The structure described by Cu19Sn16 crystallizes in the triclinic P1 space group. There are nineteen inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 9-coordinate geometry to one Cu(16), one Cu(19), one Cu(6), one Sn(1), one Sn(12), one Sn(16), one Sn(2), one Sn(5), and one Sn(8) atom. In the second Cu site, Cu(2) is bonded in a distorted q6 geometry to one Cu(15), one Cu(17), one Cu(18), one Cu(5), one Sn(1), one Sn(11), one Sn(15), one Sn(2), one Sn(6), and one Sn(7) atom. In the third Cu site, Cu(3) is bonded in a distorted q6 geometry to one Cu(14), one Cu(17), one Cu(18), one Cu(8), one Sn(10), one Sn(14), one Sn(3), one Sn(4), one Sn(6), and one Sn(7) atom. In the fourth Cu site, Cu(4) is bonded in a 9-coordinate geometry to one Cu(13), one Cu(19), one Cu(7), one Sn(13), one Sn(3), one Sn(4), one Sn(5), one Sn(8), and one Sn(9) atom. In the fifth Cu site, Cu(5) is bonded in a distorted q6 geometry to one Cu(12), one Cu(18), one Cu(2), one Sn(1), one Sn(16), one Sn(2), one Sn(4), one Sn(6), and one Sn(8) atom. In the sixth Cu site, Cu(6) is bonded in a 10-coordinate geometry to one Cu(1), one Cu(11), one Cu(17), one Cu(19), one Sn(1), one Sn(15), one Sn(2), one Sn(3), one Sn(5), and one Sn(7) atom. In the seventh Cu site, Cu(7) is bonded in a 9-coordinate geometry to one Cu(10), one Cu(18), one Cu(4), one Sn(14), one Sn(2), one Sn(3), one Sn(4), one Sn(6), and one Sn(8) atom. In the eighth Cu site, Cu(8) is bonded in a 10-coordinate geometry to one Cu(17), one Cu(19), one Cu(3), one Cu(9), one Sn(1), one Sn(13), one Sn(3), one Sn(4), one Sn(5), and one Sn(7) atom. In the ninth Cu site, Cu(9) is bonded in a 9-coordinate geometry to one Cu(14), one Cu(19), one Cu(8), one Sn(1), one Sn(11), one Sn(12), one Sn(13), one Sn(16), and one Sn(5) atom. In the tenth Cu site, Cu(10) is bonded in a 9-coordinate geometry to one Cu(13), one Cu(18), one Cu(7), one Sn(11), one Sn(12), one Sn(14), one Sn(15), one Sn(2), and one Sn(6) atom. In the eleventh Cu site, Cu(11) is bonded in a 9-coordinate geometry to one Cu(16), one Cu(17), one Cu(6), one Sn(10), one Sn(14), one Sn(15), one Sn(3), one Sn(7), and one Sn(9) atom. In the twelfth Cu site, Cu(12) is bonded in a body-centered cubic geometry to one Cu(15), one Cu(5), one Sn(10), one Sn(13), one Sn(16), one Sn(4), one Sn(8), and one Sn(9) atom. In the thirteenth Cu site, Cu(13) is bonded in a distorted q6 geometry to one Cu(10), one Cu(19), one Cu(4), one Sn(11), one Sn(12), one Sn(13), one Sn(15), one Sn(5), and one Sn(9) atom. In the fourteenth Cu site, Cu(14) is bonded in a distorted q6 geometry to one Cu(18), one Cu(3), one Cu(9), one Sn(10), one Sn(11), one Sn(12), one Sn(14), one Sn(16), and one Sn(6) atom. In the fifteenth Cu site, Cu(15) is bonded in a distorted q6 geometry to one Cu(12), one Cu(17), one Cu(2), one Sn(10), one Sn(11), one Sn(13), one Sn(15), one Sn(7), and one Sn(9) atom. In the sixteenth Cu site, Cu(16) is bonded in a body-centered cubic geometry to one Cu(1), one Cu(11), one Sn(10), one Sn(12), one Sn(14), one Sn(16), one Sn(8), and one Sn(9) atom. In the seventeenth Cu site, Cu(17) is bonded in a 11-coordinate geometry to one Cu(11), one Cu(15), one Cu(2), one Cu(3), one Cu(6), one Cu(8), one Sn(1), one Sn(10), one Sn(15), one Sn(3), and one Sn(7) atom. In the eighteenth Cu site, Cu(18) is bonded in a 11-coordinate geometry to one Cu(10), one Cu(14), one Cu(2), one Cu(3), one Cu(5), one Cu(7), one Sn(11), one Sn(14), one Sn(2), one Sn(4), and one Sn(6) atom. In the nineteenth Cu site, Cu(19) is bonded in a 11-coordinate geometry to one Cu(1), one Cu(13), one Cu(4), one Cu(6), one Cu(8), one Cu(9), one Sn(1), one Sn(12), one Sn(13), one Sn(3), and one Sn(5) atom. There are sixteen inequivalent Sn sites. In the first Sn site, Sn(1) is bonded in a 8-coordinate geometry to one Cu(1), one Cu(17), one Cu(19), one Cu(2), one Cu(5), one Cu(6), one Cu(8), and one Cu(9) atom. In the second Sn site, Sn(2) is bonded in a 7-coordinate geometry to one Cu(1), one Cu(10), one Cu(18), one Cu(2), one Cu(5), one Cu(6), and one Cu(7) atom. In the third Sn site, Sn(3) is bonded in a 8-coordinate geometry to one Cu(11), one Cu(17), one Cu(19), one Cu(3), one Cu(4), one Cu(6), one Cu(7), and one Cu(8) atom. In the fourth Sn site, Sn(4) is bonded in a 7-coordinate geometry to one Cu(12), one Cu(18), one Cu(3), one Cu(4), one Cu(5), one Cu(7), and one Cu(8) atom. In the fifth Sn site, Sn(5) is bonded in a 7-coordinate geometry to one Cu(1), one Cu(13), one Cu(19), one Cu(4), one Cu(6), one Cu(8), and one Cu(9) atom. In the sixth Sn site, Sn(6) is bonded in a 7-coordinate geometry to one Cu(10), one Cu(14), one Cu(18), one Cu(2), one Cu(3), one Cu(5), and one Cu(7) atom. In the seventh Sn site, Sn(7) is bonded in a 7-coordinate geometry to one Cu(11), one Cu(15), one Cu(17), one Cu(2), one Cu(3), one Cu(6), and one Cu(8) atom. In the eighth Sn site, Sn(8) is bonded in a 6-coordinate geometry to one Cu(1), one Cu(12), one Cu(16), one Cu(4), one Cu(5), and one Cu(7) atom. In the ninth Sn site, Sn(9) is bonded in a 6-coordinate geometry to one Cu(11), one Cu(12), one Cu(13), one Cu(15), one Cu(16), and one Cu(4) atom. In the tenth Sn site, Sn(10) is bonded in a 7-coordinate geometry to one Cu(11), one Cu(12), one Cu(14), one Cu(15), one Cu(16), one Cu(17), and one Cu(3) atom. In the eleventh Sn site, Sn(11) is bonded in a 7-coordinate geometry to one Cu(10), one Cu(13), one Cu(14), one Cu(15), one Cu(18), one Cu(2), and one Cu(9) atom. In the twelfth Sn site, Sn(12) is bonded in a 7-coordinate geometry to one Cu(1), one Cu(10), one Cu(13), one Cu(14), one Cu(16), one Cu(19), and one Cu(9) atom. In the thirteenth Sn site, Sn(13) is bonded in a 7-coordinate geometry to one Cu(12), one Cu(13), one Cu(15), one Cu(19), one Cu(4), one Cu(8), and one Cu(9) atom. In the fourteenth Sn site, Sn(14) is bonded in a 7-coordinate geometry to one Cu(10), one Cu(11), one Cu(14), one Cu(16), one Cu(18), one Cu(3), and one Cu(7) atom. In the fifteenth Sn site, Sn(15) is bonded in a 7-coordinate geometry to one Cu(10), one Cu(11), one Cu(13), one Cu(15), one Cu(17), one Cu(2), and one Cu(6) atom. In the sixteenth Sn site, Sn(16) is bonded in a 6-coordinate geometry to one Cu(1), one Cu(12), one Cu(14), one Cu(16), one Cu(5), and one Cu(9) atom. is represented by the CIF file [CIF]
data_Cu19Sn16
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.549
_cell_length_b   9.777
_cell_length_c   9.793
_cell_angle_alpha   116.550
_cell_angle_beta   90.175
_cell_angle_gamma   90.326
_symmetry_Int_Tables_number   1
_cell_volume   646.477
_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
  Cu  Cu0  1  0.758  0.312  0.192  1.0
  Cu  Cu1  1  0.256  0.188  0.810  1.0
  Cu  Cu2  1  0.247  0.687  0.812  1.0
  Cu  Cu3  1  0.746  0.814  0.190  1.0
  Cu  Cu4  1  0.270  0.445  0.060  1.0
  Cu  Cu5  1  0.777  0.058  0.942  1.0
  Cu  Cu6  1  0.723  0.557  0.944  1.0
  Cu  Cu7  1  0.227  0.941  0.059  1.0
  Cu  Cu8  1  0.228  0.187  0.316  1.0
  Cu  Cu9  1  0.724  0.318  0.687  1.0
  Cu  Cu10  1  0.775  0.815  0.682  1.0
  Cu  Cu11  1  0.269  0.682  0.314  1.0
  Cu  Cu12  1  0.744  0.067  0.430  1.0
  Cu  Cu13  1  0.248  0.431  0.566  1.0
  Cu  Cu14  1  0.256  0.931  0.569  1.0
  Cu  Cu15  1  0.755  0.568  0.431  1.0
  Cu  Cu16  1  0.092  0.938  0.809  1.0
  Cu  Cu17  1  0.409  0.438  0.812  1.0
  Cu  Cu18  1  0.908  0.063  0.191  1.0
  Sn  Sn19  1  0.096  0.215  0.069  1.0
  Sn  Sn20  1  0.593  0.293  0.942  1.0
  Sn  Sn21  1  0.906  0.785  0.930  1.0
  Sn  Sn22  1  0.413  0.710  0.077  1.0
  Sn  Sn23  1  0.552  0.063  0.182  1.0
  Sn  Sn24  1  0.053  0.437  0.817  1.0
  Sn  Sn25  1  0.449  0.939  0.816  1.0
  Sn  Sn26  1  0.928  0.562  0.183  1.0
  Sn  Sn27  1  0.588  0.819  0.443  1.0
  Sn  Sn28  1  0.092  0.668  0.544  1.0
  Sn  Sn29  1  0.412  0.169  0.545  1.0
  Sn  Sn30  1  0.910  0.332  0.457  1.0
  Sn  Sn31  1  0.085  0.922  0.322  1.0
  Sn  Sn32  1  0.584  0.577  0.677  1.0
  Sn  Sn33  1  0.912  0.078  0.678  1.0
  Sn  Sn34  1  0.425  0.431  0.314  1.0
[/CIF]
.
The structure described by Cu19Sn16 crystallizes in the triclinic P1 space group. There are nineteen inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 9-coordinate geometry to one Cu(16), one Cu(19), one Cu(6), one Sn(1), one Sn(12), one Sn(16), one Sn(2), one Sn(5), and one Sn(8) atom. In the second Cu site, Cu(2) is bonded in a distorted q6 geometry to one Cu(15), one Cu(17), one Cu(18), one Cu(5), one Sn(1), one Sn(11), one Sn(15), one Sn(2), one Sn(6), and one Sn(7) atom. In the third Cu site, Cu(3) is bonded in a distorted q6 geometry to one Cu(14), one Cu(17), one Cu(18), one Cu(8), one Sn(10), one Sn(14), one Sn(3), one Sn(4), one Sn(6), and one Sn(7) atom. In the fourth Cu site, Cu(4) is bonded in a 9-coordinate geometry to one Cu(13), one Cu(19), one Cu(7), one Sn(13), one Sn(3), one Sn(4), one Sn(5), one Sn(8), and one Sn(9) atom. In the fifth Cu site, Cu(5) is bonded in a distorted q6 geometry to one Cu(12), one Cu(18), one Cu(2), one Sn(1), one Sn(16), one Sn(2), one Sn(4), one Sn(6), and one Sn(8) atom. In the sixth Cu site, Cu(6) is bonded in a 10-coordinate geometry to one Cu(1), one Cu(11), one Cu(17), one Cu(19), one Sn(1), one Sn(15), one Sn(2), one Sn(3), one Sn(5), and one Sn(7) atom. In the seventh Cu site, Cu(7) is bonded in a 9-coordinate geometry to one Cu(10), one Cu(18), one Cu(4), one Sn(14), one Sn(2), one Sn(3), one Sn(4), one Sn(6), and one Sn(8) atom. In the eighth Cu site, Cu(8) is bonded in a 10-coordinate geometry to one Cu(17), one Cu(19), one Cu(3), one Cu(9), one Sn(1), one Sn(13), one Sn(3), one Sn(4), one Sn(5), and one Sn(7) atom. In the ninth Cu site, Cu(9) is bonded in a 9-coordinate geometry to one Cu(14), one Cu(19), one Cu(8), one Sn(1), one Sn(11), one Sn(12), one Sn(13), one Sn(16), and one Sn(5) atom. In the tenth Cu site, Cu(10) is bonded in a 9-coordinate geometry to one Cu(13), one Cu(18), one Cu(7), one Sn(11), one Sn(12), one Sn(14), one Sn(15), one Sn(2), and one Sn(6) atom. In the eleventh Cu site, Cu(11) is bonded in a 9-coordinate geometry to one Cu(16), one Cu(17), one Cu(6), one Sn(10), one Sn(14), one Sn(15), one Sn(3), one Sn(7), and one Sn(9) atom. In the twelfth Cu site, Cu(12) is bonded in a body-centered cubic geometry to one Cu(15), one Cu(5), one Sn(10), one Sn(13), one Sn(16), one Sn(4), one Sn(8), and one Sn(9) atom. In the thirteenth Cu site, Cu(13) is bonded in a distorted q6 geometry to one Cu(10), one Cu(19), one Cu(4), one Sn(11), one Sn(12), one Sn(13), one Sn(15), one Sn(5), and one Sn(9) atom. In the fourteenth Cu site, Cu(14) is bonded in a distorted q6 geometry to one Cu(18), one Cu(3), one Cu(9), one Sn(10), one Sn(11), one Sn(12), one Sn(14), one Sn(16), and one Sn(6) atom. In the fifteenth Cu site, Cu(15) is bonded in a distorted q6 geometry to one Cu(12), one Cu(17), one Cu(2), one Sn(10), one Sn(11), one Sn(13), one Sn(15), one Sn(7), and one Sn(9) atom. In the sixteenth Cu site, Cu(16) is bonded in a body-centered cubic geometry to one Cu(1), one Cu(11), one Sn(10), one Sn(12), one Sn(14), one Sn(16), one Sn(8), and one Sn(9) atom. In the seventeenth Cu site, Cu(17) is bonded in a 11-coordinate geometry to one Cu(11), one Cu(15), one Cu(2), one Cu(3), one Cu(6), one Cu(8), one Sn(1), one Sn(10), one Sn(15), one Sn(3), and one Sn(7) atom. In the eighteenth Cu site, Cu(18) is bonded in a 11-coordinate geometry to one Cu(10), one Cu(14), one Cu(2), one Cu(3), one Cu(5), one Cu(7), one Sn(11), one Sn(14), one Sn(2), one Sn(4), and one Sn(6) atom. In the nineteenth Cu site, Cu(19) is bonded in a 11-coordinate geometry to one Cu(1), one Cu(13), one Cu(4), one Cu(6), one Cu(8), one Cu(9), one Sn(1), one Sn(12), one Sn(13), one Sn(3), and one Sn(5) atom. There are sixteen inequivalent Sn sites. In the first Sn site, Sn(1) is bonded in a 8-coordinate geometry to one Cu(1), one Cu(17), one Cu(19), one Cu(2), one Cu(5), one Cu(6), one Cu(8), and one Cu(9) atom. In the second Sn site, Sn(2) is bonded in a 7-coordinate geometry to one Cu(1), one Cu(10), one Cu(18), one Cu(2), one Cu(5), one Cu(6), and one Cu(7) atom. In the third Sn site, Sn(3) is bonded in a 8-coordinate geometry to one Cu(11), one Cu(17), one Cu(19), one Cu(3), one Cu(4), one Cu(6), one Cu(7), and one Cu(8) atom. In the fourth Sn site, Sn(4) is bonded in a 7-coordinate geometry to one Cu(12), one Cu(18), one Cu(3), one Cu(4), one Cu(5), one Cu(7), and one Cu(8) atom. In the fifth Sn site, Sn(5) is bonded in a 7-coordinate geometry to one Cu(1), one Cu(13), one Cu(19), one Cu(4), one Cu(6), one Cu(8), and one Cu(9) atom. In the sixth Sn site, Sn(6) is bonded in a 7-coordinate geometry to one Cu(10), one Cu(14), one Cu(18), one Cu(2), one Cu(3), one Cu(5), and one Cu(7) atom. In the seventh Sn site, Sn(7) is bonded in a 7-coordinate geometry to one Cu(11), one Cu(15), one Cu(17), one Cu(2), one Cu(3), one Cu(6), and one Cu(8) atom. In the eighth Sn site, Sn(8) is bonded in a 6-coordinate geometry to one Cu(1), one Cu(12), one Cu(16), one Cu(4), one Cu(5), and one Cu(7) atom. In the ninth Sn site, Sn(9) is bonded in a 6-coordinate geometry to one Cu(11), one Cu(12), one Cu(13), one Cu(15), one Cu(16), and one Cu(4) atom. In the tenth Sn site, Sn(10) is bonded in a 7-coordinate geometry to one Cu(11), one Cu(12), one Cu(14), one Cu(15), one Cu(16), one Cu(17), and one Cu(3) atom. In the eleventh Sn site, Sn(11) is bonded in a 7-coordinate geometry to one Cu(10), one Cu(13), one Cu(14), one Cu(15), one Cu(18), one Cu(2), and one Cu(9) atom. In the twelfth Sn site, Sn(12) is bonded in a 7-coordinate geometry to one Cu(1), one Cu(10), one Cu(13), one Cu(14), one Cu(16), one Cu(19), and one Cu(9) atom. In the thirteenth Sn site, Sn(13) is bonded in a 7-coordinate geometry to one Cu(12), one Cu(13), one Cu(15), one Cu(19), one Cu(4), one Cu(8), and one Cu(9) atom. In the fourteenth Sn site, Sn(14) is bonded in a 7-coordinate geometry to one Cu(10), one Cu(11), one Cu(14), one Cu(16), one Cu(18), one Cu(3), and one Cu(7) atom. In the fifteenth Sn site, Sn(15) is bonded in a 7-coordinate geometry to one Cu(10), one Cu(11), one Cu(13), one Cu(15), one Cu(17), one Cu(2), and one Cu(6) atom. In the sixteenth Sn site, Sn(16) is bonded in a 6-coordinate geometry to one Cu(1), one Cu(12), one Cu(14), one Cu(16), one Cu(5), and one Cu(9) atom. is represented by the CIF file [CIF]
data_Cu19Sn16
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.549
_cell_length_b   9.777
_cell_length_c   9.793
_cell_angle_alpha   116.550
_cell_angle_beta   90.175
_cell_angle_gamma   90.326
_symmetry_Int_Tables_number   1
_cell_volume   646.477
_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
  Cu  Cu0  1  0.758  0.312  0.192  1.0
  Cu  Cu1  1  0.256  0.188  0.810  1.0
  Cu  Cu2  1  0.247  0.687  0.812  1.0
  Cu  Cu3  1  0.746  0.814  0.190  1.0
  Cu  Cu4  1  0.270  0.445  0.060  1.0
  Cu  Cu5  1  0.777  0.058  0.942  1.0
  Cu  Cu6  1  0.723  0.557  0.944  1.0
  Cu  Cu7  1  0.227  0.941  0.059  1.0
  Cu  Cu8  1  0.228  0.187  0.316  1.0
  Cu  Cu9  1  0.724  0.318  0.687  1.0
  Cu  Cu10  1  0.775  0.815  0.682  1.0
  Cu  Cu11  1  0.269  0.682  0.314  1.0
  Cu  Cu12  1  0.744  0.067  0.430  1.0
  Cu  Cu13  1  0.248  0.431  0.566  1.0
  Cu  Cu14  1  0.256  0.931  0.569  1.0
  Cu  Cu15  1  0.755  0.568  0.431  1.0
  Cu  Cu16  1  0.092  0.938  0.809  1.0
  Cu  Cu17  1  0.409  0.438  0.812  1.0
  Cu  Cu18  1  0.908  0.063  0.191  1.0
  Sn  Sn19  1  0.096  0.215  0.069  1.0
  Sn  Sn20  1  0.593  0.293  0.942  1.0
  Sn  Sn21  1  0.906  0.785  0.930  1.0
  Sn  Sn22  1  0.413  0.710  0.077  1.0
  Sn  Sn23  1  0.552  0.063  0.182  1.0
  Sn  Sn24  1  0.053  0.437  0.817  1.0
  Sn  Sn25  1  0.449  0.939  0.816  1.0
  Sn  Sn26  1  0.928  0.562  0.183  1.0
  Sn  Sn27  1  0.588  0.819  0.443  1.0
  Sn  Sn28  1  0.092  0.668  0.544  1.0
  Sn  Sn29  1  0.412  0.169  0.545  1.0
  Sn  Sn30  1  0.910  0.332  0.457  1.0
  Sn  Sn31  1  0.085  0.922  0.322  1.0
  Sn  Sn32  1  0.584  0.577  0.677  1.0
  Sn  Sn33  1  0.912  0.078  0.678  1.0
  Sn  Sn34  1  0.425  0.431  0.314  1.0
[/CIF]
.