data_FeSiP4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.92
_cell_length_b   4.92
_cell_length_c   4.92
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   FeSiP4
_chemical_formula_sum   'Fe1 Si1 P4'
_cell_volume   84.02
_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
  Fe  Fe0  1  0.21  0.21  0.21  1.0
  Si  Si5  1  0.0  0.0  0.0  1.0
  P  P1  1  0.35  0.6  0.35  1.0
  P  P2  1  0.6  0.35  0.35  1.0
  P  P3  1  0.6  0.6  0.6  1.0
  P  P4  1  0.35  0.35  0.6  1.0

data_FeSiP4
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.92
_cell_length_b   4.92
_cell_length_c   12.04
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   FeSiP4
_chemical_formula_sum   'Fe3 Si3 P12'
_cell_volume   252.07
_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
  Fe  Fe0  3  0.0  0.0  0.79  1.0
  Si  Si1  3  0.0  0.0  0.0  1.0
  P  P2  9  0.08  0.16  0.56  1.0
  P  P3  3  0.0  0.0  0.4  1.0

Fe Si P P P P
FeSiP4 crystallizes in the trigonal R3m space group. Fe(1) is bonded in a 10-coordinate geometry to one Si(1), three equivalent P(2), and six equivalent P(1) atoms. The Fe(1)-Si(1) bond length is 2.58 Å. All Fe(1)-P(2) bond lengths are 2.90 Å. There are three shorter (2.53 Å) and three longer (2.75 Å) Fe(1)-P(1) bond lengths. Si(1) is bonded in a 3-coordinate geometry to one Fe(1), three equivalent P(1), and three equivalent P(2) atoms. All Si(1)-P(1) bond lengths are 2.47 Å. All Si(1)-P(2) bond lengths are 2.95 Å. There are two inequivalent P sites. In the first P site, P(2) is bonded in a 9-coordinate geometry to three equivalent Fe(1), three equivalent Si(1), and three equivalent P(1) atoms. All P(2)-P(1) bond lengths are 2.09 Å. In the second P site, P(1) is bonded in a 6-coordinate geometry to two equivalent Fe(1), one Si(1), one P(2), and two equivalent P(1) atoms. Both P(1)-P(1) bond lengths are 1.21 Å.