data_Er2Se3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   14.32
_cell_length_b   14.32
_cell_length_c   14.32
_cell_angle_alpha   144.89
_cell_angle_beta   144.89
_cell_angle_gamma   50.5
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Er2Se3
_chemical_formula_sum   'Er16 Se24'
_cell_volume   965.86
_cell_formula_units_Z   8
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  0.24  0.16  0.46  1.0
  Er  Er1  1  0.0  0.0  0.32  1.0
  Er  Er2  1  0.99  0.16  0.19  1.0
  Er  Er3  1  0.24  0.16  0.02  1.0
  Er  Er4  1  0.0  0.32  0.16  1.0
  Er  Er5  1  0.07  0.16  0.97  1.0
  Er  Er6  1  0.33  0.16  0.24  1.0
  Er  Er7  1  0.16  0.93  0.93  1.0
  Er  Er8  1  0.16  0.01  0.71  1.0
  Er  Er9  1  0.0  0.32  0.79  1.0
  Er  Er10  1  0.16  0.31  0.76  1.0
  Er  Er11  1  0.16  0.39  0.98  1.0
  Er  Er12  1  0.0  0.0  0.58  1.0
  Er  Er13  1  0.84  0.07  0.49  1.0
  Er  Er14  1  0.07  0.16  0.41  1.0
  Er  Er15  1  0.48  0.24  0.54  1.0
  Se  Se16  1  0.9  0.4  0.75  1.0
  Se  Se17  1  0.56  0.87  0.78  1.0
  Se  Se18  1  0.44  0.76  0.78  1.0
  Se  Se19  1  0.56  0.08  0.7  1.0
  Se  Se20  1  0.44  0.55  0.7  1.0
  Se  Se21  1  0.73  0.6  0.75  1.0
  Se  Se22  1  0.73  0.72  0.73  1.0
  Se  Se23  1  0.53  0.64  0.55  1.0
  Se  Se24  1  1.0  0.53  0.45  1.0
  Se  Se25  1  0.58  0.6  0.68  1.0
  Se  Se26  1  0.32  0.79  0.4  1.0
  Se  Se27  1  0.92  0.73  0.27  1.0
  Se  Se28  1  0.4  0.58  0.22  1.0
  Se  Se29  1  0.79  0.68  0.5  1.0
  Se  Se30  1  0.76  0.76  0.25  1.0
  Se  Se31  1  0.55  0.76  0.17  1.0
  Se  Se32  1  0.92  0.58  0.2  1.0
  Se  Se33  1  0.24  0.88  0.25  1.0
  Se  Se34  1  1.0  0.79  0.02  1.0
  Se  Se35  1  0.72  0.42  0.2  1.0
  Se  Se36  1  0.32  0.53  0.97  1.0
  Se  Se37  1  0.45  0.88  0.17  1.0
  Se  Se38  1  0.79  0.64  0.98  1.0
  Se  Se39  1  0.53  0.68  0.93  1.0

data_Er2Se3
_symmetry_space_group_name_H-M   P1
_cell_length_a   8.64
_cell_length_b   8.64
_cell_length_c   14.32
_cell_angle_alpha   107.55
_cell_angle_beta   107.55
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Er2Se3
_chemical_formula_sum   'Er16 Se24'
_cell_volume   965.86
_cell_formula_units_Z   8
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  0.14  0.16  0.39  1.0
  Er  Er1  1  0.16  0.32  0.16  1.0
  Er  Er2  1  0.19  0.16  0.27  1.0
  Er  Er3  1  0.3  0.01  0.46  1.0
  Er  Er4  1  0.41  0.39  0.57  1.0
  Er  Er5  1  0.42  0.0  0.42  1.0
  Er  Er6  1  0.53  0.32  0.53  1.0
  Er  Er7  1  0.55  0.31  0.71  1.0
  Er  Er8  1  0.58  0.07  0.42  1.0
  Er  Er9  1  0.68  0.0  0.68  1.0
  Er  Er10  1  0.7  0.16  0.95  1.0
  Er  Er11  1  0.7  0.24  0.18  1.0
  Er  Er12  1  0.75  0.16  0.82  1.0
  Er  Er13  1  0.92  0.16  0.25  1.0
  Er  Er14  1  0.97  0.16  0.96  1.0
  Er  Er15  1  0.99  0.93  0.15  1.0
  Se  Se16  1  0.08  0.53  0.08  1.0
  Se  Se17  1  0.09  0.64  0.62  1.0
  Se  Se18  1  0.09  0.87  0.65  1.0
  Se  Se19  1  0.18  0.68  0.97  1.0
  Se  Se20  1  0.21  0.42  0.93  1.0
  Se  Se21  1  0.36  0.58  0.76  1.0
  Se  Se22  1  0.38  0.58  0.3  1.0
  Se  Se23  1  0.38  0.79  0.7  1.0
  Se  Se24  1  0.39  0.08  0.95  1.0
  Se  Se25  1  0.46  0.73  0.38  1.0
  Se  Se26  1  0.5  0.76  0.27  1.0
  Se  Se27  1  0.56  0.53  0.88  1.0
  Se  Se28  1  0.59  0.76  0.14  1.0
  Se  Se29  1  0.63  0.88  0.86  1.0
  Se  Se30  1  0.65  0.4  0.56  1.0
  Se  Se31  1  0.66  0.64  0.45  1.0
  Se  Se32  1  0.71  0.88  0.16  1.0
  Se  Se33  1  0.75  0.68  0.29  1.0
  Se  Se34  1  0.76  0.79  0.76  1.0
  Se  Se35  1  0.85  0.6  0.59  1.0
  Se  Se36  1  0.86  0.55  0.3  1.0
  Se  Se37  1  0.92  0.6  0.5  1.0
  Se  Se38  1  0.98  0.76  0.42  1.0
  Se  Se39  1  0.99  0.72  0.72  1.0

Er Er Er Er Er Er Er Er Er Er Er Er Er Er Er Er Se Se Se Se Se Se Se Se Se Se Se Se Se Se Se Se Se Se Se Se Se Se Se Se
Er2Se3 crystallizes in the triclinic P1 space group. There are sixteen inequivalent Er sites. In the first Er site, Er(1) is bonded in a 1-coordinate geometry to one Er(15), one Er(3), one Se(18), and one Se(4) atom. The Er(1)-Er(15) bond length is 1.91 Å. The Er(1)-Er(3) bond length is 2.27 Å. The Er(1)-Se(18) bond length is 2.34 Å. The Er(1)-Se(4) bond length is 2.82 Å. In the second Er site, Er(2) is bonded in a distorted single-bond geometry to one Er(15), one Se(11), one Se(19), and one Se(23) atom. The Er(2)-Er(15) bond length is 1.97 Å. The Er(2)-Se(11) bond length is 3.30 Å. The Er(2)-Se(19) bond length is 2.45 Å. The Er(2)-Se(23) bond length is 3.83 Å. In the third Er site, Er(3) is bonded in a 7-coordinate geometry to one Er(1), one Er(15), one Er(5), one Se(19), one Se(20), one Se(4), and one Se(9) atom. The Er(3)-Er(15) bond length is 2.31 Å. The Er(3)-Er(5) bond length is 2.71 Å. The Er(3)-Se(19) bond length is 3.62 Å. The Er(3)-Se(20) bond length is 3.26 Å. The Er(3)-Se(4) bond length is 3.70 Å. The Er(3)-Se(9) bond length is 3.14 Å. In the fourth Er site, Er(4) is bonded in a 3-coordinate geometry to one Er(6), one Er(7), and one Er(9) atom. The Er(4)-Er(6) bond length is 1.88 Å. The Er(4)-Er(7) bond length is 2.28 Å. The Er(4)-Er(9) bond length is 2.10 Å. In the fifth Er site, Er(5) is bonded in a 2-coordinate geometry to one Er(3), one Er(6), one Se(17), and one Se(9) atom. The Er(5)-Er(6) bond length is 2.31 Å. The Er(5)-Se(17) bond length is 2.79 Å. The Er(5)-Se(9) bond length is 2.45 Å. In the sixth Er site, Er(6) is bonded in a 4-coordinate geometry to one Er(4), one Er(5), one Er(7), and one Er(8) atom. The Er(6)-Er(7) bond length is 2.28 Å. The Er(6)-Er(8) bond length is 2.47 Å. In the seventh Er site, Er(7) is bonded in a 6-coordinate geometry to one Er(16), one Er(4), one Er(6), one Er(8), one Se(22), and one Se(5) atom. The Er(7)-Er(16) bond length is 2.10 Å. The Er(7)-Er(8) bond length is 2.27 Å. The Er(7)-Se(22) bond length is 2.74 Å. The Er(7)-Se(5) bond length is 3.35 Å. In the eighth Er site, Er(8) is bonded in a 1-coordinate geometry to one Er(6), one Er(7), one Se(14), and one Se(22) atom. The Er(8)-Se(14) bond length is 3.65 Å. The Er(8)-Se(22) bond length is 2.49 Å. In the ninth Er site, Er(9) is bonded in a 1-coordinate geometry to one Er(13), one Er(4), and one Se(3) atom. The Er(9)-Er(13) bond length is 1.31 Å. The Er(9)-Se(3) bond length is 3.26 Å. In the tenth Er site, Er(10) is bonded in a single-bond geometry to one Er(12) and one Se(1) atom. The Er(10)-Er(12) bond length is 1.38 Å. The Er(10)-Se(1) bond length is 1.20 Å. In the eleventh Er site, Er(11) is bonded in a distorted single-bond geometry to one Er(15), one Se(13), and one Se(21) atom. The Er(11)-Er(15) bond length is 2.68 Å. The Er(11)-Se(13) bond length is 2.91 Å. The Er(11)-Se(21) bond length is 2.61 Å. In the twelfth Er site, Er(12) is bonded in a 1-coordinate geometry to one Er(10), one Se(11), one Se(13), and one Se(8) atom. The Er(12)-Se(11) bond length is 3.42 Å. The Er(12)-Se(13) bond length is 2.95 Å. The Er(12)-Se(8) bond length is 3.60 Å. In the thirteenth Er site, Er(13) is bonded in a 3-coordinate geometry to one Er(14), one Er(9), one Se(12), and one Se(15) atom. The Er(13)-Er(14) bond length is 1.53 Å. The Er(13)-Se(12) bond length is 2.26 Å. The Er(13)-Se(15) bond length is 2.81 Å. In the fourteenth Er site, Er(14) is bonded in a 1-coordinate geometry to one Er(13) and one Se(15) atom. The Er(14)-Se(15) bond length is 2.92 Å. In the fifteenth Er site, Er(15) is bonded in a 7-coordinate geometry to one Er(1), one Er(11), one Er(2), one Er(3), one Se(18), one Se(19), and one Se(21) atom. The Er(15)-Se(18) bond length is 2.89 Å. The Er(15)-Se(19) bond length is 3.08 Å. The Er(15)-Se(21) bond length is 3.60 Å. In the sixteenth Er site, Er(16) is bonded in a 4-coordinate geometry to one Er(7), one Se(22), one Se(4), and one Se(5) atom. The Er(16)-Se(22) bond length is 3.06 Å. The Er(16)-Se(4) bond length is 3.47 Å. The Er(16)-Se(5) bond length is 2.79 Å. There are twenty-four inequivalent Se sites. In the first Se site, Se(1) is bonded in a single-bond geometry to one Er(10) and one Se(23) atom. The Se(1)-Se(23) bond length is 2.95 Å. In the second Se site, Se(2) is bonded in a 1-coordinate geometry to one Se(11), one Se(7), and one Se(8) atom. The Se(2)-Se(11) bond length is 2.57 Å. The Se(2)-Se(7) bond length is 2.21 Å. The Se(2)-Se(8) bond length is 1.94 Å. In the third Se site, Se(3) is bonded in a 4-coordinate geometry to one Er(9), one Se(10), one Se(24), and one Se(5) atom. The Se(3)-Se(10) bond length is 2.27 Å. The Se(3)-Se(24) bond length is 2.25 Å. The Se(3)-Se(5) bond length is 2.12 Å. In the fourth Se site, Se(4) is bonded in a 1-coordinate geometry to one Er(1), one Er(16), and one Er(3) atom. In the fifth Se site, Se(5) is bonded in a 2-coordinate geometry to one Er(16), one Er(7), one Se(24), and one Se(3) atom. The Se(5)-Se(24) bond length is 1.44 Å. In the sixth Se site, Se(6) is bonded in a 1-coordinate geometry to one Se(10), one Se(23), one Se(7), and one Se(8) atom. The Se(6)-Se(10) bond length is 1.46 Å. The Se(6)-Se(23) bond length is 2.32 Å. The Se(6)-Se(7) bond length is 1.93 Å. The Se(6)-Se(8) bond length is 1.95 Å. In the seventh Se site, Se(7) is bonded in a distorted trigonal pyramidal geometry to one Se(19), one Se(2), one Se(6), and one Se(8) atom. The Se(7)-Se(19) bond length is 2.22 Å. The Se(7)-Se(8) bond length is 1.89 Å. In the eighth Se site, Se(8) is bonded in a 7-coordinate geometry to one Er(12), one Se(10), one Se(11), one Se(13), one Se(2), one Se(6), and one Se(7) atom. The Se(8)-Se(10) bond length is 1.79 Å. The Se(8)-Se(11) bond length is 2.61 Å. The Se(8)-Se(13) bond length is 2.76 Å. In the ninth Se site, Se(9) is bonded in a distorted single-bond geometry to one Er(3), one Er(5), one Se(14), and one Se(20) atom. The Se(9)-Se(14) bond length is 2.64 Å. The Se(9)-Se(20) bond length is 2.64 Å. In the tenth Se site, Se(10) is bonded in a 1-coordinate geometry to one Se(23), one Se(3), one Se(6), and one Se(8) atom. The Se(10)-Se(23) bond length is 2.23 Å. In the eleventh Se site, Se(11) is bonded in a 6-coordinate geometry to one Er(12), one Er(2), one Se(13), one Se(18), one Se(2), and one Se(8) atom. The Se(11)-Se(13) bond length is 2.21 Å. The Se(11)-Se(18) bond length is 2.50 Å. In the twelfth Se site, Se(12) is bonded in a 1-coordinate geometry to one Er(13), one Se(15), one Se(17), and one Se(23) atom. The Se(12)-Se(15) bond length is 1.83 Å. The Se(12)-Se(17) bond length is 1.46 Å. The Se(12)-Se(23) bond length is 1.99 Å. In the thirteenth Se site, Se(13) is bonded in a 4-coordinate geometry to one Er(11), one Er(12), one Se(11), one Se(21), and one Se(8) atom. The Se(13)-Se(21) bond length is 2.14 Å. In the fourteenth Se site, Se(14) is bonded in a 3-coordinate geometry to one Er(8), one Se(20), and one Se(9) atom. The Se(14)-Se(20) bond length is 2.22 Å. In the fifteenth Se site, Se(15) is bonded in a 6-coordinate geometry to one Er(13), one Er(14), one Se(12), one Se(16), one Se(17), and one Se(24) atom. The Se(15)-Se(16) bond length is 2.12 Å. The Se(15)-Se(17) bond length is 2.06 Å. The Se(15)-Se(24) bond length is 2.23 Å. In the sixteenth Se site, Se(16) is bonded in a 3-coordinate geometry to one Se(15), one Se(22), and one Se(24) atom. The Se(16)-Se(22) bond length is 1.44 Å. The Se(16)-Se(24) bond length is 2.42 Å. In the seventeenth Se site, Se(17) is bonded in a 2-coordinate geometry to one Er(5), one Se(12), one Se(15), and one Se(23) atom. The Se(17)-Se(23) bond length is 2.61 Å. In the eighteenth Se site, Se(18) is bonded in a distorted single-bond geometry to one Er(1), one Er(15), and one Se(11) atom. In the nineteenth Se site, Se(19) is bonded in a distorted single-bond geometry to one Er(15), one Er(2), one Er(3), and one Se(7) atom. In the twentieth Se site, Se(20) is bonded in a 3-coordinate geometry to one Er(3), one Se(14), and one Se(9) atom. In the twenty-first Se site, Se(21) is bonded in a 2-coordinate geometry to one Er(11), one Er(15), and one Se(13) atom. In the twenty-second Se site, Se(22) is bonded in a 4-coordinate geometry to one Er(16), one Er(7), one Er(8), and one Se(16) atom. In the twenty-third Se site, Se(23) is bonded in a 7-coordinate geometry to one Er(2), one Se(1), one Se(10), one Se(12), one Se(17), one Se(24), and one Se(6) atom. The Se(23)-Se(24) bond length is 2.77 Å. In the twenty-fourth Se site, Se(24) is bonded in a 1-coordinate geometry to one Se(15), one Se(16), one Se(23), one Se(3), and one Se(5) atom.