The structure described by CaMg2Al6O12 crystallizes in the hexagonal P-6 space group. Ca(1) is bonded in a 9-coordinate geometry to three equivalent O(1) and six equivalent O(2) atoms. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 6-coordinate geometry to six equivalent O(4) atoms. In the second Mg site, Mg(2) is bonded to six equivalent O(3) atoms to form distorted MgO6 pentagonal pyramids that share corners with six equivalent Al(1)O6 octahedra, corners with six equivalent Al(2)O6 octahedra, edges with three equivalent Al(2)O6 octahedra, and faces with two equivalent Mg(2)O6 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 27-73°. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(1), one O(3), two equivalent O(2), and two equivalent O(4) atoms to form AlO6 octahedra that share corners with four equivalent Al(2)O6 octahedra, corners with two equivalent Mg(2)O6 pentagonal pyramids, edges with two equivalent Al(1)O6 octahedra, and edges with two equivalent Al(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 53-55°. In the second Al site, Al(2) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms to form AlO6 octahedra that share corners with four equivalent Al(1)O6 octahedra, corners with two equivalent Mg(2)O6 pentagonal pyramids, edges with two equivalent Al(1)O6 octahedra, edges with two equivalent Al(2)O6 octahedra, and  an edgeedge with one Mg(2)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles range from 53-55°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Ca(1), one Al(1), and two equivalent Al(2) atoms. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Ca(1), one Al(2), and two equivalent Al(1) atoms. In the third O site, O(3) is bonded to two equivalent Mg(2), one Al(1), and two equivalent Al(2) atoms to form a mixture of distorted corner and edge-sharing OMg2Al3 trigonal bipyramids. In the fourth O site, O(4) is bonded to two equivalent Mg(1), one Al(2), and two equivalent Al(1) atoms to form a mixture of distorted corner and edge-sharing OMg2Al3 trigonal bipyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_CaMg2Al6O12
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.831
_cell_length_b   8.833
_cell_length_c   8.833
_cell_angle_alpha   120.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   191.290
_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
  Ca  Ca0  1  0.750  1.000  1.000  1.0
  Mg  Mg1  1  0.750  0.333  0.667  1.0
  Mg  Mg2  1  0.250  0.667  0.333  1.0
  Al  Al3  1  0.750  0.643  0.656  1.0
  Al  Al4  1  0.750  0.344  0.987  1.0
  Al  Al5  1  0.750  0.013  0.357  1.0
  Al  Al6  1  0.250  0.354  0.345  1.0
  Al  Al7  1  0.250  0.655  0.009  1.0
  Al  Al8  1  0.250  0.991  0.646  1.0
  O  O9  1  0.750  0.109  0.799  1.0
  O  O10  1  0.750  0.201  0.310  1.0
  O  O11  1  0.750  0.690  0.891  1.0
  O  O12  1  0.250  0.898  0.190  1.0
  O  O13  1  0.250  0.810  0.708  1.0
  O  O14  1  0.250  0.292  0.102  1.0
  O  O15  1  0.750  0.533  0.402  1.0
  O  O16  1  0.750  0.598  0.132  1.0
  O  O17  1  0.750  0.868  0.467  1.0
  O  O18  1  0.250  0.469  0.598  1.0
  O  O19  1  0.250  0.402  0.870  1.0
  O  O20  1  0.250  0.130  0.531  1.0
[/CIF]
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The structure described by CaMg2Al6O12 crystallizes in the hexagonal P-6 space group. Ca(1) is bonded in a 9-coordinate geometry to three equivalent O(1) and six equivalent O(2) atoms. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 6-coordinate geometry to six equivalent O(4) atoms. In the second Mg site, Mg(2) is bonded to six equivalent O(3) atoms to form distorted MgO6 pentagonal pyramids that share corners with six equivalent Al(1)O6 octahedra, corners with six equivalent Al(2)O6 octahedra, edges with three equivalent Al(2)O6 octahedra, and faces with two equivalent Mg(2)O6 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 27-73°. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(1), one O(3), two equivalent O(2), and two equivalent O(4) atoms to form AlO6 octahedra that share corners with four equivalent Al(2)O6 octahedra, corners with two equivalent Mg(2)O6 pentagonal pyramids, edges with two equivalent Al(1)O6 octahedra, and edges with two equivalent Al(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 53-55°. In the second Al site, Al(2) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms to form AlO6 octahedra that share corners with four equivalent Al(1)O6 octahedra, corners with two equivalent Mg(2)O6 pentagonal pyramids, edges with two equivalent Al(1)O6 octahedra, edges with two equivalent Al(2)O6 octahedra, and  an edgeedge with one Mg(2)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles range from 53-55°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Ca(1), one Al(1), and two equivalent Al(2) atoms. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Ca(1), one Al(2), and two equivalent Al(1) atoms. In the third O site, O(3) is bonded to two equivalent Mg(2), one Al(1), and two equivalent Al(2) atoms to form a mixture of distorted corner and edge-sharing OMg2Al3 trigonal bipyramids. In the fourth O site, O(4) is bonded to two equivalent Mg(1), one Al(2), and two equivalent Al(1) atoms to form a mixture of distorted corner and edge-sharing OMg2Al3 trigonal bipyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_CaMg2Al6O12
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.831
_cell_length_b   8.833
_cell_length_c   8.833
_cell_angle_alpha   120.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   191.290
_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
  Ca  Ca0  1  0.750  1.000  1.000  1.0
  Mg  Mg1  1  0.750  0.333  0.667  1.0
  Mg  Mg2  1  0.250  0.667  0.333  1.0
  Al  Al3  1  0.750  0.643  0.656  1.0
  Al  Al4  1  0.750  0.344  0.987  1.0
  Al  Al5  1  0.750  0.013  0.357  1.0
  Al  Al6  1  0.250  0.354  0.345  1.0
  Al  Al7  1  0.250  0.655  0.009  1.0
  Al  Al8  1  0.250  0.991  0.646  1.0
  O  O9  1  0.750  0.109  0.799  1.0
  O  O10  1  0.750  0.201  0.310  1.0
  O  O11  1  0.750  0.690  0.891  1.0
  O  O12  1  0.250  0.898  0.190  1.0
  O  O13  1  0.250  0.810  0.708  1.0
  O  O14  1  0.250  0.292  0.102  1.0
  O  O15  1  0.750  0.533  0.402  1.0
  O  O16  1  0.750  0.598  0.132  1.0
  O  O17  1  0.750  0.868  0.467  1.0
  O  O18  1  0.250  0.469  0.598  1.0
  O  O19  1  0.250  0.402  0.870  1.0
  O  O20  1  0.250  0.130  0.531  1.0
[/CIF]
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