The crystal structure described by Ta19(MoNi9)2 is Frank-Kasper $\mu$ Phase-derived structured and crystallizes in the trigonal P-3m1 space group. There are ten inequivalent Ta sites. In the first Ta site, Ta(1) is bonded in a 16-coordinate geometry to one Ta(4), three equivalent Ta(2), three equivalent Mo(1), three equivalent Ni(2), and six equivalent Ni(3) atoms. In the second Ta site, Ta(2) is bonded in a 16-coordinate geometry to one Ta(5), three equivalent Ta(1), three equivalent Mo(1), three equivalent Ni(3), and six equivalent Ni(2) atoms. In the third Ta site, Ta(3) is bonded in a 16-coordinate geometry to one Ta(6), three equivalent Ta(10), three equivalent Ta(3), and nine equivalent Ni(1) atoms. In the fourth Ta site, Ta(4) is bonded in a 14-coordinate geometry to one Ta(1), one Ta(6), three equivalent Ta(7), three equivalent Ta(9), and six equivalent Ni(3) atoms. In the fifth Ta site, Ta(5) is bonded in a 14-coordinate geometry to one Ta(2), one Ta(5), six equivalent Ta(8), and six equivalent Ni(2) atoms. In the sixth Ta site, Ta(6) is bonded in a 14-coordinate geometry to one Ta(3), one Ta(4), three equivalent Ta(7), three equivalent Ta(9), and six equivalent Ni(1) atoms. In the seventh Ta site, Ta(7) is bonded in a 6-coordinate geometry to three equivalent Ta(4), three equivalent Ta(6), three equivalent Ni(1), and three equivalent Ni(3) atoms. In the eighth Ta site, Ta(8) is bonded in a 6-coordinate geometry to six equivalent Ta(5) and six equivalent Ni(2) atoms. In the ninth Ta site, Ta(9) is bonded in a 6-coordinate geometry to three equivalent Ta(4), three equivalent Ta(6), three equivalent Ni(1), and three equivalent Ni(3) atoms. In the tenth Ta site, Ta(10) is bonded to six equivalent Ta(3) and six equivalent Ni(1) atoms to form distorted TaTa6Ni6 cuboctahedra that share corners with twelve equivalent Ni(1)Ta8Ni4 cuboctahedra, edges with six equivalent Ta(10)Ta6Ni6 cuboctahedra, and faces with eighteen equivalent Ni(1)Ta8Ni4 cuboctahedra. Mo(1) is bonded to three equivalent Ta(1), three equivalent Ta(2), three equivalent Ni(2), and three equivalent Ni(3) atoms to form MoTa6Ni6 cuboctahedra that share corners with six equivalent Ni(2)Ta7Ni4Mo cuboctahedra, corners with six equivalent Ni(3)Ta7Ni4Mo cuboctahedra, edges with six equivalent Mo(1)Ta6Ni6 cuboctahedra, faces with nine equivalent Ni(2)Ta7Ni4Mo cuboctahedra, and faces with nine equivalent Ni(3)Ta7Ni4Mo cuboctahedra. There are three inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one Ta(10), one Ta(7), one Ta(9), two equivalent Ta(6), three equivalent Ta(3), and four equivalent Ni(1) atoms to form distorted NiTa8Ni4 cuboctahedra that share corners with two equivalent Ta(10)Ta6Ni6 cuboctahedra, corners with four equivalent Ni(3)Ta7Ni4Mo cuboctahedra, corners with nine equivalent Ni(1)Ta8Ni4 cuboctahedra,  an edgeedge with one Ni(3)Ta7Ni4Mo cuboctahedra, edges with four equivalent Ni(1)Ta8Ni4 cuboctahedra, faces with three equivalent Ta(10)Ta6Ni6 cuboctahedra, and faces with ten equivalent Ni(1)Ta8Ni4 cuboctahedra. In the second Ni site, Ni(2) is bonded to one Ta(1), two equivalent Ta(2), two equivalent Ta(5), two equivalent Ta(8), one Mo(1), and four equivalent Ni(2) atoms to form distorted NiTa7Ni4Mo cuboctahedra that share corners with two equivalent Mo(1)Ta6Ni6 cuboctahedra, corners with five equivalent Ni(3)Ta7Ni4Mo cuboctahedra, corners with eight equivalent Ni(2)Ta7Ni4Mo cuboctahedra, edges with two equivalent Ni(3)Ta7Ni4Mo cuboctahedra, edges with three equivalent Ni(2)Ta7Ni4Mo cuboctahedra, faces with two equivalent Ni(3)Ta7Ni4Mo cuboctahedra, faces with three equivalent Mo(1)Ta6Ni6 cuboctahedra, and faces with eight equivalent Ni(2)Ta7Ni4Mo cuboctahedra. In the third Ni site, Ni(3) is bonded to one Ta(2), one Ta(7), one Ta(9), two equivalent Ta(1), two equivalent Ta(4), one Mo(1), and four equivalent Ni(3) atoms to form distorted NiTa7Ni4Mo cuboctahedra that share corners with two equivalent Mo(1)Ta6Ni6 cuboctahedra, corners with four equivalent Ni(3)Ta7Ni4Mo cuboctahedra, corners with four equivalent Ni(1)Ta8Ni4 cuboctahedra, corners with five equivalent Ni(2)Ta7Ni4Mo cuboctahedra,  an edgeedge with one Ni(1)Ta8Ni4 cuboctahedra, edges with two equivalent Ni(2)Ta7Ni4Mo cuboctahedra, edges with two equivalent Ni(3)Ta7Ni4Mo cuboctahedra, faces with two equivalent Ni(2)Ta7Ni4Mo cuboctahedra, faces with three equivalent Mo(1)Ta6Ni6 cuboctahedra, and faces with eight equivalent Ni(3)Ta7Ni4Mo cuboctahedra. is represented by the CIF card [CIF]
data_Ta19(Ni9Mo)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.917
_cell_length_b   4.917
_cell_length_c   27.071
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   566.802
_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
  Ta  Ta0  1  0.667  0.333  0.321  1.0
  Ta  Ta1  1  0.000  0.000  0.654  1.0
  Ta  Ta2  1  0.333  0.667  0.988  1.0
  Ta  Ta3  1  0.667  0.333  0.012  1.0
  Ta  Ta4  1  0.000  0.000  0.346  1.0
  Ta  Ta5  1  0.333  0.667  0.679  1.0
  Ta  Ta6  1  0.667  0.333  0.216  1.0
  Ta  Ta7  1  0.000  0.000  0.549  1.0
  Ta  Ta8  1  0.333  0.667  0.882  1.0
  Ta  Ta9  1  0.667  0.333  0.118  1.0
  Ta  Ta10  1  0.000  0.000  0.451  1.0
  Ta  Ta11  1  0.333  0.667  0.784  1.0
  Ta  Ta12  1  0.333  0.667  0.169  1.0
  Ta  Ta13  1  0.667  0.333  0.503  1.0
  Ta  Ta14  1  0.000  0.000  0.836  1.0
  Ta  Ta15  1  0.000  0.000  0.164  1.0
  Ta  Ta16  1  0.333  0.667  0.497  1.0
  Ta  Ta17  1  0.667  0.333  0.831  1.0
  Ta  Ta18  1  0.000  0.000  0.000  1.0
  Ni  Ni19  1  0.169  0.831  0.078  1.0
  Ni  Ni20  1  0.502  0.498  0.411  1.0
  Ni  Ni21  1  0.835  0.165  0.744  1.0
  Ni  Ni22  1  0.661  0.831  0.078  1.0
  Ni  Ni23  1  0.997  0.498  0.411  1.0
  Ni  Ni24  1  0.330  0.165  0.744  1.0
  Ni  Ni25  1  0.169  0.339  0.078  1.0
  Ni  Ni26  1  0.502  0.003  0.411  1.0
  Ni  Ni27  1  0.835  0.670  0.744  1.0
  Ni  Ni28  1  0.165  0.835  0.256  1.0
  Ni  Ni29  1  0.498  0.502  0.589  1.0
  Ni  Ni30  1  0.831  0.169  0.922  1.0
  Ni  Ni31  1  0.670  0.835  0.256  1.0
  Ni  Ni32  1  0.003  0.502  0.589  1.0
  Ni  Ni33  1  0.339  0.169  0.922  1.0
  Ni  Ni34  1  0.165  0.330  0.256  1.0
  Ni  Ni35  1  0.498  0.997  0.589  1.0
  Ni  Ni36  1  0.831  0.661  0.922  1.0
  Mo  Mo37  1  0.333  0.667  0.333  1.0
  Mo  Mo38  1  0.667  0.333  0.667  1.0
[/CIF]
.
The crystal structure described by Ta19(MoNi9)2 is Frank-Kasper $\mu$ Phase-derived structured and crystallizes in the trigonal P-3m1 space group. There are ten inequivalent Ta sites. In the first Ta site, Ta(1) is bonded in a 16-coordinate geometry to one Ta(4), three equivalent Ta(2), three equivalent Mo(1), three equivalent Ni(2), and six equivalent Ni(3) atoms. In the second Ta site, Ta(2) is bonded in a 16-coordinate geometry to one Ta(5), three equivalent Ta(1), three equivalent Mo(1), three equivalent Ni(3), and six equivalent Ni(2) atoms. In the third Ta site, Ta(3) is bonded in a 16-coordinate geometry to one Ta(6), three equivalent Ta(10), three equivalent Ta(3), and nine equivalent Ni(1) atoms. In the fourth Ta site, Ta(4) is bonded in a 14-coordinate geometry to one Ta(1), one Ta(6), three equivalent Ta(7), three equivalent Ta(9), and six equivalent Ni(3) atoms. In the fifth Ta site, Ta(5) is bonded in a 14-coordinate geometry to one Ta(2), one Ta(5), six equivalent Ta(8), and six equivalent Ni(2) atoms. In the sixth Ta site, Ta(6) is bonded in a 14-coordinate geometry to one Ta(3), one Ta(4), three equivalent Ta(7), three equivalent Ta(9), and six equivalent Ni(1) atoms. In the seventh Ta site, Ta(7) is bonded in a 6-coordinate geometry to three equivalent Ta(4), three equivalent Ta(6), three equivalent Ni(1), and three equivalent Ni(3) atoms. In the eighth Ta site, Ta(8) is bonded in a 6-coordinate geometry to six equivalent Ta(5) and six equivalent Ni(2) atoms. In the ninth Ta site, Ta(9) is bonded in a 6-coordinate geometry to three equivalent Ta(4), three equivalent Ta(6), three equivalent Ni(1), and three equivalent Ni(3) atoms. In the tenth Ta site, Ta(10) is bonded to six equivalent Ta(3) and six equivalent Ni(1) atoms to form distorted TaTa6Ni6 cuboctahedra that share corners with twelve equivalent Ni(1)Ta8Ni4 cuboctahedra, edges with six equivalent Ta(10)Ta6Ni6 cuboctahedra, and faces with eighteen equivalent Ni(1)Ta8Ni4 cuboctahedra. Mo(1) is bonded to three equivalent Ta(1), three equivalent Ta(2), three equivalent Ni(2), and three equivalent Ni(3) atoms to form MoTa6Ni6 cuboctahedra that share corners with six equivalent Ni(2)Ta7Ni4Mo cuboctahedra, corners with six equivalent Ni(3)Ta7Ni4Mo cuboctahedra, edges with six equivalent Mo(1)Ta6Ni6 cuboctahedra, faces with nine equivalent Ni(2)Ta7Ni4Mo cuboctahedra, and faces with nine equivalent Ni(3)Ta7Ni4Mo cuboctahedra. There are three inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one Ta(10), one Ta(7), one Ta(9), two equivalent Ta(6), three equivalent Ta(3), and four equivalent Ni(1) atoms to form distorted NiTa8Ni4 cuboctahedra that share corners with two equivalent Ta(10)Ta6Ni6 cuboctahedra, corners with four equivalent Ni(3)Ta7Ni4Mo cuboctahedra, corners with nine equivalent Ni(1)Ta8Ni4 cuboctahedra,  an edgeedge with one Ni(3)Ta7Ni4Mo cuboctahedra, edges with four equivalent Ni(1)Ta8Ni4 cuboctahedra, faces with three equivalent Ta(10)Ta6Ni6 cuboctahedra, and faces with ten equivalent Ni(1)Ta8Ni4 cuboctahedra. In the second Ni site, Ni(2) is bonded to one Ta(1), two equivalent Ta(2), two equivalent Ta(5), two equivalent Ta(8), one Mo(1), and four equivalent Ni(2) atoms to form distorted NiTa7Ni4Mo cuboctahedra that share corners with two equivalent Mo(1)Ta6Ni6 cuboctahedra, corners with five equivalent Ni(3)Ta7Ni4Mo cuboctahedra, corners with eight equivalent Ni(2)Ta7Ni4Mo cuboctahedra, edges with two equivalent Ni(3)Ta7Ni4Mo cuboctahedra, edges with three equivalent Ni(2)Ta7Ni4Mo cuboctahedra, faces with two equivalent Ni(3)Ta7Ni4Mo cuboctahedra, faces with three equivalent Mo(1)Ta6Ni6 cuboctahedra, and faces with eight equivalent Ni(2)Ta7Ni4Mo cuboctahedra. In the third Ni site, Ni(3) is bonded to one Ta(2), one Ta(7), one Ta(9), two equivalent Ta(1), two equivalent Ta(4), one Mo(1), and four equivalent Ni(3) atoms to form distorted NiTa7Ni4Mo cuboctahedra that share corners with two equivalent Mo(1)Ta6Ni6 cuboctahedra, corners with four equivalent Ni(3)Ta7Ni4Mo cuboctahedra, corners with four equivalent Ni(1)Ta8Ni4 cuboctahedra, corners with five equivalent Ni(2)Ta7Ni4Mo cuboctahedra,  an edgeedge with one Ni(1)Ta8Ni4 cuboctahedra, edges with two equivalent Ni(2)Ta7Ni4Mo cuboctahedra, edges with two equivalent Ni(3)Ta7Ni4Mo cuboctahedra, faces with two equivalent Ni(2)Ta7Ni4Mo cuboctahedra, faces with three equivalent Mo(1)Ta6Ni6 cuboctahedra, and faces with eight equivalent Ni(3)Ta7Ni4Mo cuboctahedra. is represented by the CIF card [CIF]
data_Ta19(Ni9Mo)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.917
_cell_length_b   4.917
_cell_length_c   27.071
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   566.802
_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
  Ta  Ta0  1  0.667  0.333  0.321  1.0
  Ta  Ta1  1  0.000  0.000  0.654  1.0
  Ta  Ta2  1  0.333  0.667  0.988  1.0
  Ta  Ta3  1  0.667  0.333  0.012  1.0
  Ta  Ta4  1  0.000  0.000  0.346  1.0
  Ta  Ta5  1  0.333  0.667  0.679  1.0
  Ta  Ta6  1  0.667  0.333  0.216  1.0
  Ta  Ta7  1  0.000  0.000  0.549  1.0
  Ta  Ta8  1  0.333  0.667  0.882  1.0
  Ta  Ta9  1  0.667  0.333  0.118  1.0
  Ta  Ta10  1  0.000  0.000  0.451  1.0
  Ta  Ta11  1  0.333  0.667  0.784  1.0
  Ta  Ta12  1  0.333  0.667  0.169  1.0
  Ta  Ta13  1  0.667  0.333  0.503  1.0
  Ta  Ta14  1  0.000  0.000  0.836  1.0
  Ta  Ta15  1  0.000  0.000  0.164  1.0
  Ta  Ta16  1  0.333  0.667  0.497  1.0
  Ta  Ta17  1  0.667  0.333  0.831  1.0
  Ta  Ta18  1  0.000  0.000  0.000  1.0
  Ni  Ni19  1  0.169  0.831  0.078  1.0
  Ni  Ni20  1  0.502  0.498  0.411  1.0
  Ni  Ni21  1  0.835  0.165  0.744  1.0
  Ni  Ni22  1  0.661  0.831  0.078  1.0
  Ni  Ni23  1  0.997  0.498  0.411  1.0
  Ni  Ni24  1  0.330  0.165  0.744  1.0
  Ni  Ni25  1  0.169  0.339  0.078  1.0
  Ni  Ni26  1  0.502  0.003  0.411  1.0
  Ni  Ni27  1  0.835  0.670  0.744  1.0
  Ni  Ni28  1  0.165  0.835  0.256  1.0
  Ni  Ni29  1  0.498  0.502  0.589  1.0
  Ni  Ni30  1  0.831  0.169  0.922  1.0
  Ni  Ni31  1  0.670  0.835  0.256  1.0
  Ni  Ni32  1  0.003  0.502  0.589  1.0
  Ni  Ni33  1  0.339  0.169  0.922  1.0
  Ni  Ni34  1  0.165  0.330  0.256  1.0
  Ni  Ni35  1  0.498  0.997  0.589  1.0
  Ni  Ni36  1  0.831  0.661  0.922  1.0
  Mo  Mo37  1  0.333  0.667  0.333  1.0
  Mo  Mo38  1  0.667  0.333  0.667  1.0
[/CIF]
.