The material structure described by Mg17Ba2 crystallizes in the trigonal R-3m space group. Ba(1) is bonded in a 19-coordinate geometry to one Mg(2), three equivalent Mg(3), six equivalent Mg(4), and nine equivalent Mg(1) atoms. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to three equivalent Ba(1), one Mg(2), two equivalent Mg(1), two equivalent Mg(3), and four equivalent Mg(4) atoms to form MgBa3Mg9 cuboctahedra that share corners with five equivalent Mg(3)Ba2Mg10 cuboctahedra, corners with ten equivalent Mg(1)Ba3Mg9 cuboctahedra, edges with three equivalent Mg(3)Ba2Mg10 cuboctahedra, edges with five equivalent Mg(1)Ba3Mg9 cuboctahedra, faces with three equivalent Mg(3)Ba2Mg10 cuboctahedra, and faces with seven equivalent Mg(1)Ba3Mg9 cuboctahedra. In the second Mg site, Mg(2) is bonded in a 14-coordinate geometry to one Ba(1), one Mg(2), three equivalent Mg(1), three equivalent Mg(3), and six equivalent Mg(4) atoms. In the third Mg site, Mg(3) is bonded to two equivalent Ba(1), two equivalent Mg(2), four equivalent Mg(1), and four equivalent Mg(4) atoms to form distorted MgBa2Mg10 cuboctahedra that share corners with four equivalent Mg(3)Ba2Mg10 cuboctahedra, corners with ten equivalent Mg(1)Ba3Mg9 cuboctahedra, edges with six equivalent Mg(1)Ba3Mg9 cuboctahedra, faces with four equivalent Mg(3)Ba2Mg10 cuboctahedra, and faces with six equivalent Mg(1)Ba3Mg9 cuboctahedra. In the fourth Mg site, Mg(4) is bonded in a 12-coordinate geometry to two equivalent Ba(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), and four equivalent Mg(1) atoms. is represented by the CIF card [CIF]
data_Ba2Mg17
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.010
_cell_length_b   8.010
_cell_length_c   8.010
_cell_angle_alpha   82.990
_cell_angle_beta   82.990
_cell_angle_gamma   82.990
_symmetry_Int_Tables_number   1
_cell_volume   503.248
_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  0.662  0.662  0.662  1.0
  Ba  Ba1  1  0.338  0.338  0.338  1.0
  Mg  Mg2  1  0.346  0.346  0.847  1.0
  Mg  Mg3  1  0.346  0.847  0.346  1.0
  Mg  Mg4  1  0.097  0.097  0.097  1.0
  Mg  Mg5  1  0.903  0.903  0.903  1.0
  Mg  Mg6  1  0.000  0.000  0.500  1.0
  Mg  Mg7  1  0.500  0.000  0.000  1.0
  Mg  Mg8  1  0.000  0.500  0.000  1.0
  Mg  Mg9  1  0.293  0.707  0.000  1.0
  Mg  Mg10  1  0.000  0.293  0.707  1.0
  Mg  Mg11  1  0.707  0.000  0.293  1.0
  Mg  Mg12  1  0.707  0.293  0.000  1.0
  Mg  Mg13  1  0.000  0.707  0.293  1.0
  Mg  Mg14  1  0.293  0.000  0.707  1.0
  Mg  Mg15  1  0.654  0.153  0.654  1.0
  Mg  Mg16  1  0.654  0.654  0.153  1.0
  Mg  Mg17  1  0.153  0.654  0.654  1.0
  Mg  Mg18  1  0.847  0.346  0.346  1.0
[/CIF]
.
The material structure described by Mg17Ba2 crystallizes in the trigonal R-3m space group. Ba(1) is bonded in a 19-coordinate geometry to one Mg(2), three equivalent Mg(3), six equivalent Mg(4), and nine equivalent Mg(1) atoms. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to three equivalent Ba(1), one Mg(2), two equivalent Mg(1), two equivalent Mg(3), and four equivalent Mg(4) atoms to form MgBa3Mg9 cuboctahedra that share corners with five equivalent Mg(3)Ba2Mg10 cuboctahedra, corners with ten equivalent Mg(1)Ba3Mg9 cuboctahedra, edges with three equivalent Mg(3)Ba2Mg10 cuboctahedra, edges with five equivalent Mg(1)Ba3Mg9 cuboctahedra, faces with three equivalent Mg(3)Ba2Mg10 cuboctahedra, and faces with seven equivalent Mg(1)Ba3Mg9 cuboctahedra. In the second Mg site, Mg(2) is bonded in a 14-coordinate geometry to one Ba(1), one Mg(2), three equivalent Mg(1), three equivalent Mg(3), and six equivalent Mg(4) atoms. In the third Mg site, Mg(3) is bonded to two equivalent Ba(1), two equivalent Mg(2), four equivalent Mg(1), and four equivalent Mg(4) atoms to form distorted MgBa2Mg10 cuboctahedra that share corners with four equivalent Mg(3)Ba2Mg10 cuboctahedra, corners with ten equivalent Mg(1)Ba3Mg9 cuboctahedra, edges with six equivalent Mg(1)Ba3Mg9 cuboctahedra, faces with four equivalent Mg(3)Ba2Mg10 cuboctahedra, and faces with six equivalent Mg(1)Ba3Mg9 cuboctahedra. In the fourth Mg site, Mg(4) is bonded in a 12-coordinate geometry to two equivalent Ba(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), and four equivalent Mg(1) atoms. is represented by the CIF card [CIF]
data_Ba2Mg17
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.010
_cell_length_b   8.010
_cell_length_c   8.010
_cell_angle_alpha   82.990
_cell_angle_beta   82.990
_cell_angle_gamma   82.990
_symmetry_Int_Tables_number   1
_cell_volume   503.248
_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  0.662  0.662  0.662  1.0
  Ba  Ba1  1  0.338  0.338  0.338  1.0
  Mg  Mg2  1  0.346  0.346  0.847  1.0
  Mg  Mg3  1  0.346  0.847  0.346  1.0
  Mg  Mg4  1  0.097  0.097  0.097  1.0
  Mg  Mg5  1  0.903  0.903  0.903  1.0
  Mg  Mg6  1  0.000  0.000  0.500  1.0
  Mg  Mg7  1  0.500  0.000  0.000  1.0
  Mg  Mg8  1  0.000  0.500  0.000  1.0
  Mg  Mg9  1  0.293  0.707  0.000  1.0
  Mg  Mg10  1  0.000  0.293  0.707  1.0
  Mg  Mg11  1  0.707  0.000  0.293  1.0
  Mg  Mg12  1  0.707  0.293  0.000  1.0
  Mg  Mg13  1  0.000  0.707  0.293  1.0
  Mg  Mg14  1  0.293  0.000  0.707  1.0
  Mg  Mg15  1  0.654  0.153  0.654  1.0
  Mg  Mg16  1  0.654  0.654  0.153  1.0
  Mg  Mg17  1  0.153  0.654  0.654  1.0
  Mg  Mg18  1  0.847  0.346  0.346  1.0
[/CIF]
.