data_SrMgNbAl
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.12
_cell_length_b   5.12
_cell_length_c   5.12
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   SrMgNbAl
_chemical_formula_sum   'Sr1 Mg1 Nb1 Al1'
_cell_volume   94.89
_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
  Sr  Sr3  1  0.43  0.43  0.43  1.0
  Mg  Mg1  1  0.0  0.0  0.0  1.0
  Nb  Nb2  1  0.62  0.62  0.62  1.0
  Al  Al0  1  0.81  0.81  0.81  1.0

data_SrMgNbAl
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.12
_cell_length_b   5.12
_cell_length_c   12.54
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   SrMgNbAl
_chemical_formula_sum   'Sr3 Mg3 Nb3 Al3'
_cell_volume   284.68
_cell_formula_units_Z   3
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-y, x-y, z'
  3  '-x+y, -x, z'
  4  '-y, -x, z'
  5  '-x+y, y, z'
  6  'x, x-y, z'
  7  'x+1/3, y+2/3, z+2/3'
  8  '-y+1/3, x-y+2/3, z+2/3'
  9  '-x+y+1/3, -x+2/3, z+2/3'
  10  '-y+1/3, -x+2/3, z+2/3'
  11  '-x+y+1/3, y+2/3, z+2/3'
  12  'x+1/3, x-y+2/3, z+2/3'
  13  'x+2/3, y+1/3, z+1/3'
  14  '-y+2/3, x-y+1/3, z+1/3'
  15  '-x+y+2/3, -x+1/3, z+1/3'
  16  '-y+2/3, -x+1/3, z+1/3'
  17  '-x+y+2/3, y+1/3, z+1/3'
  18  'x+2/3, x-y+1/3, z+1/3'
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
  Sr  Sr0  3  0.0  0.0  0.57  1.0
  Mg  Mg1  3  0.0  0.0  0.0  1.0
  Nb  Nb2  3  0.0  0.0  0.38  1.0
  Al  Al3  3  0.0  0.0  0.19  1.0

Sr Mg Nb Al
SrMgNbAl crystallizes in the trigonal R3m space group. Sr(1) is bonded in a 1-coordinate geometry to three equivalent Mg(1), one Nb(1), and three equivalent Al(1) atoms. All Sr(1)-Mg(1) bond lengths are 3.20 Å. The Sr(1)-Nb(1) bond length is 2.38 Å. All Sr(1)-Al(1) bond lengths are 3.01 Å. Mg(1) is bonded in a 7-coordinate geometry to three equivalent Sr(1), three equivalent Nb(1), and one Al(1) atom. All Mg(1)-Nb(1) bond lengths are 3.01 Å. The Mg(1)-Al(1) bond length is 2.38 Å. Nb(1) is bonded in a 1-coordinate geometry to one Sr(1), three equivalent Mg(1), and one Al(1) atom. The Nb(1)-Al(1) bond length is 2.38 Å. Al(1) is bonded to three equivalent Sr(1), one Mg(1), and one Nb(1) atom to form distorted corner-sharing AlSr3MgNb trigonal bipyramids.