The structure described by UMnAl is Frank-Kasper $\mu$ Phase-derived structured and crystallizes in the orthorhombic Amm2 space group. There are five inequivalent U sites. In the first U site, U(1) is bonded in a 16-coordinate geometry to one U(1); three U(2,2); one Mn(3); two equivalent Mn(1); two equivalent Mn(2); three equivalent Al(1); and four equivalent Al(2) atoms. In the second U site, U(2) is bonded in a 16-coordinate geometry to one U(2), three equivalent U(1), one Mn(1), two equivalent Mn(3), four equivalent Mn(2), two equivalent Al(2), and three equivalent Al(1) atoms. In the third U site, U(1) is bonded in a 16-coordinate geometry to one U(1), three equivalent U(2), one Mn(3), two equivalent Mn(1), two equivalent Mn(2), three equivalent Al(1), and four equivalent Al(2) atoms. In the fourth U site, U(2) is bonded in a 16-coordinate geometry to one U(2), three equivalent U(1), one Mn(1), two equivalent Mn(3), four equivalent Mn(2), two equivalent Al(2), and three equivalent Al(1) atoms. In the fifth U site, U(1) is bonded in a 16-coordinate geometry to one U(1), three equivalent U(2), one Mn(3), two equivalent Mn(1), two equivalent Mn(2), three equivalent Al(1), and four equivalent Al(2) atoms. There are three inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to two equivalent U(2); four U(1,1); two equivalent Al(1); and four equivalent Al(2) atoms to form MnU6Al6 cuboctahedra that share corners with two equivalent Mn(3)U6Mn4Al2 cuboctahedra, corners with four equivalent Mn(1)U6Al6 cuboctahedra, corners with four equivalent Al(1)U6Mn4Al2 cuboctahedra, corners with eight equivalent Mn(2)U6Mn4Al2 cuboctahedra, edges with two equivalent Mn(1)U6Al6 cuboctahedra, edges with four equivalent Mn(3)U6Mn4Al2 cuboctahedra, faces with four equivalent Mn(2)U6Mn4Al2 cuboctahedra, faces with six equivalent Al(1)U6Mn4Al2 cuboctahedra, and faces with eight equivalent Al(2)U6Mn2Al4 cuboctahedra. In the second Mn site, Mn(2) is bonded to two U(1,1); four U(2,2); two equivalent Mn(2); two equivalent Mn(3); and two equivalent Al(1) atoms to form distorted MnU6Mn4Al2 cuboctahedra that share corners with four equivalent Mn(1)U6Al6 cuboctahedra, corners with four equivalent Mn(2)U6Mn4Al2 cuboctahedra, corners with four equivalent Al(1)U6Mn4Al2 cuboctahedra, corners with six equivalent Al(2)U6Mn2Al4 cuboctahedra, edges with two equivalent Mn(2)U6Mn4Al2 cuboctahedra, edges with four equivalent Al(2)U6Mn2Al4 cuboctahedra, faces with two equivalent Mn(1)U6Al6 cuboctahedra, faces with two equivalent Al(2)U6Mn2Al4 cuboctahedra, faces with four equivalent Mn(2)U6Mn4Al2 cuboctahedra, faces with four equivalent Mn(3)U6Mn4Al2 cuboctahedra, and faces with six equivalent Al(1)U6Mn4Al2 cuboctahedra. In the third Mn site, Mn(3) is bonded to two U(1,1); four equivalent U(2); four equivalent Mn(2); and two equivalent Al(1) atoms to form distorted MnU6Mn4Al2 cuboctahedra that share corners with two equivalent Mn(1)U6Al6 cuboctahedra, corners with four equivalent Mn(3)U6Mn4Al2 cuboctahedra, corners with four equivalent Al(1)U6Mn4Al2 cuboctahedra, corners with eight equivalent Al(2)U6Mn2Al4 cuboctahedra, edges with two equivalent Mn(3)U6Mn4Al2 cuboctahedra, edges with four equivalent Mn(1)U6Al6 cuboctahedra, faces with four equivalent Al(2)U6Mn2Al4 cuboctahedra, faces with six equivalent Al(1)U6Mn4Al2 cuboctahedra, and faces with eight equivalent Mn(2)U6Mn4Al2 cuboctahedra. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to three equivalent U(1); three U(2,2); one Mn(1); one Mn(3); two equivalent Mn(2); and two equivalent Al(2) atoms to form distorted AlU6Mn4Al2 cuboctahedra that share corners with two equivalent Mn(1)U6Al6 cuboctahedra, corners with two equivalent Mn(3)U6Mn4Al2 cuboctahedra, corners with four equivalent Mn(2)U6Mn4Al2 cuboctahedra, corners with four equivalent Al(2)U6Mn2Al4 cuboctahedra, edges with six equivalent Al(1)U6Mn4Al2 cuboctahedra, faces with two equivalent Al(1)U6Mn4Al2 cuboctahedra, faces with three equivalent Mn(1)U6Al6 cuboctahedra, faces with three equivalent Mn(3)U6Mn4Al2 cuboctahedra, faces with six equivalent Mn(2)U6Mn4Al2 cuboctahedra, and faces with six equivalent Al(2)U6Mn2Al4 cuboctahedra. In the second Al site, Al(2) is bonded to two equivalent U(2); four U(1,1,1); two equivalent Mn(1); two equivalent Al(1); and two equivalent Al(2) atoms to form AlU6Mn2Al4 cuboctahedra that share corners with four equivalent Mn(3)U6Mn4Al2 cuboctahedra, corners with four equivalent Al(2)U6Mn2Al4 cuboctahedra, corners with four equivalent Al(1)U6Mn4Al2 cuboctahedra, corners with six equivalent Mn(2)U6Mn4Al2 cuboctahedra, edges with two equivalent Al(2)U6Mn2Al4 cuboctahedra, edges with four equivalent Mn(2)U6Mn4Al2 cuboctahedra, faces with two equivalent Mn(2)U6Mn4Al2 cuboctahedra, faces with two equivalent Mn(3)U6Mn4Al2 cuboctahedra, faces with four equivalent Mn(1)U6Al6 cuboctahedra, faces with four equivalent Al(2)U6Mn2Al4 cuboctahedra, and faces with six equivalent Al(1)U6Mn4Al2 cuboctahedra. is represented by the CIF file [CIF]
data_UMnAl
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.335
_cell_length_b   5.335
_cell_length_c   8.172
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.669
_symmetry_Int_Tables_number   1
_cell_volume   200.050
_cell_formula_units_Z   4
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
  U  U0  1  0.331  0.669  0.195  1.0
  U  U1  1  0.673  0.327  0.337  1.0
  U  U2  1  0.673  0.327  0.663  1.0
  U  U3  1  0.331  0.669  0.805  1.0
  Mn  Mn4  1  0.828  0.172  0.000  1.0
  Mn  Mn5  1  0.174  0.346  0.500  1.0
  Mn  Mn6  1  0.654  0.826  0.500  1.0
  Mn  Mn7  1  0.170  0.830  0.500  1.0
  Al  Al8  1  0.997  0.003  0.259  1.0
  Al  Al9  1  0.997  0.003  0.741  1.0
  Al  Al10  1  0.830  0.660  0.000  1.0
  Al  Al11  1  0.340  0.170  0.000  1.0
[/CIF]
.
The structure described by UMnAl is Frank-Kasper $\mu$ Phase-derived structured and crystallizes in the orthorhombic Amm2 space group. There are five inequivalent U sites. In the first U site, U(1) is bonded in a 16-coordinate geometry to one U(1); three U(2,2); one Mn(3); two equivalent Mn(1); two equivalent Mn(2); three equivalent Al(1); and four equivalent Al(2) atoms. In the second U site, U(2) is bonded in a 16-coordinate geometry to one U(2), three equivalent U(1), one Mn(1), two equivalent Mn(3), four equivalent Mn(2), two equivalent Al(2), and three equivalent Al(1) atoms. In the third U site, U(1) is bonded in a 16-coordinate geometry to one U(1), three equivalent U(2), one Mn(3), two equivalent Mn(1), two equivalent Mn(2), three equivalent Al(1), and four equivalent Al(2) atoms. In the fourth U site, U(2) is bonded in a 16-coordinate geometry to one U(2), three equivalent U(1), one Mn(1), two equivalent Mn(3), four equivalent Mn(2), two equivalent Al(2), and three equivalent Al(1) atoms. In the fifth U site, U(1) is bonded in a 16-coordinate geometry to one U(1), three equivalent U(2), one Mn(3), two equivalent Mn(1), two equivalent Mn(2), three equivalent Al(1), and four equivalent Al(2) atoms. There are three inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to two equivalent U(2); four U(1,1); two equivalent Al(1); and four equivalent Al(2) atoms to form MnU6Al6 cuboctahedra that share corners with two equivalent Mn(3)U6Mn4Al2 cuboctahedra, corners with four equivalent Mn(1)U6Al6 cuboctahedra, corners with four equivalent Al(1)U6Mn4Al2 cuboctahedra, corners with eight equivalent Mn(2)U6Mn4Al2 cuboctahedra, edges with two equivalent Mn(1)U6Al6 cuboctahedra, edges with four equivalent Mn(3)U6Mn4Al2 cuboctahedra, faces with four equivalent Mn(2)U6Mn4Al2 cuboctahedra, faces with six equivalent Al(1)U6Mn4Al2 cuboctahedra, and faces with eight equivalent Al(2)U6Mn2Al4 cuboctahedra. In the second Mn site, Mn(2) is bonded to two U(1,1); four U(2,2); two equivalent Mn(2); two equivalent Mn(3); and two equivalent Al(1) atoms to form distorted MnU6Mn4Al2 cuboctahedra that share corners with four equivalent Mn(1)U6Al6 cuboctahedra, corners with four equivalent Mn(2)U6Mn4Al2 cuboctahedra, corners with four equivalent Al(1)U6Mn4Al2 cuboctahedra, corners with six equivalent Al(2)U6Mn2Al4 cuboctahedra, edges with two equivalent Mn(2)U6Mn4Al2 cuboctahedra, edges with four equivalent Al(2)U6Mn2Al4 cuboctahedra, faces with two equivalent Mn(1)U6Al6 cuboctahedra, faces with two equivalent Al(2)U6Mn2Al4 cuboctahedra, faces with four equivalent Mn(2)U6Mn4Al2 cuboctahedra, faces with four equivalent Mn(3)U6Mn4Al2 cuboctahedra, and faces with six equivalent Al(1)U6Mn4Al2 cuboctahedra. In the third Mn site, Mn(3) is bonded to two U(1,1); four equivalent U(2); four equivalent Mn(2); and two equivalent Al(1) atoms to form distorted MnU6Mn4Al2 cuboctahedra that share corners with two equivalent Mn(1)U6Al6 cuboctahedra, corners with four equivalent Mn(3)U6Mn4Al2 cuboctahedra, corners with four equivalent Al(1)U6Mn4Al2 cuboctahedra, corners with eight equivalent Al(2)U6Mn2Al4 cuboctahedra, edges with two equivalent Mn(3)U6Mn4Al2 cuboctahedra, edges with four equivalent Mn(1)U6Al6 cuboctahedra, faces with four equivalent Al(2)U6Mn2Al4 cuboctahedra, faces with six equivalent Al(1)U6Mn4Al2 cuboctahedra, and faces with eight equivalent Mn(2)U6Mn4Al2 cuboctahedra. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to three equivalent U(1); three U(2,2); one Mn(1); one Mn(3); two equivalent Mn(2); and two equivalent Al(2) atoms to form distorted AlU6Mn4Al2 cuboctahedra that share corners with two equivalent Mn(1)U6Al6 cuboctahedra, corners with two equivalent Mn(3)U6Mn4Al2 cuboctahedra, corners with four equivalent Mn(2)U6Mn4Al2 cuboctahedra, corners with four equivalent Al(2)U6Mn2Al4 cuboctahedra, edges with six equivalent Al(1)U6Mn4Al2 cuboctahedra, faces with two equivalent Al(1)U6Mn4Al2 cuboctahedra, faces with three equivalent Mn(1)U6Al6 cuboctahedra, faces with three equivalent Mn(3)U6Mn4Al2 cuboctahedra, faces with six equivalent Mn(2)U6Mn4Al2 cuboctahedra, and faces with six equivalent Al(2)U6Mn2Al4 cuboctahedra. In the second Al site, Al(2) is bonded to two equivalent U(2); four U(1,1,1); two equivalent Mn(1); two equivalent Al(1); and two equivalent Al(2) atoms to form AlU6Mn2Al4 cuboctahedra that share corners with four equivalent Mn(3)U6Mn4Al2 cuboctahedra, corners with four equivalent Al(2)U6Mn2Al4 cuboctahedra, corners with four equivalent Al(1)U6Mn4Al2 cuboctahedra, corners with six equivalent Mn(2)U6Mn4Al2 cuboctahedra, edges with two equivalent Al(2)U6Mn2Al4 cuboctahedra, edges with four equivalent Mn(2)U6Mn4Al2 cuboctahedra, faces with two equivalent Mn(2)U6Mn4Al2 cuboctahedra, faces with two equivalent Mn(3)U6Mn4Al2 cuboctahedra, faces with four equivalent Mn(1)U6Al6 cuboctahedra, faces with four equivalent Al(2)U6Mn2Al4 cuboctahedra, and faces with six equivalent Al(1)U6Mn4Al2 cuboctahedra. is represented by the CIF file [CIF]
data_UMnAl
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.335
_cell_length_b   5.335
_cell_length_c   8.172
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.669
_symmetry_Int_Tables_number   1
_cell_volume   200.050
_cell_formula_units_Z   4
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
  U  U0  1  0.331  0.669  0.195  1.0
  U  U1  1  0.673  0.327  0.337  1.0
  U  U2  1  0.673  0.327  0.663  1.0
  U  U3  1  0.331  0.669  0.805  1.0
  Mn  Mn4  1  0.828  0.172  0.000  1.0
  Mn  Mn5  1  0.174  0.346  0.500  1.0
  Mn  Mn6  1  0.654  0.826  0.500  1.0
  Mn  Mn7  1  0.170  0.830  0.500  1.0
  Al  Al8  1  0.997  0.003  0.259  1.0
  Al  Al9  1  0.997  0.003  0.741  1.0
  Al  Al10  1  0.830  0.660  0.000  1.0
  Al  Al11  1  0.340  0.170  0.000  1.0
[/CIF]
.