data_HfC3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.85
_cell_length_b   3.85
_cell_length_c   3.85
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   HfC3
_chemical_formula_sum   'Hf1 C3'
_cell_volume   40.31
_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
  Hf  Hf3  1  0.72  0.72  0.72  1.0
  C  C0  1  0.08  0.08  0.08  1.0
  C  C1  1  0.0  0.0  0.0  1.0
  C  C2  1  0.36  0.36  0.36  1.0

data_HfC3
_symmetry_space_group_name_H-M   R3m
_cell_length_a   3.85
_cell_length_b   3.85
_cell_length_c   9.43
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   HfC3
_chemical_formula_sum   'Hf3 C9'
_cell_volume   120.93
_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
  Hf  Hf0  3  0.0  0.0  0.28  1.0
  C  C1  3  0.0  0.0  0.0  1.0
  C  C2  3  0.0  0.0  0.64  1.0
  C  C3  3  0.0  0.0  0.92  1.0

Hf C C C
HfC3 crystallizes in the trigonal R3m space group. Hf(1) is bonded in a 10-coordinate geometry to three equivalent C(1), three equivalent C(3), and four equivalent C(2) atoms. All Hf(1)-C(1) bond lengths are 2.24 Å. All Hf(1)-C(3) bond lengths are 2.24 Å. There are three shorter (2.28 Å) and one longer (2.63 Å) Hf(1)-C(2) bond length. There are three inequivalent C sites. In the first C site, C(1) is bonded in a distorted single-bond geometry to three equivalent Hf(1) and one C(2) atom. The C(1)-C(2) bond length is 0.77 Å. In the second C site, C(2) is bonded in a distorted single-bond geometry to four equivalent Hf(1) and one C(1) atom. In the third C site, C(3) is bonded in a trigonal planar geometry to three equivalent Hf(1) atoms.