The compound described by Ba2YBr7 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to one Br(1), one Br(2), one Br(3), one Br(4), one Br(5), one Br(6), and one Br(7) atom to form distorted BaBr7 pentagonal bipyramids that share  a cornercorner with one Y(1)Br6 octahedra,  an edgeedge with one Y(1)Br6 octahedra, and  a faceface with one Y(1)Br6 octahedra. The corner-sharing octahedral tilt angles are 49°. In the second Ba site, Ba(2) is bonded in a 7-coordinate geometry to one Br(1), one Br(2), one Br(3), one Br(4), one Br(5), one Br(6), and one Br(7) atom. Y(1) is bonded to one Br(1), one Br(2), one Br(3), one Br(4), one Br(6), and one Br(7) atom to form YBr6 octahedra that share  a cornercorner with one Ba(1)Br7 pentagonal bipyramid,  an edgeedge with one Ba(1)Br7 pentagonal bipyramid, and  a faceface with one Ba(1)Br7 pentagonal bipyramid. There are seven inequivalent Br sites. In the first Br site, Br(1) is bonded in a 3-coordinate geometry to one Ba(1), one Ba(2), and one Y(1) atom. In the second Br site, Br(2) is bonded in a 3-coordinate geometry to one Ba(1), one Ba(2), and one Y(1) atom. In the third Br site, Br(3) is bonded in a distorted trigonal non-coplanar geometry to one Ba(1), one Ba(2), and one Y(1) atom. In the fourth Br site, Br(4) is bonded in a distorted trigonal non-coplanar geometry to one Ba(1), one Ba(2), and one Y(1) atom. In the fifth Br site, Br(5) is bonded in a bent 150 degrees geometry to one Ba(1) and one Ba(2) atom. In the sixth Br site, Br(6) is bonded in a T-shaped geometry to one Ba(1), one Ba(2), and one Y(1) atom. In the seventh Br site, Br(7) is bonded in a distorted T-shaped geometry to one Ba(1), one Ba(2), and one Y(1) atom. is represented by the CIF file [CIF]
data_Ba2YBr7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   13.410
_cell_length_b   8.624
_cell_length_c   16.405
_cell_angle_alpha   60.941
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   1658.322
_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
  Ba  Ba0  1  0.237  0.809  0.477  1.0
  Ba  Ba1  1  0.364  0.414  0.783  1.0
  Ba  Ba2  1  0.864  0.586  0.717  1.0
  Ba  Ba3  1  0.263  0.809  0.977  1.0
  Ba  Ba4  1  0.737  0.191  0.023  1.0
  Ba  Ba5  1  0.136  0.414  0.283  1.0
  Ba  Ba6  1  0.636  0.586  0.217  1.0
  Ba  Ba7  1  0.763  0.191  0.523  1.0
  Y  Y8  1  0.701  0.950  0.323  1.0
  Y  Y9  1  0.799  0.950  0.823  1.0
  Y  Y10  1  0.201  0.050  0.177  1.0
  Y  Y11  1  0.299  0.050  0.677  1.0
  Br  Br12  1  0.559  0.986  0.188  1.0
  Br  Br13  1  0.827  0.851  0.219  1.0
  Br  Br14  1  0.271  0.704  0.313  1.0
  Br  Br15  1  0.409  0.842  0.616  1.0
  Br  Br16  1  0.941  0.986  0.688  1.0
  Br  Br17  1  0.084  0.610  0.639  1.0
  Br  Br18  1  0.816  0.852  0.487  1.0
  Br  Br19  1  0.367  0.409  0.582  1.0
  Br  Br20  1  0.673  0.851  0.719  1.0
  Br  Br21  1  0.229  0.704  0.813  1.0
  Br  Br22  1  0.867  0.591  0.918  1.0
  Br  Br23  1  0.316  0.148  0.013  1.0
  Br  Br24  1  0.584  0.390  0.861  1.0
  Br  Br25  1  0.091  0.842  0.116  1.0
  Br  Br26  1  0.909  0.158  0.884  1.0
  Br  Br27  1  0.416  0.610  0.139  1.0
  Br  Br28  1  0.684  0.852  0.987  1.0
  Br  Br29  1  0.133  0.409  0.082  1.0
  Br  Br30  1  0.771  0.296  0.187  1.0
  Br  Br31  1  0.327  0.149  0.281  1.0
  Br  Br32  1  0.633  0.591  0.418  1.0
  Br  Br33  1  0.184  0.148  0.513  1.0
  Br  Br34  1  0.916  0.390  0.361  1.0
  Br  Br35  1  0.059  0.014  0.312  1.0
  Br  Br36  1  0.591  0.158  0.384  1.0
  Br  Br37  1  0.729  0.296  0.687  1.0
  Br  Br38  1  0.173  0.149  0.781  1.0
  Br  Br39  1  0.441  0.014  0.812  1.0
[/CIF]
.
The compound described by Ba2YBr7 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to one Br(1), one Br(2), one Br(3), one Br(4), one Br(5), one Br(6), and one Br(7) atom to form distorted BaBr7 pentagonal bipyramids that share  a cornercorner with one Y(1)Br6 octahedra,  an edgeedge with one Y(1)Br6 octahedra, and  a faceface with one Y(1)Br6 octahedra. The corner-sharing octahedral tilt angles are 49°. In the second Ba site, Ba(2) is bonded in a 7-coordinate geometry to one Br(1), one Br(2), one Br(3), one Br(4), one Br(5), one Br(6), and one Br(7) atom. Y(1) is bonded to one Br(1), one Br(2), one Br(3), one Br(4), one Br(6), and one Br(7) atom to form YBr6 octahedra that share  a cornercorner with one Ba(1)Br7 pentagonal bipyramid,  an edgeedge with one Ba(1)Br7 pentagonal bipyramid, and  a faceface with one Ba(1)Br7 pentagonal bipyramid. There are seven inequivalent Br sites. In the first Br site, Br(1) is bonded in a 3-coordinate geometry to one Ba(1), one Ba(2), and one Y(1) atom. In the second Br site, Br(2) is bonded in a 3-coordinate geometry to one Ba(1), one Ba(2), and one Y(1) atom. In the third Br site, Br(3) is bonded in a distorted trigonal non-coplanar geometry to one Ba(1), one Ba(2), and one Y(1) atom. In the fourth Br site, Br(4) is bonded in a distorted trigonal non-coplanar geometry to one Ba(1), one Ba(2), and one Y(1) atom. In the fifth Br site, Br(5) is bonded in a bent 150 degrees geometry to one Ba(1) and one Ba(2) atom. In the sixth Br site, Br(6) is bonded in a T-shaped geometry to one Ba(1), one Ba(2), and one Y(1) atom. In the seventh Br site, Br(7) is bonded in a distorted T-shaped geometry to one Ba(1), one Ba(2), and one Y(1) atom. is represented by the CIF file [CIF]
data_Ba2YBr7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   13.410
_cell_length_b   8.624
_cell_length_c   16.405
_cell_angle_alpha   60.941
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   1658.322
_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
  Ba  Ba0  1  0.237  0.809  0.477  1.0
  Ba  Ba1  1  0.364  0.414  0.783  1.0
  Ba  Ba2  1  0.864  0.586  0.717  1.0
  Ba  Ba3  1  0.263  0.809  0.977  1.0
  Ba  Ba4  1  0.737  0.191  0.023  1.0
  Ba  Ba5  1  0.136  0.414  0.283  1.0
  Ba  Ba6  1  0.636  0.586  0.217  1.0
  Ba  Ba7  1  0.763  0.191  0.523  1.0
  Y  Y8  1  0.701  0.950  0.323  1.0
  Y  Y9  1  0.799  0.950  0.823  1.0
  Y  Y10  1  0.201  0.050  0.177  1.0
  Y  Y11  1  0.299  0.050  0.677  1.0
  Br  Br12  1  0.559  0.986  0.188  1.0
  Br  Br13  1  0.827  0.851  0.219  1.0
  Br  Br14  1  0.271  0.704  0.313  1.0
  Br  Br15  1  0.409  0.842  0.616  1.0
  Br  Br16  1  0.941  0.986  0.688  1.0
  Br  Br17  1  0.084  0.610  0.639  1.0
  Br  Br18  1  0.816  0.852  0.487  1.0
  Br  Br19  1  0.367  0.409  0.582  1.0
  Br  Br20  1  0.673  0.851  0.719  1.0
  Br  Br21  1  0.229  0.704  0.813  1.0
  Br  Br22  1  0.867  0.591  0.918  1.0
  Br  Br23  1  0.316  0.148  0.013  1.0
  Br  Br24  1  0.584  0.390  0.861  1.0
  Br  Br25  1  0.091  0.842  0.116  1.0
  Br  Br26  1  0.909  0.158  0.884  1.0
  Br  Br27  1  0.416  0.610  0.139  1.0
  Br  Br28  1  0.684  0.852  0.987  1.0
  Br  Br29  1  0.133  0.409  0.082  1.0
  Br  Br30  1  0.771  0.296  0.187  1.0
  Br  Br31  1  0.327  0.149  0.281  1.0
  Br  Br32  1  0.633  0.591  0.418  1.0
  Br  Br33  1  0.184  0.148  0.513  1.0
  Br  Br34  1  0.916  0.390  0.361  1.0
  Br  Br35  1  0.059  0.014  0.312  1.0
  Br  Br36  1  0.591  0.158  0.384  1.0
  Br  Br37  1  0.729  0.296  0.687  1.0
  Br  Br38  1  0.173  0.149  0.781  1.0
  Br  Br39  1  0.441  0.014  0.812  1.0
[/CIF]
.