data_YMg2Sn
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.17
_cell_length_b   5.17
_cell_length_c   5.17
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   YMg2Sn
_chemical_formula_sum   'Y1 Mg2 Sn1'
_cell_volume   97.49
_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
  Y  Y3  1  0.0  0.0  0.0  1.0
  Mg  Mg0  1  0.48  0.48  0.48  1.0
  Mg  Mg1  1  0.83  0.83  0.83  1.0
  Sn  Sn2  1  0.65  0.65  0.65  1.0

data_YMg2Sn
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.17
_cell_length_b   5.17
_cell_length_c   12.65
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   YMg2Sn
_chemical_formula_sum   'Y3 Mg6 Sn3'
_cell_volume   292.47
_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
  Y  Y0  3  0.0  0.0  0.0  1.0
  Mg  Mg1  3  0.0  0.0  0.17  1.0
  Mg  Mg2  3  0.0  0.0  0.52  1.0
  Sn  Sn3  3  0.0  0.0  0.35  1.0

Y Mg Mg Sn
Y Mg Mg Sn 0 2 - - - 1 3 o o o 2 3 o o o 
Mg2YSn crystallizes in the trigonal R3m space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a single-bond geometry to one Sn(1) atom. The Mg(1)-Sn(1) bond length is 2.20 Å. In the second Mg site, Mg(2) is bonded in a distorted linear geometry to one Y(1) and one Sn(1) atom. The Mg(2)-Y(1) bond length is 2.20 Å. The Mg(2)-Sn(1) bond length is 2.20 Å. Y(1) is bonded to one Mg(2) and three equivalent Sn(1) atoms to form distorted YMgSn3 trigonal pyramids that share  a cornercorner with one Sn(1)Y3Mg2 trigonal bipyramid and corners with six equivalent Y(1)MgSn3 trigonal pyramids. All Y(1)-Sn(1) bond lengths are 2.99 Å. Sn(1) is bonded to one Mg(1), one Mg(2), and three equivalent Y(1) atoms to form distorted SnY3Mg2 trigonal bipyramids that share corners with six equivalent Sn(1)Y3Mg2 trigonal bipyramids and  a cornercorner with one Y(1)MgSn3 trigonal pyramid.