The crystal structure described by Er3Sn7 crystallizes in the orthorhombic Cmmm space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded to four equivalent Sn(1), four equivalent Sn(2), and four equivalent Sn(3) atoms to form a mixture of face and corner-sharing ErSn12 cuboctahedra. In the second Er site, Er(2) is bonded in a 10-coordinate geometry to two equivalent Sn(2), two equivalent Sn(3), and six equivalent Sn(4) atoms. There are four inequivalent Sn sites. In the first Sn site, Sn(1) is bonded in a square co-planar geometry to four equivalent Er(1), four equivalent Sn(2), and four equivalent Sn(3) atoms. In the second Sn site, Sn(2) is bonded in a 10-coordinate geometry to two equivalent Er(1), two equivalent Er(2), two equivalent Sn(1), and four equivalent Sn(3) atoms. In the third Sn site, Sn(3) is bonded in a 10-coordinate geometry to two equivalent Er(1), two equivalent Er(2), two equivalent Sn(1), and four equivalent Sn(2) atoms. In the fourth Sn site, Sn(4) is bonded in a 8-coordinate geometry to six equivalent Er(2) and two equivalent Sn(4) atoms. is represented by the CIF file [CIF]
data_Er3Sn7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.357
_cell_length_b   4.406
_cell_length_c   13.415
_cell_angle_alpha   90.000
_cell_angle_beta   99.345
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   254.056
_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
  Er  Er0  1  0.000  0.500  0.000  1.0
  Er  Er1  1  0.311  0.000  0.623  1.0
  Er  Er2  1  0.689  0.000  0.377  1.0
  Sn  Sn3  1  0.500  0.000  0.000  1.0
  Sn  Sn4  1  0.403  0.500  0.806  1.0
  Sn  Sn5  1  0.597  0.500  0.194  1.0
  Sn  Sn6  1  0.097  0.000  0.194  1.0
  Sn  Sn7  1  0.903  0.000  0.806  1.0
  Sn  Sn8  1  0.212  0.500  0.424  1.0
  Sn  Sn9  1  0.788  0.500  0.576  1.0
[/CIF]
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The crystal structure described by Er3Sn7 crystallizes in the orthorhombic Cmmm space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded to four equivalent Sn(1), four equivalent Sn(2), and four equivalent Sn(3) atoms to form a mixture of face and corner-sharing ErSn12 cuboctahedra. In the second Er site, Er(2) is bonded in a 10-coordinate geometry to two equivalent Sn(2), two equivalent Sn(3), and six equivalent Sn(4) atoms. There are four inequivalent Sn sites. In the first Sn site, Sn(1) is bonded in a square co-planar geometry to four equivalent Er(1), four equivalent Sn(2), and four equivalent Sn(3) atoms. In the second Sn site, Sn(2) is bonded in a 10-coordinate geometry to two equivalent Er(1), two equivalent Er(2), two equivalent Sn(1), and four equivalent Sn(3) atoms. In the third Sn site, Sn(3) is bonded in a 10-coordinate geometry to two equivalent Er(1), two equivalent Er(2), two equivalent Sn(1), and four equivalent Sn(2) atoms. In the fourth Sn site, Sn(4) is bonded in a 8-coordinate geometry to six equivalent Er(2) and two equivalent Sn(4) atoms. is represented by the CIF file [CIF]
data_Er3Sn7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.357
_cell_length_b   4.406
_cell_length_c   13.415
_cell_angle_alpha   90.000
_cell_angle_beta   99.345
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   254.056
_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
  Er  Er0  1  0.000  0.500  0.000  1.0
  Er  Er1  1  0.311  0.000  0.623  1.0
  Er  Er2  1  0.689  0.000  0.377  1.0
  Sn  Sn3  1  0.500  0.000  0.000  1.0
  Sn  Sn4  1  0.403  0.500  0.806  1.0
  Sn  Sn5  1  0.597  0.500  0.194  1.0
  Sn  Sn6  1  0.097  0.000  0.194  1.0
  Sn  Sn7  1  0.903  0.000  0.806  1.0
  Sn  Sn8  1  0.212  0.500  0.424  1.0
  Sn  Sn9  1  0.788  0.500  0.576  1.0
[/CIF]
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