data_Na2SiGe
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.94
_cell_length_b   4.94
_cell_length_c   4.94
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Na2SiGe
_chemical_formula_sum   'Na2 Si1 Ge1'
_cell_volume   85.0
_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
  Na  Na1  1  0.74  0.74  0.74  1.0
  Na  Na2  1  0.0  0.0  0.0  1.0
  Si  Si3  1  0.49  0.49  0.49  1.0
  Ge  Ge0  1  0.23  0.23  0.23  1.0

data_Na2SiGe
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.94
_cell_length_b   4.94
_cell_length_c   12.09
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Na2SiGe
_chemical_formula_sum   'Na6 Si3 Ge3'
_cell_volume   254.99
_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
  Na  Na0  3  0.0  0.0  0.0  1.0
  Na  Na1  3  0.0  0.0  0.26  1.0
  Si  Si2  3  0.0  0.0  0.51  1.0
  Ge  Ge3  3  0.0  0.0  0.77  1.0

Na Na Si Ge
NaGeNaSi crystallizes in the trigonal R3m space group. The structure consists of one NaGe framework and one NaSi framework. In the NaGe framework, Na(2) is bonded to four equivalent Ge(1) atoms to form distorted corner-sharing NaGe4 tetrahedra. There is one shorter (2.84 Å) and three longer (3.09 Å) Na(2)-Ge(1) bond lengths. Ge(1) is bonded to four equivalent Na(2) atoms to form distorted corner-sharing GeNa4 tetrahedra. In the NaSi framework, Na(1) is bonded to four equivalent Si(1) atoms to form distorted corner-sharing NaSi4 tetrahedra. There are three shorter (3.00 Å) and one longer (3.08 Å) Na(1)-Si(1) bond length. Si(1) is bonded to four equivalent Na(1) atoms to form distorted corner-sharing SiNa4 tetrahedra.