data_Y2AgSe
_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   Y2AgSe
_chemical_formula_sum   'Y2 Ag1 Se1'
_cell_volume   97.75
_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  Y2  1  0.83  0.83  0.83  1.0
  Y  Y3  1  0.66  0.66  0.66  1.0
  Ag  Ag0  1  0.48  0.48  0.48  1.0
  Se  Se1  1  0.0  0.0  0.0  1.0

data_Y2AgSe
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.17
_cell_length_b   5.17
_cell_length_c   12.67
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Y2AgSe
_chemical_formula_sum   'Y6 Ag3 Se3'
_cell_volume   293.26
_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  0.17  1.0
  Y  Y1  3  0.0  0.0  0.34  1.0
  Ag  Ag2  3  0.0  0.0  0.52  1.0
  Se  Se3  3  0.0  0.0  0.0  1.0

Y Y Ag Se
Y2AgSe crystallizes in the trigonal R3m space group. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded in a distorted single-bond geometry to one Y(2), three equivalent Ag(1), and one Se(1) atom. The Y(1)-Y(2) bond length is 2.18 Å. All Y(1)-Ag(1) bond lengths are 2.99 Å. The Y(1)-Se(1) bond length is 2.18 Å. In the second Y site, Y(2) is bonded to one Y(1), one Ag(1), and three equivalent Se(1) atoms to form distorted YYAgSe3 trigonal bipyramids that share corners with six equivalent Y(2)YAgSe3 trigonal bipyramids,  a cornercorner with one Se(1)Y4 trigonal pyramid, and corners with three equivalent Ag(1)Y4 trigonal pyramids. The Y(2)-Ag(1) bond length is 2.18 Å. All Y(2)-Se(1) bond lengths are 2.99 Å. Ag(1) is bonded to one Y(2) and three equivalent Y(1) atoms to form distorted AgY4 trigonal pyramids that share corners with three equivalent Y(2)YAgSe3 trigonal bipyramids, corners with six equivalent Ag(1)Y4 trigonal pyramids, and edges with three equivalent Se(1)Y4 trigonal pyramids. Se(1) is bonded to one Y(1) and three equivalent Y(2) atoms to form distorted SeY4 trigonal pyramids that share  a cornercorner with one Y(2)YAgSe3 trigonal bipyramid, corners with six equivalent Se(1)Y4 trigonal pyramids, and edges with three equivalent Ag(1)Y4 trigonal pyramids.