data_MgGeCSe
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.54
_cell_length_b   4.54
_cell_length_c   4.54
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   MgGeCSe
_chemical_formula_sum   'Mg1 Ge1 C1 Se1'
_cell_volume   66.38
_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
  Mg  Mg2  1  0.82  0.82  0.82  1.0
  Ge  Ge1  1  0.21  0.21  0.21  1.0
  C  C0  1  0.0  0.0  0.0  1.0
  Se  Se3  1  0.61  0.61  0.61  1.0

data_MgGeCSe
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.54
_cell_length_b   4.54
_cell_length_c   11.13
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   MgGeCSe
_chemical_formula_sum   'Mg3 Ge3 C3 Se3'
_cell_volume   199.14
_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
  Mg  Mg0  3  0.0  0.0  0.18  1.0
  Ge  Ge1  3  0.0  0.0  0.79  1.0
  C  C2  3  0.0  0.0  0.0  1.0
  Se  Se3  3  0.0  0.0  0.39  1.0

Mg Ge C Se
Mg Ge C Se 0 3 o o o 0 3 o + o 0 3 + o o 0 3 o o + 0 2 + + + 0 1 + + o 0 1 + o + 0 1 o + + 1 2 o o o 1 2 o o + 1 2 + o o 1 2 o + o 1 3 - o o 1 3 o - o 1 3 o o - 2 3 o - - 2 3 - o - 2 3 - - o 
MgGeCSe crystallizes in the trigonal R3m space group. Mg(1) is bonded in a 2-coordinate geometry to three equivalent Ge(1), one C(1), and one Se(1) atom. All Mg(1)-Ge(1) bond lengths are 2.71 Å. The Mg(1)-C(1) bond length is 2.00 Å. The Mg(1)-Se(1) bond length is 2.38 Å. Ge(1) is bonded to three equivalent Mg(1), one C(1), and three equivalent Se(1) atoms to form distorted edge-sharing GeMg3CSe3 hexagonal pyramids. The Ge(1)-C(1) bond length is 2.38 Å. All Ge(1)-Se(1) bond lengths are 2.71 Å. C(1) is bonded in a distorted linear geometry to one Mg(1) and one Ge(1) atom. Se(1) is bonded in a 1-coordinate geometry to one Mg(1) and three equivalent Ge(1) atoms.