The structure described by BaMg6AlO8 is Caswellsilverite-derived structured and crystallizes in the tetragonal P4/mmm space group. Ba(1) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form BaO6 octahedra that share corners with two equivalent Mg(2)O6 octahedra, corners with four equivalent Ba(1)O6 octahedra, edges with four equivalent Al(1)O6 octahedra, and edges with eight equivalent Mg(3)O6 octahedra. The corner-sharing octahedra are not tilted. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent O(1) and four equivalent O(4) atoms to form MgO6 octahedra that share corners with two equivalent Al(1)O6 octahedra, corners with four equivalent Mg(1)O6 octahedra, edges with four equivalent Mg(2)O6 octahedra, and edges with eight equivalent Mg(3)O6 octahedra. The corner-sharing octahedra are not tilted. In the second Mg site, Mg(2) is bonded to two equivalent O(2) and four equivalent O(4) atoms to form MgO6 octahedra that share corners with two equivalent Ba(1)O6 octahedra, corners with four equivalent Mg(2)O6 octahedra, edges with four equivalent Mg(1)O6 octahedra, and edges with eight equivalent Mg(3)O6 octahedra. The corner-sharing octahedra are not tilted. In the third Mg site, Mg(3) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form MgO6 octahedra that share corners with six equivalent Mg(3)O6 octahedra, edges with two equivalent Ba(1)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra, edges with two equivalent Al(1)O6 octahedra, and edges with four equivalent Mg(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-9°. Al(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form AlO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with four equivalent Al(1)O6 octahedra, edges with four equivalent Ba(1)O6 octahedra, and edges with eight equivalent Mg(3)O6 octahedra. The corner-sharing octahedra are not tilted. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), four equivalent Mg(3), and one Al(1) atom to form OMg5Al octahedra that share corners with six equivalent O(1)Mg5Al octahedra, edges with four equivalent O(3)Ba2Mg2Al2 octahedra, edges with four equivalent O(2)BaMg5 octahedra, and edges with four equivalent O(4)Mg6 octahedra. The corner-sharing octahedral tilt angles range from 0-9°. In the second O site, O(2) is bonded to one Ba(1), one Mg(2), and four equivalent Mg(3) atoms to form OBaMg5 octahedra that share corners with six equivalent O(2)BaMg5 octahedra, edges with four equivalent O(3)Ba2Mg2Al2 octahedra, edges with four equivalent O(1)Mg5Al octahedra, and edges with four equivalent O(4)Mg6 octahedra. The corner-sharing octahedral tilt angles range from 0-7°. In the third O site, O(3) is bonded to two equivalent Ba(1), two equivalent Mg(3), and two equivalent Al(1) atoms to form OBa2Mg2Al2 octahedra that share corners with two equivalent O(4)Mg6 octahedra, corners with four equivalent O(3)Ba2Mg2Al2 octahedra, edges with four equivalent O(3)Ba2Mg2Al2 octahedra, edges with four equivalent O(2)BaMg5 octahedra, and edges with four equivalent O(1)Mg5Al octahedra. The corner-sharing octahedra are not tilted. In the fourth O site, O(4) is bonded to two equivalent Mg(1), two equivalent Mg(2), and two equivalent Mg(3) atoms to form OMg6 octahedra that share corners with two equivalent O(3)Ba2Mg2Al2 octahedra, corners with four equivalent O(4)Mg6 octahedra, edges with four equivalent O(2)BaMg5 octahedra, edges with four equivalent O(1)Mg5Al octahedra, and edges with four equivalent O(4)Mg6 octahedra. The corner-sharing octahedra are not tilted. is represented by the Crystallographic Information File (CIF) [CIF]
data_BaMg6AlO8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.831
_cell_length_b   4.693
_cell_length_c   4.693
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   194.507
_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  0.000  0.500  0.500  1.0
  Mg  Mg1  1  0.500  0.000  0.000  1.0
  Mg  Mg2  1  0.500  0.500  0.500  1.0
  Mg  Mg3  1  0.266  0.000  0.500  1.0
  Mg  Mg4  1  0.734  0.000  0.500  1.0
  Mg  Mg5  1  0.266  0.500  0.000  1.0
  Mg  Mg6  1  0.734  0.500  0.000  1.0
  Al  Al7  1  0.000  0.000  0.000  1.0
  O  O8  1  0.245  0.000  0.000  1.0
  O  O9  1  0.755  0.000  0.000  1.0
  O  O10  1  0.282  0.500  0.500  1.0
  O  O11  1  0.718  0.500  0.500  1.0
  O  O12  1  0.000  0.000  0.500  1.0
  O  O13  1  0.500  0.000  0.500  1.0
  O  O14  1  0.000  0.500  0.000  1.0
  O  O15  1  0.500  0.500  0.000  1.0
[/CIF]
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The structure described by BaMg6AlO8 is Caswellsilverite-derived structured and crystallizes in the tetragonal P4/mmm space group. Ba(1) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form BaO6 octahedra that share corners with two equivalent Mg(2)O6 octahedra, corners with four equivalent Ba(1)O6 octahedra, edges with four equivalent Al(1)O6 octahedra, and edges with eight equivalent Mg(3)O6 octahedra. The corner-sharing octahedra are not tilted. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent O(1) and four equivalent O(4) atoms to form MgO6 octahedra that share corners with two equivalent Al(1)O6 octahedra, corners with four equivalent Mg(1)O6 octahedra, edges with four equivalent Mg(2)O6 octahedra, and edges with eight equivalent Mg(3)O6 octahedra. The corner-sharing octahedra are not tilted. In the second Mg site, Mg(2) is bonded to two equivalent O(2) and four equivalent O(4) atoms to form MgO6 octahedra that share corners with two equivalent Ba(1)O6 octahedra, corners with four equivalent Mg(2)O6 octahedra, edges with four equivalent Mg(1)O6 octahedra, and edges with eight equivalent Mg(3)O6 octahedra. The corner-sharing octahedra are not tilted. In the third Mg site, Mg(3) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form MgO6 octahedra that share corners with six equivalent Mg(3)O6 octahedra, edges with two equivalent Ba(1)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra, edges with two equivalent Al(1)O6 octahedra, and edges with four equivalent Mg(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-9°. Al(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form AlO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with four equivalent Al(1)O6 octahedra, edges with four equivalent Ba(1)O6 octahedra, and edges with eight equivalent Mg(3)O6 octahedra. The corner-sharing octahedra are not tilted. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), four equivalent Mg(3), and one Al(1) atom to form OMg5Al octahedra that share corners with six equivalent O(1)Mg5Al octahedra, edges with four equivalent O(3)Ba2Mg2Al2 octahedra, edges with four equivalent O(2)BaMg5 octahedra, and edges with four equivalent O(4)Mg6 octahedra. The corner-sharing octahedral tilt angles range from 0-9°. In the second O site, O(2) is bonded to one Ba(1), one Mg(2), and four equivalent Mg(3) atoms to form OBaMg5 octahedra that share corners with six equivalent O(2)BaMg5 octahedra, edges with four equivalent O(3)Ba2Mg2Al2 octahedra, edges with four equivalent O(1)Mg5Al octahedra, and edges with four equivalent O(4)Mg6 octahedra. The corner-sharing octahedral tilt angles range from 0-7°. In the third O site, O(3) is bonded to two equivalent Ba(1), two equivalent Mg(3), and two equivalent Al(1) atoms to form OBa2Mg2Al2 octahedra that share corners with two equivalent O(4)Mg6 octahedra, corners with four equivalent O(3)Ba2Mg2Al2 octahedra, edges with four equivalent O(3)Ba2Mg2Al2 octahedra, edges with four equivalent O(2)BaMg5 octahedra, and edges with four equivalent O(1)Mg5Al octahedra. The corner-sharing octahedra are not tilted. In the fourth O site, O(4) is bonded to two equivalent Mg(1), two equivalent Mg(2), and two equivalent Mg(3) atoms to form OMg6 octahedra that share corners with two equivalent O(3)Ba2Mg2Al2 octahedra, corners with four equivalent O(4)Mg6 octahedra, edges with four equivalent O(2)BaMg5 octahedra, edges with four equivalent O(1)Mg5Al octahedra, and edges with four equivalent O(4)Mg6 octahedra. The corner-sharing octahedra are not tilted. is represented by the Crystallographic Information File (CIF) [CIF]
data_BaMg6AlO8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.831
_cell_length_b   4.693
_cell_length_c   4.693
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   194.507
_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  0.000  0.500  0.500  1.0
  Mg  Mg1  1  0.500  0.000  0.000  1.0
  Mg  Mg2  1  0.500  0.500  0.500  1.0
  Mg  Mg3  1  0.266  0.000  0.500  1.0
  Mg  Mg4  1  0.734  0.000  0.500  1.0
  Mg  Mg5  1  0.266  0.500  0.000  1.0
  Mg  Mg6  1  0.734  0.500  0.000  1.0
  Al  Al7  1  0.000  0.000  0.000  1.0
  O  O8  1  0.245  0.000  0.000  1.0
  O  O9  1  0.755  0.000  0.000  1.0
  O  O10  1  0.282  0.500  0.500  1.0
  O  O11  1  0.718  0.500  0.500  1.0
  O  O12  1  0.000  0.000  0.500  1.0
  O  O13  1  0.500  0.000  0.500  1.0
  O  O14  1  0.000  0.500  0.000  1.0
  O  O15  1  0.500  0.500  0.000  1.0
[/CIF]
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