The structure described by SmB4 crystallizes in the tetragonal P4/mbm space group. Sm(1) is bonded in a 18-coordinate geometry to four equivalent B(2), six equivalent B(3), and eight equivalent B(1) atoms. There are three inequivalent B sites. In the first B site, B(2) is bonded in a 9-coordinate geometry to four equivalent Sm(1), one B(2), and four equivalent B(1) atoms. In the second B site, B(1) is bonded in a 9-coordinate geometry to four equivalent Sm(1), one B(3), two equivalent B(1), and two equivalent B(2) atoms. In the third B site, B(3) is bonded in a distorted trigonal planar geometry to six equivalent Sm(1), one B(3), and two equivalent B(1) atoms. is represented by the CIF file [CIF]
data_SmB4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.079
_cell_length_b   7.185
_cell_length_c   7.185
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   210.537
_cell_formula_units_Z   4
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
  Sm  Sm0  1  0.000  0.683  0.183  1.0
  Sm  Sm1  1  0.000  0.817  0.683  1.0
  Sm  Sm2  1  0.000  0.183  0.317  1.0
  Sm  Sm3  1  0.000  0.317  0.817  1.0
  B  B4  1  0.500  0.461  0.325  1.0
  B  B5  1  0.500  0.539  0.675  1.0
  B  B6  1  0.500  0.325  0.539  1.0
  B  B7  1  0.500  0.675  0.461  1.0
  B  B8  1  0.204  0.000  0.000  1.0
  B  B9  1  0.796  0.500  0.500  1.0
  B  B10  1  0.796  0.000  0.000  1.0
  B  B11  1  0.204  0.500  0.500  1.0
  B  B12  1  0.500  0.088  0.588  1.0
  B  B13  1  0.500  0.412  0.088  1.0
  B  B14  1  0.500  0.588  0.912  1.0
  B  B15  1  0.500  0.912  0.412  1.0
  B  B16  1  0.500  0.175  0.039  1.0
  B  B17  1  0.500  0.961  0.175  1.0
  B  B18  1  0.500  0.039  0.825  1.0
  B  B19  1  0.500  0.825  0.961  1.0
[/CIF]
.
The structure described by SmB4 crystallizes in the tetragonal P4/mbm space group. Sm(1) is bonded in a 18-coordinate geometry to four equivalent B(2), six equivalent B(3), and eight equivalent B(1) atoms. There are three inequivalent B sites. In the first B site, B(2) is bonded in a 9-coordinate geometry to four equivalent Sm(1), one B(2), and four equivalent B(1) atoms. In the second B site, B(1) is bonded in a 9-coordinate geometry to four equivalent Sm(1), one B(3), two equivalent B(1), and two equivalent B(2) atoms. In the third B site, B(3) is bonded in a distorted trigonal planar geometry to six equivalent Sm(1), one B(3), and two equivalent B(1) atoms. is represented by the CIF file [CIF]
data_SmB4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.079
_cell_length_b   7.185
_cell_length_c   7.185
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   210.537
_cell_formula_units_Z   4
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
  Sm  Sm0  1  0.000  0.683  0.183  1.0
  Sm  Sm1  1  0.000  0.817  0.683  1.0
  Sm  Sm2  1  0.000  0.183  0.317  1.0
  Sm  Sm3  1  0.000  0.317  0.817  1.0
  B  B4  1  0.500  0.461  0.325  1.0
  B  B5  1  0.500  0.539  0.675  1.0
  B  B6  1  0.500  0.325  0.539  1.0
  B  B7  1  0.500  0.675  0.461  1.0
  B  B8  1  0.204  0.000  0.000  1.0
  B  B9  1  0.796  0.500  0.500  1.0
  B  B10  1  0.796  0.000  0.000  1.0
  B  B11  1  0.204  0.500  0.500  1.0
  B  B12  1  0.500  0.088  0.588  1.0
  B  B13  1  0.500  0.412  0.088  1.0
  B  B14  1  0.500  0.588  0.912  1.0
  B  B15  1  0.500  0.912  0.412  1.0
  B  B16  1  0.500  0.175  0.039  1.0
  B  B17  1  0.500  0.961  0.175  1.0
  B  B18  1  0.500  0.039  0.825  1.0
  B  B19  1  0.500  0.825  0.961  1.0
[/CIF]
.