[/CIF]
.
The structure described by MgCr3(SO4)6 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a distorted hexagonal planar geometry to one O(16), one O(18), one O(19), one O(6), one O(7), and one O(9) 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 31-47°. 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 31-47°. 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 30-47°. 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 30-45°. 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 30-45°. 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 30-44°. 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 trigonal planar geometry to one Mg(1), one Cr(1), and one S(1) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Mg(1), 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 3-coordinate geometry to one Mg(1), 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 single-bond geometry to 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 bent 150 degrees geometry to one Cr(3) and one S(2) atom. In the fourteenth O site, O(14) is bonded in a 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 3-coordinate geometry to one Mg(1), one Cr(2), and one S(4) atom. In the seventeenth O site, O(17) is bonded in a bent 150 degrees geometry to one Cr(3) and one S(5) atom. In the eighteenth O site, O(18) is bonded in a distorted trigonal planar geometry to one Mg(1), one Cr(2), and one S(5) atom. In the nineteenth O site, O(19) is bonded in a 3-coordinate 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 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 CIF card [CIF]
data_MgCr3(SO4)6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.690
_cell_length_b   8.660
_cell_length_c   8.673
_cell_angle_alpha   58.356
_cell_angle_beta   58.387
_cell_angle_gamma   58.346
_symmetry_Int_Tables_number   1
_cell_volume   444.182
_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  0.491  0.514  0.492  1.0
  Cr  Cr1  1  0.353  0.353  0.353  1.0
  Cr  Cr2  1  0.646  0.644  0.646  1.0
  Cr  Cr3  1  0.857  0.857  0.857  1.0
  S  S4  1  0.040  0.744  0.475  1.0
  S  S5  1  0.476  0.043  0.741  1.0
  S  S6  1  0.742  0.475  0.043  1.0
  S  S7  1  0.251  0.529  0.955  1.0
  S  S8  1  0.531  0.954  0.250  1.0
  S  S9  1  0.956  0.251  0.532  1.0
  O  O10  1  0.100  0.315  0.503  1.0
  O  O11  1  0.317  0.501  0.098  1.0
  O  O12  1  0.012  0.932  0.332  1.0
  O  O13  1  0.501  0.097  0.317  1.0
  O  O14  1  0.030  0.729  0.660  1.0
  O  O15  1  0.246  0.600  0.411  1.0
  O  O16  1  0.413  0.248  0.598  1.0
  O  O17  1  0.333  0.012  0.929  1.0
  O  O18  1  0.597  0.414  0.248  1.0
  O  O19  1  0.064  0.693  0.974  1.0
  O  O20  1  0.246  0.359  0.969  1.0
  O  O21  1  0.362  0.966  0.246  1.0
  O  O22  1  0.661  0.030  0.728  1.0
  O  O23  1  0.730  0.660  0.032  1.0
  O  O24  1  0.929  0.330  0.015  1.0
  O  O25  1  0.395  0.601  0.749  1.0
  O  O26  1  0.695  0.974  0.064  1.0
  O  O27  1  0.602  0.747  0.395  1.0
  O  O28  1  0.752  0.393  0.605  1.0
  O  O29  1  0.969  0.249  0.361  1.0
  O  O30  1  0.517  0.906  0.657  1.0
  O  O31  1  0.976  0.062  0.694  1.0
  O  O32  1  0.656  0.520  0.907  1.0
  O  O33  1  0.906  0.658  0.517  1.0
[/CIF]
.