data_Sr3C
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.29
_cell_length_b   6.29
_cell_length_c   6.29
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Sr3C
_chemical_formula_sum   'Sr6 C2'
_cell_volume   249.22
_cell_formula_units_Z   2
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  Sr2  1  0.57  0.0  0.15  1.0
  Sr  Sr3  1  0.72  0.0  0.15  1.0
  Sr  Sr4  1  0.15  0.57  0.0  1.0
  Sr  Sr5  1  0.15  0.72  0.0  1.0
  Sr  Sr6  1  0.0  0.15  0.72  1.0
  Sr  Sr7  1  0.0  0.15  0.57  1.0
  C  C0  1  0.15  0.15  0.15  1.0
  C  C1  1  0.0  0.0  0.0  1.0

data_Sr3C
_symmetry_space_group_name_H-M   R3
_cell_length_a   8.9
_cell_length_b   8.9
_cell_length_c   10.9
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   146
_chemical_formula_structural   Sr3C
_chemical_formula_sum   'Sr18 C6'
_cell_volume   747.65
_cell_formula_units_Z   6
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  'x+1/3, y+2/3, z+2/3'
  5  '-y+1/3, x-y+2/3, z+2/3'
  6  '-x+y+1/3, -x+2/3, z+2/3'
  7  'x+2/3, y+1/3, z+1/3'
  8  '-y+2/3, x-y+1/3, z+1/3'
  9  '-x+y+2/3, -x+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  9  0.0  0.43  0.57  1.0
  Sr  Sr1  9  0.04  0.24  0.96  1.0
  C  C2  3  0.0  0.0  0.0  1.0
  C  C3  3  0.0  0.0  0.15  1.0

Sr Sr Sr Sr Sr Sr C C
Sr Sr Sr Sr Sr Sr C C 0 1 o o o 1 7 + o o 2 3 o o o 3 7 o + o 4 5 o o o 4 7 o o + 6 7 o o o 
Sr3C crystallizes in the trigonal R3 space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a distorted bent 150 degrees geometry to one Sr(2) and one C(1) atom. The Sr(1)-Sr(2) bond length is 0.92 Å. The Sr(1)-C(1) bond length is 2.84 Å. In the second Sr site, Sr(2) is bonded in a distorted single-bond geometry to one Sr(1) and one C(2) atom. The Sr(2)-C(2) bond length is 1.99 Å. There are two inequivalent C sites. In the first C site, C(1) is bonded in a tetrahedral geometry to three equivalent Sr(1) and one C(2) atom. The C(1)-C(2) bond length is 1.60 Å. In the second C site, C(2) is bonded in a distorted tetrahedral geometry to three equivalent Sr(2) and one C(1) atom.