data_Al2TcSe
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.28
_cell_length_b   3.28
_cell_length_c   5.82
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Al2TcSe
_chemical_formula_sum   'Al2 Tc1 Se1'
_cell_volume   62.51
_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
  Al  Al0  1  0.64  0.64  0.22  1.0
  Al  Al1  1  0.64  0.64  0.6  1.0
  Tc  Tc3  1  0.0  0.0  0.91  1.0
  Se  Se2  1  0.0  0.0  0.0  1.0

data_Al2TcSe
_symmetry_space_group_name_H-M   Cm
_cell_length_a   4.64
_cell_length_b   4.64
_cell_length_c   5.82
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Al2TcSe
_chemical_formula_sum   'Al4 Tc2 Se2'
_cell_volume   125.02
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  'x, -y, z'
  3  'x+1/2, y+1/2, z'
  4  'x+1/2, -y+1/2, 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
  Al  Al0  2  0.14  0.5  0.22  1.0
  Al  Al1  2  0.14  0.5  0.6  1.0
  Tc  Tc2  2  0.0  0.0  0.91  1.0
  Se  Se3  2  0.0  0.0  0.0  1.0

Al Al Tc Se
Al Al Tc Se 0 3 + + o 0 2 + + - 0 1 o o o 1 2 + + o 2 3 o o + 
TcAl2Se crystallizes in the monoclinic Cm space group. Tc(1) is bonded in a single-bond geometry to three equivalent Al(2) and one Se(1) atom. There is one shorter (2.46 Å) and two longer (3.00 Å) Tc(1)-Al(2) bond lengths. The Tc(1)-Se(1) bond length is 0.53 Å. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a 1-coordinate geometry to one Al(2) and one Se(1) atom. The Al(1)-Al(2) bond length is 2.22 Å. The Al(1)-Se(1) bond length is 2.10 Å. In the second Al site, Al(2) is bonded in a 4-coordinate geometry to three equivalent Tc(1) and one Al(1) atom. Se(1) is bonded in a distorted single-bond geometry to one Tc(1) and one Al(1) atom.