The structure described by Ta11Al4 is Frank-Kasper $\mu$ Phase-like structured and crystallizes in the monoclinic P2/m space group. There are nine inequivalent Ta sites. In the first Ta site, Ta(1) is bonded in a 14-coordinate geometry to one Ta(3), one Ta(5), one Ta(6), one Ta(7), one Ta(8), one Ta(9), two equivalent Ta(1), two equivalent Ta(4), one Al(1), one Al(2), one Al(3), and one Al(4) atom. In the second Ta site, Ta(2) is bonded in a 14-coordinate geometry to one Ta(4), one Ta(5), one Ta(6), one Ta(7), one Ta(8), one Ta(9), two equivalent Ta(2), two equivalent Ta(3), one Al(1), one Al(2), one Al(3), and one Al(5) atom. In the third Ta site, Ta(3) is bonded in a 15-coordinate geometry to one Ta(3), one Ta(5), one Ta(7), two equivalent Ta(1), four equivalent Ta(2), two equivalent Al(1), two equivalent Al(3), and two equivalent Al(5) atoms. In the fourth Ta site, Ta(4) is bonded in a 15-coordinate geometry to one Ta(4), one Ta(6), one Ta(8), two equivalent Ta(2), two equivalent Ta(9), four equivalent Ta(1), two equivalent Al(2), and two equivalent Al(4) atoms. In the fifth Ta site, Ta(5) is bonded in a 14-coordinate geometry to one Ta(3), one Ta(5), two equivalent Ta(1), two equivalent Ta(2), two equivalent Ta(9), four equivalent Ta(8), and two equivalent Al(3) atoms. In the sixth Ta site, Ta(6) is bonded in a 6-coordinate geometry to one Ta(4), one Ta(6), two equivalent Ta(1), two equivalent Ta(2), two equivalent Al(1), and two equivalent Al(2) atoms. In the seventh Ta site, Ta(7) is bonded in a 6-coordinate geometry to one Ta(3), one Ta(7), two equivalent Ta(1), two equivalent Ta(2), two equivalent Al(1), and two equivalent Al(2) atoms. In the eighth Ta site, Ta(8) is bonded in a 14-coordinate geometry to one Ta(4), one Ta(8), two equivalent Ta(1), two equivalent Ta(2), two equivalent Ta(9), four equivalent Ta(5), and two equivalent Al(3) atoms. In the ninth Ta site, Ta(9) is bonded to two equivalent Ta(1), two equivalent Ta(2), two equivalent Ta(4), two equivalent Ta(5), two equivalent Ta(8), one Al(2), and one Al(4) atom to form distorted TaTa10Al2 cuboctahedra that share  a cornercorner with one Ta(9)Ta10Al2 cuboctahedra, corners with two equivalent Al(4)Ta10Al2 cuboctahedra, corners with two equivalent Al(2)Ta11Al cuboctahedra, corners with two equivalent Al(5)Ta8Al4 cuboctahedra, corners with four equivalent Al(1)Ta10Al2 cuboctahedra, edges with three equivalent Ta(9)Ta10Al2 cuboctahedra,  a faceface with one Al(4)Ta10Al2 cuboctahedra, faces with two equivalent Al(2)Ta11Al cuboctahedra, and faces with four equivalent Al(3)Ta10Al2 cuboctahedra. There are five inequivalent Al sites. In the first Al site, Al(1) is bonded to two equivalent Ta(1), two equivalent Ta(2), two equivalent Ta(3), two equivalent Ta(6), two equivalent Ta(7), one Al(3), and one Al(5) atom to form AlTa10Al2 cuboctahedra that share  a cornercorner with one Al(1)Ta10Al2 cuboctahedra, corners with two equivalent Al(3)Ta10Al2 cuboctahedra, corners with two equivalent Al(4)Ta10Al2 cuboctahedra, corners with two equivalent Al(5)Ta8Al4 cuboctahedra, corners with four equivalent Ta(9)Ta10Al2 cuboctahedra, edges with three equivalent Al(1)Ta10Al2 cuboctahedra,  a faceface with one Al(5)Ta8Al4 cuboctahedra, faces with two equivalent Al(3)Ta10Al2 cuboctahedra, and faces with four equivalent Al(2)Ta11Al cuboctahedra. In the second Al site, Al(2) is bonded to one Ta(9), two equivalent Ta(1), two equivalent Ta(2), two equivalent Ta(4), two equivalent Ta(6), two equivalent Ta(7), and one Al(4) atom to form AlTa11Al cuboctahedra that share  a cornercorner with one Al(2)Ta11Al cuboctahedra, corners with two equivalent Ta(9)Ta10Al2 cuboctahedra, corners with two equivalent Al(4)Ta10Al2 cuboctahedra, corners with two equivalent Al(5)Ta8Al4 cuboctahedra, corners with four equivalent Al(3)Ta10Al2 cuboctahedra, edges with three equivalent Al(2)Ta11Al cuboctahedra,  a faceface with one Al(4)Ta10Al2 cuboctahedra, faces with two equivalent Ta(9)Ta10Al2 cuboctahedra, and faces with four equivalent Al(1)Ta10Al2 cuboctahedra. In the third Al site, Al(3) is bonded to two equivalent Ta(1), two equivalent Ta(2), two equivalent Ta(3), two equivalent Ta(5), two equivalent Ta(8), one Al(1), and one Al(5) atom to form AlTa10Al2 cuboctahedra that share  a cornercorner with one Al(3)Ta10Al2 cuboctahedra, corners with two equivalent Al(1)Ta10Al2 cuboctahedra, corners with two equivalent Al(4)Ta10Al2 cuboctahedra, corners with two equivalent Al(5)Ta8Al4 cuboctahedra, corners with four equivalent Al(2)Ta11Al cuboctahedra, edges with three equivalent Al(3)Ta10Al2 cuboctahedra,  a faceface with one Al(5)Ta8Al4 cuboctahedra, faces with two equivalent Al(1)Ta10Al2 cuboctahedra, and faces with four equivalent Ta(9)Ta10Al2 cuboctahedra. In the fourth Al site, Al(4) is bonded to two equivalent Ta(9), four equivalent Ta(1), four equivalent Ta(4), and two equivalent Al(2) atoms to form AlTa10Al2 cuboctahedra that share corners with four equivalent Ta(9)Ta10Al2 cuboctahedra, corners with four equivalent Al(1)Ta10Al2 cuboctahedra, corners with four equivalent Al(3)Ta10Al2 cuboctahedra, corners with four equivalent Al(2)Ta11Al cuboctahedra, edges with two equivalent Al(4)Ta10Al2 cuboctahedra, faces with two equivalent Ta(9)Ta10Al2 cuboctahedra, and faces with two equivalent Al(2)Ta11Al cuboctahedra. In the fifth Al site, Al(5) is bonded to four equivalent Ta(2), four equivalent Ta(3), two equivalent Al(1), and two equivalent Al(3) atoms to form AlTa8Al4 cuboctahedra that share corners with four equivalent Ta(9)Ta10Al2 cuboctahedra, corners with four equivalent Al(1)Ta10Al2 cuboctahedra, corners with four equivalent Al(3)Ta10Al2 cuboctahedra, corners with four equivalent Al(2)Ta11Al cuboctahedra, edges with two equivalent Al(5)Ta8Al4 cuboctahedra, faces with two equivalent Al(1)Ta10Al2 cuboctahedra, and faces with two equivalent Al(3)Ta10Al2 cuboctahedra. is represented by the CIF file [CIF]
data_Ta11Al4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.184
_cell_length_b   9.978
_cell_length_c   10.059
_cell_angle_alpha   89.478
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   520.344
_cell_formula_units_Z   2
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
  Ta  Ta0  1  0.250  0.319  0.684  1.0
  Ta  Ta1  1  0.250  0.681  0.316  1.0
  Ta  Ta2  1  0.746  0.818  0.821  1.0
  Ta  Ta3  1  0.746  0.182  0.179  1.0
  Ta  Ta4  1  0.750  0.681  0.316  1.0
  Ta  Ta5  1  0.750  0.319  0.684  1.0
  Ta  Ta6  1  0.254  0.182  0.179  1.0
  Ta  Ta7  1  0.254  0.818  0.821  1.0
  Ta  Ta8  1  0.500  0.103  0.897  1.0
  Ta  Ta9  1  0.500  0.897  0.103  1.0
  Ta  Ta10  1  0.000  0.603  0.602  1.0
  Ta  Ta11  1  0.000  0.397  0.398  1.0
  Ta  Ta12  1  0.500  0.036  0.630  1.0
  Ta  Ta13  1  0.500  0.964  0.370  1.0
  Ta  Ta14  1  0.000  0.536  0.874  1.0
  Ta  Ta15  1  0.000  0.464  0.126  1.0
  Ta  Ta16  1  0.500  0.628  0.036  1.0
  Ta  Ta17  1  0.500  0.372  0.964  1.0
  Ta  Ta18  1  0.000  0.871  0.537  1.0
  Ta  Ta19  1  0.000  0.129  0.463  1.0
  Ta  Ta20  1  0.500  0.758  0.566  1.0
  Ta  Ta21  1  0.500  0.242  0.434  1.0
  Al  Al22  1  0.000  0.263  0.935  1.0
  Al  Al23  1  0.000  0.737  0.065  1.0
  Al  Al24  1  0.500  0.566  0.764  1.0
  Al  Al25  1  0.500  0.434  0.236  1.0
  Al  Al26  1  0.000  0.933  0.260  1.0
  Al  Al27  1  0.000  0.067  0.740  1.0
  Al  Al28  1  0.500  0.500  0.500  1.0
  Al  Al29  1  0.000  0.000  0.000  1.0
[/CIF]
.
The structure described by Ta11Al4 is Frank-Kasper $\mu$ Phase-like structured and crystallizes in the monoclinic P2/m space group. There are nine inequivalent Ta sites. In the first Ta site, Ta(1) is bonded in a 14-coordinate geometry to one Ta(3), one Ta(5), one Ta(6), one Ta(7), one Ta(8), one Ta(9), two equivalent Ta(1), two equivalent Ta(4), one Al(1), one Al(2), one Al(3), and one Al(4) atom. In the second Ta site, Ta(2) is bonded in a 14-coordinate geometry to one Ta(4), one Ta(5), one Ta(6), one Ta(7), one Ta(8), one Ta(9), two equivalent Ta(2), two equivalent Ta(3), one Al(1), one Al(2), one Al(3), and one Al(5) atom. In the third Ta site, Ta(3) is bonded in a 15-coordinate geometry to one Ta(3), one Ta(5), one Ta(7), two equivalent Ta(1), four equivalent Ta(2), two equivalent Al(1), two equivalent Al(3), and two equivalent Al(5) atoms. In the fourth Ta site, Ta(4) is bonded in a 15-coordinate geometry to one Ta(4), one Ta(6), one Ta(8), two equivalent Ta(2), two equivalent Ta(9), four equivalent Ta(1), two equivalent Al(2), and two equivalent Al(4) atoms. In the fifth Ta site, Ta(5) is bonded in a 14-coordinate geometry to one Ta(3), one Ta(5), two equivalent Ta(1), two equivalent Ta(2), two equivalent Ta(9), four equivalent Ta(8), and two equivalent Al(3) atoms. In the sixth Ta site, Ta(6) is bonded in a 6-coordinate geometry to one Ta(4), one Ta(6), two equivalent Ta(1), two equivalent Ta(2), two equivalent Al(1), and two equivalent Al(2) atoms. In the seventh Ta site, Ta(7) is bonded in a 6-coordinate geometry to one Ta(3), one Ta(7), two equivalent Ta(1), two equivalent Ta(2), two equivalent Al(1), and two equivalent Al(2) atoms. In the eighth Ta site, Ta(8) is bonded in a 14-coordinate geometry to one Ta(4), one Ta(8), two equivalent Ta(1), two equivalent Ta(2), two equivalent Ta(9), four equivalent Ta(5), and two equivalent Al(3) atoms. In the ninth Ta site, Ta(9) is bonded to two equivalent Ta(1), two equivalent Ta(2), two equivalent Ta(4), two equivalent Ta(5), two equivalent Ta(8), one Al(2), and one Al(4) atom to form distorted TaTa10Al2 cuboctahedra that share  a cornercorner with one Ta(9)Ta10Al2 cuboctahedra, corners with two equivalent Al(4)Ta10Al2 cuboctahedra, corners with two equivalent Al(2)Ta11Al cuboctahedra, corners with two equivalent Al(5)Ta8Al4 cuboctahedra, corners with four equivalent Al(1)Ta10Al2 cuboctahedra, edges with three equivalent Ta(9)Ta10Al2 cuboctahedra,  a faceface with one Al(4)Ta10Al2 cuboctahedra, faces with two equivalent Al(2)Ta11Al cuboctahedra, and faces with four equivalent Al(3)Ta10Al2 cuboctahedra. There are five inequivalent Al sites. In the first Al site, Al(1) is bonded to two equivalent Ta(1), two equivalent Ta(2), two equivalent Ta(3), two equivalent Ta(6), two equivalent Ta(7), one Al(3), and one Al(5) atom to form AlTa10Al2 cuboctahedra that share  a cornercorner with one Al(1)Ta10Al2 cuboctahedra, corners with two equivalent Al(3)Ta10Al2 cuboctahedra, corners with two equivalent Al(4)Ta10Al2 cuboctahedra, corners with two equivalent Al(5)Ta8Al4 cuboctahedra, corners with four equivalent Ta(9)Ta10Al2 cuboctahedra, edges with three equivalent Al(1)Ta10Al2 cuboctahedra,  a faceface with one Al(5)Ta8Al4 cuboctahedra, faces with two equivalent Al(3)Ta10Al2 cuboctahedra, and faces with four equivalent Al(2)Ta11Al cuboctahedra. In the second Al site, Al(2) is bonded to one Ta(9), two equivalent Ta(1), two equivalent Ta(2), two equivalent Ta(4), two equivalent Ta(6), two equivalent Ta(7), and one Al(4) atom to form AlTa11Al cuboctahedra that share  a cornercorner with one Al(2)Ta11Al cuboctahedra, corners with two equivalent Ta(9)Ta10Al2 cuboctahedra, corners with two equivalent Al(4)Ta10Al2 cuboctahedra, corners with two equivalent Al(5)Ta8Al4 cuboctahedra, corners with four equivalent Al(3)Ta10Al2 cuboctahedra, edges with three equivalent Al(2)Ta11Al cuboctahedra,  a faceface with one Al(4)Ta10Al2 cuboctahedra, faces with two equivalent Ta(9)Ta10Al2 cuboctahedra, and faces with four equivalent Al(1)Ta10Al2 cuboctahedra. In the third Al site, Al(3) is bonded to two equivalent Ta(1), two equivalent Ta(2), two equivalent Ta(3), two equivalent Ta(5), two equivalent Ta(8), one Al(1), and one Al(5) atom to form AlTa10Al2 cuboctahedra that share  a cornercorner with one Al(3)Ta10Al2 cuboctahedra, corners with two equivalent Al(1)Ta10Al2 cuboctahedra, corners with two equivalent Al(4)Ta10Al2 cuboctahedra, corners with two equivalent Al(5)Ta8Al4 cuboctahedra, corners with four equivalent Al(2)Ta11Al cuboctahedra, edges with three equivalent Al(3)Ta10Al2 cuboctahedra,  a faceface with one Al(5)Ta8Al4 cuboctahedra, faces with two equivalent Al(1)Ta10Al2 cuboctahedra, and faces with four equivalent Ta(9)Ta10Al2 cuboctahedra. In the fourth Al site, Al(4) is bonded to two equivalent Ta(9), four equivalent Ta(1), four equivalent Ta(4), and two equivalent Al(2) atoms to form AlTa10Al2 cuboctahedra that share corners with four equivalent Ta(9)Ta10Al2 cuboctahedra, corners with four equivalent Al(1)Ta10Al2 cuboctahedra, corners with four equivalent Al(3)Ta10Al2 cuboctahedra, corners with four equivalent Al(2)Ta11Al cuboctahedra, edges with two equivalent Al(4)Ta10Al2 cuboctahedra, faces with two equivalent Ta(9)Ta10Al2 cuboctahedra, and faces with two equivalent Al(2)Ta11Al cuboctahedra. In the fifth Al site, Al(5) is bonded to four equivalent Ta(2), four equivalent Ta(3), two equivalent Al(1), and two equivalent Al(3) atoms to form AlTa8Al4 cuboctahedra that share corners with four equivalent Ta(9)Ta10Al2 cuboctahedra, corners with four equivalent Al(1)Ta10Al2 cuboctahedra, corners with four equivalent Al(3)Ta10Al2 cuboctahedra, corners with four equivalent Al(2)Ta11Al cuboctahedra, edges with two equivalent Al(5)Ta8Al4 cuboctahedra, faces with two equivalent Al(1)Ta10Al2 cuboctahedra, and faces with two equivalent Al(3)Ta10Al2 cuboctahedra. is represented by the CIF file [CIF]
data_Ta11Al4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.184
_cell_length_b   9.978
_cell_length_c   10.059
_cell_angle_alpha   89.478
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   520.344
_cell_formula_units_Z   2
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
  Ta  Ta0  1  0.250  0.319  0.684  1.0
  Ta  Ta1  1  0.250  0.681  0.316  1.0
  Ta  Ta2  1  0.746  0.818  0.821  1.0
  Ta  Ta3  1  0.746  0.182  0.179  1.0
  Ta  Ta4  1  0.750  0.681  0.316  1.0
  Ta  Ta5  1  0.750  0.319  0.684  1.0
  Ta  Ta6  1  0.254  0.182  0.179  1.0
  Ta  Ta7  1  0.254  0.818  0.821  1.0
  Ta  Ta8  1  0.500  0.103  0.897  1.0
  Ta  Ta9  1  0.500  0.897  0.103  1.0
  Ta  Ta10  1  0.000  0.603  0.602  1.0
  Ta  Ta11  1  0.000  0.397  0.398  1.0
  Ta  Ta12  1  0.500  0.036  0.630  1.0
  Ta  Ta13  1  0.500  0.964  0.370  1.0
  Ta  Ta14  1  0.000  0.536  0.874  1.0
  Ta  Ta15  1  0.000  0.464  0.126  1.0
  Ta  Ta16  1  0.500  0.628  0.036  1.0
  Ta  Ta17  1  0.500  0.372  0.964  1.0
  Ta  Ta18  1  0.000  0.871  0.537  1.0
  Ta  Ta19  1  0.000  0.129  0.463  1.0
  Ta  Ta20  1  0.500  0.758  0.566  1.0
  Ta  Ta21  1  0.500  0.242  0.434  1.0
  Al  Al22  1  0.000  0.263  0.935  1.0
  Al  Al23  1  0.000  0.737  0.065  1.0
  Al  Al24  1  0.500  0.566  0.764  1.0
  Al  Al25  1  0.500  0.434  0.236  1.0
  Al  Al26  1  0.000  0.933  0.260  1.0
  Al  Al27  1  0.000  0.067  0.740  1.0
  Al  Al28  1  0.500  0.500  0.500  1.0
  Al  Al29  1  0.000  0.000  0.000  1.0
[/CIF]
.