The crystal structure described by MgTb4Al2(FeO6)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(12), one O(2), and one O(9) atom to form MgO4 tetrahedra that share  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Al(2)O4 tetrahedra, and corners with two equivalent Fe(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 62°. There are four inequivalent Tb sites. In the first Tb site, Tb(1) is bonded in a 7-coordinate geometry to one O(1), one O(10), one O(11), one O(12), one O(2), one O(5), and one O(6) atom. In the second Tb site, Tb(2) is bonded in a 7-coordinate geometry to one O(1), one O(11), one O(12), one O(2), one O(5), one O(6), and one O(7) atom. In the third Tb site, Tb(3) is bonded in a 7-coordinate geometry to one O(10), one O(3), one O(4), one O(6), one O(7), one O(8), and one O(9) atom. In the fourth Tb site, Tb(4) is bonded in a 7-coordinate geometry to one O(10), one O(11), one O(3), one O(4), one O(7), one O(8), and one O(9) atom. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(12), one O(2), one O(4), one O(5), and one O(8) atom to form distorted FeO5 trigonal bipyramids that share  a cornercorner with one Al(1)O5 square pyramid, corners with two equivalent Mg(1)O4 tetrahedra, and corners with two equivalent Al(2)O4 tetrahedra. In the second Fe site, Fe(2) is bonded to one O(1), one O(10), one O(11), one O(3), one O(6), and one O(7) atom to form FeO6 octahedra that share corners with four equivalent Al(1)O5 square pyramids,  a cornercorner with one Mg(1)O4 tetrahedra, and  a cornercorner with one Al(2)O4 tetrahedra. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(10), one O(11), one O(4), one O(6), and one O(7) atom to form AlO5 square pyramids that share corners with four equivalent Fe(2)O6 octahedra and  a cornercorner with one Fe(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 26-44°. In the second Al site, Al(2) is bonded to one O(3), one O(5), one O(8), and one O(9) atom to form AlO4 tetrahedra that share  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Mg(1)O4 tetrahedra, and corners with two equivalent Fe(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 55°. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Mg(1), one Tb(1), one Tb(2), and one Fe(2) atom. In the second O site, O(2) is bonded to one Mg(1), one Tb(1), one Tb(2), and one Fe(1) atom to form distorted OTb2MgFe trigonal pyramids that share  a cornercorner with one O(8)Tb2AlFe trigonal pyramid,  a cornercorner with one O(9)Tb2MgAl trigonal pyramid, corners with three equivalent O(5)Tb2AlFe trigonal pyramids, and edges with two equivalent O(12)Tb2MgFe tetrahedra. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Tb(3), one Tb(4), one Fe(2), and one Al(2) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Tb(3), one Tb(4), one Fe(1), and one Al(1) atom. In the fifth O site, O(5) is bonded to one Tb(1), one Tb(2), one Fe(1), and one Al(2) atom to form distorted OTb2AlFe trigonal pyramids that share  a cornercorner with one O(12)Tb2MgFe tetrahedra,  a cornercorner with one O(9)Tb2MgAl trigonal pyramid, corners with two equivalent O(8)Tb2AlFe trigonal pyramids, corners with three equivalent O(2)Tb2MgFe trigonal pyramids, and  an edgeedge with one O(12)Tb2MgFe tetrahedra. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one Tb(1), one Tb(2), one Tb(3), one Fe(2), and one Al(1) atom. In the seventh O site, O(7) is bonded in a 5-coordinate geometry to one Tb(2), one Tb(3), one Tb(4), one Fe(2), and one Al(1) atom. In the eighth O site, O(8) is bonded to one Tb(3), one Tb(4), one Fe(1), and one Al(2) atom to form distorted OTb2AlFe trigonal pyramids that share  a cornercorner with one O(12)Tb2MgFe tetrahedra,  a cornercorner with one O(9)Tb2MgAl trigonal pyramid,  a cornercorner with one O(2)Tb2MgFe trigonal pyramid, corners with two equivalent O(5)Tb2AlFe trigonal pyramids, and  an edgeedge with one O(9)Tb2MgAl trigonal pyramid. In the ninth O site, O(9) is bonded to one Mg(1), one Tb(3), one Tb(4), and one Al(2) atom to form distorted OTb2MgAl trigonal pyramids that share  a cornercorner with one O(12)Tb2MgFe tetrahedra,  a cornercorner with one O(5)Tb2AlFe trigonal pyramid,  a cornercorner with one O(8)Tb2AlFe trigonal pyramid,  a cornercorner with one O(2)Tb2MgFe trigonal pyramid, and  an edgeedge with one O(8)Tb2AlFe trigonal pyramid. In the tenth O site, O(10) is bonded in a 5-coordinate geometry to one Tb(1), one Tb(3), one Tb(4), one Fe(2), and one Al(1) atom. In the eleventh O site, O(11) is bonded in a 5-coordinate geometry to one Tb(1), one Tb(2), one Tb(4), one Fe(2), and one Al(1) atom. In the twelfth O site, O(12) is bonded to one Mg(1), one Tb(1), one Tb(2), and one Fe(1) atom to form distorted OTb2MgFe tetrahedra that share  a cornercorner with one O(5)Tb2AlFe trigonal pyramid,  a cornercorner with one O(8)Tb2AlFe trigonal pyramid,  a cornercorner with one O(9)Tb2MgAl trigonal pyramid,  an edgeedge with one O(5)Tb2AlFe trigonal pyramid, and edges with two equivalent O(2)Tb2MgFe trigonal pyramids. is represented by the CIF file [CIF]
data_Tb4MgAl2(FeO6)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.433
_cell_length_b   5.832
_cell_length_c   8.356
_cell_angle_alpha   85.599
_cell_angle_beta   93.899
_cell_angle_gamma   89.043
_symmetry_Int_Tables_number   1
_cell_volume   263.282
_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
  Tb  Tb0  1  0.520  0.629  0.280  1.0
  Tb  Tb1  1  0.932  0.118  0.294  1.0
  Tb  Tb2  1  0.477  0.406  0.731  1.0
  Tb  Tb3  1  0.051  0.918  0.720  1.0
  Mg  Mg4  1  0.383  0.220  0.115  1.0
  Al  Al5  1  0.970  0.508  0.547  1.0
  Al  Al6  1  0.530  0.900  0.918  1.0
  Fe  Fe7  1  0.969  0.547  0.007  1.0
  Fe  Fe8  1  0.487  0.008  0.507  1.0
  O  O9  1  0.329  0.979  0.281  1.0
  O  O10  1  0.173  0.440  0.210  1.0
  O  O11  1  0.656  0.017  0.739  1.0
  O  O12  1  0.873  0.537  0.758  1.0
  O  O13  1  0.746  0.855  0.086  1.0
  O  O14  1  0.704  0.348  0.464  1.0
  O  O15  1  0.165  0.224  0.561  1.0
  O  O16  1  0.329  0.668  0.896  1.0
  O  O17  1  0.294  0.127  0.905  1.0
  O  O18  1  0.265  0.671  0.562  1.0
  O  O19  1  0.813  0.802  0.459  1.0
  O  O20  1  0.694  0.363  0.122  1.0
[/CIF]
.
The crystal structure described by MgTb4Al2(FeO6)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(12), one O(2), and one O(9) atom to form MgO4 tetrahedra that share  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Al(2)O4 tetrahedra, and corners with two equivalent Fe(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 62°. There are four inequivalent Tb sites. In the first Tb site, Tb(1) is bonded in a 7-coordinate geometry to one O(1), one O(10), one O(11), one O(12), one O(2), one O(5), and one O(6) atom. In the second Tb site, Tb(2) is bonded in a 7-coordinate geometry to one O(1), one O(11), one O(12), one O(2), one O(5), one O(6), and one O(7) atom. In the third Tb site, Tb(3) is bonded in a 7-coordinate geometry to one O(10), one O(3), one O(4), one O(6), one O(7), one O(8), and one O(9) atom. In the fourth Tb site, Tb(4) is bonded in a 7-coordinate geometry to one O(10), one O(11), one O(3), one O(4), one O(7), one O(8), and one O(9) atom. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(12), one O(2), one O(4), one O(5), and one O(8) atom to form distorted FeO5 trigonal bipyramids that share  a cornercorner with one Al(1)O5 square pyramid, corners with two equivalent Mg(1)O4 tetrahedra, and corners with two equivalent Al(2)O4 tetrahedra. In the second Fe site, Fe(2) is bonded to one O(1), one O(10), one O(11), one O(3), one O(6), and one O(7) atom to form FeO6 octahedra that share corners with four equivalent Al(1)O5 square pyramids,  a cornercorner with one Mg(1)O4 tetrahedra, and  a cornercorner with one Al(2)O4 tetrahedra. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(10), one O(11), one O(4), one O(6), and one O(7) atom to form AlO5 square pyramids that share corners with four equivalent Fe(2)O6 octahedra and  a cornercorner with one Fe(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 26-44°. In the second Al site, Al(2) is bonded to one O(3), one O(5), one O(8), and one O(9) atom to form AlO4 tetrahedra that share  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Mg(1)O4 tetrahedra, and corners with two equivalent Fe(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 55°. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Mg(1), one Tb(1), one Tb(2), and one Fe(2) atom. In the second O site, O(2) is bonded to one Mg(1), one Tb(1), one Tb(2), and one Fe(1) atom to form distorted OTb2MgFe trigonal pyramids that share  a cornercorner with one O(8)Tb2AlFe trigonal pyramid,  a cornercorner with one O(9)Tb2MgAl trigonal pyramid, corners with three equivalent O(5)Tb2AlFe trigonal pyramids, and edges with two equivalent O(12)Tb2MgFe tetrahedra. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Tb(3), one Tb(4), one Fe(2), and one Al(2) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Tb(3), one Tb(4), one Fe(1), and one Al(1) atom. In the fifth O site, O(5) is bonded to one Tb(1), one Tb(2), one Fe(1), and one Al(2) atom to form distorted OTb2AlFe trigonal pyramids that share  a cornercorner with one O(12)Tb2MgFe tetrahedra,  a cornercorner with one O(9)Tb2MgAl trigonal pyramid, corners with two equivalent O(8)Tb2AlFe trigonal pyramids, corners with three equivalent O(2)Tb2MgFe trigonal pyramids, and  an edgeedge with one O(12)Tb2MgFe tetrahedra. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one Tb(1), one Tb(2), one Tb(3), one Fe(2), and one Al(1) atom. In the seventh O site, O(7) is bonded in a 5-coordinate geometry to one Tb(2), one Tb(3), one Tb(4), one Fe(2), and one Al(1) atom. In the eighth O site, O(8) is bonded to one Tb(3), one Tb(4), one Fe(1), and one Al(2) atom to form distorted OTb2AlFe trigonal pyramids that share  a cornercorner with one O(12)Tb2MgFe tetrahedra,  a cornercorner with one O(9)Tb2MgAl trigonal pyramid,  a cornercorner with one O(2)Tb2MgFe trigonal pyramid, corners with two equivalent O(5)Tb2AlFe trigonal pyramids, and  an edgeedge with one O(9)Tb2MgAl trigonal pyramid. In the ninth O site, O(9) is bonded to one Mg(1), one Tb(3), one Tb(4), and one Al(2) atom to form distorted OTb2MgAl trigonal pyramids that share  a cornercorner with one O(12)Tb2MgFe tetrahedra,  a cornercorner with one O(5)Tb2AlFe trigonal pyramid,  a cornercorner with one O(8)Tb2AlFe trigonal pyramid,  a cornercorner with one O(2)Tb2MgFe trigonal pyramid, and  an edgeedge with one O(8)Tb2AlFe trigonal pyramid. In the tenth O site, O(10) is bonded in a 5-coordinate geometry to one Tb(1), one Tb(3), one Tb(4), one Fe(2), and one Al(1) atom. In the eleventh O site, O(11) is bonded in a 5-coordinate geometry to one Tb(1), one Tb(2), one Tb(4), one Fe(2), and one Al(1) atom. In the twelfth O site, O(12) is bonded to one Mg(1), one Tb(1), one Tb(2), and one Fe(1) atom to form distorted OTb2MgFe tetrahedra that share  a cornercorner with one O(5)Tb2AlFe trigonal pyramid,  a cornercorner with one O(8)Tb2AlFe trigonal pyramid,  a cornercorner with one O(9)Tb2MgAl trigonal pyramid,  an edgeedge with one O(5)Tb2AlFe trigonal pyramid, and edges with two equivalent O(2)Tb2MgFe trigonal pyramids. is represented by the CIF file [CIF]
data_Tb4MgAl2(FeO6)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.433
_cell_length_b   5.832
_cell_length_c   8.356
_cell_angle_alpha   85.599
_cell_angle_beta   93.899
_cell_angle_gamma   89.043
_symmetry_Int_Tables_number   1
_cell_volume   263.282
_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
  Tb  Tb0  1  0.520  0.629  0.280  1.0
  Tb  Tb1  1  0.932  0.118  0.294  1.0
  Tb  Tb2  1  0.477  0.406  0.731  1.0
  Tb  Tb3  1  0.051  0.918  0.720  1.0
  Mg  Mg4  1  0.383  0.220  0.115  1.0
  Al  Al5  1  0.970  0.508  0.547  1.0
  Al  Al6  1  0.530  0.900  0.918  1.0
  Fe  Fe7  1  0.969  0.547  0.007  1.0
  Fe  Fe8  1  0.487  0.008  0.507  1.0
  O  O9  1  0.329  0.979  0.281  1.0
  O  O10  1  0.173  0.440  0.210  1.0
  O  O11  1  0.656  0.017  0.739  1.0
  O  O12  1  0.873  0.537  0.758  1.0
  O  O13  1  0.746  0.855  0.086  1.0
  O  O14  1  0.704  0.348  0.464  1.0
  O  O15  1  0.165  0.224  0.561  1.0
  O  O16  1  0.329  0.668  0.896  1.0
  O  O17  1  0.294  0.127  0.905  1.0
  O  O18  1  0.265  0.671  0.562  1.0
  O  O19  1  0.813  0.802  0.459  1.0
  O  O20  1  0.694  0.363  0.122  1.0
[/CIF]
.