The structure described by Y2Al(BeB)O7 crystallizes in the monoclinic P2_1 space group. Be(1) is bonded to one O(2), one O(3), one O(5), and one O(7) atom to form BeO4 tetrahedra that share  a cornercorner with one B(1)O4 tetrahedra and corners with two equivalent Al(1)O4 tetrahedra. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded in a 8-coordinate geometry to one O(3), one O(4), one O(6), one O(7), two equivalent O(2), and two equivalent O(5) atoms. In the second Y site, Y(2) is bonded in a 8-coordinate geometry to one O(3), one O(4), one O(5), one O(7), two equivalent O(1), and two equivalent O(6) atoms. Al(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form AlO4 tetrahedra that share corners with two equivalent Be(1)O4 tetrahedra and corners with two equivalent B(1)O4 tetrahedra. B(1) is bonded to one O(1), one O(4), one O(6), and one O(7) atom to form BO4 tetrahedra that share  a cornercorner with one Be(1)O4 tetrahedra and corners with two equivalent Al(1)O4 tetrahedra. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Y(2), one Al(1), and one B(1) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Be(1), two equivalent Y(1), and one Al(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Be(1), one Y(1), one Y(2), and one Al(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Y(1), one Y(2), one Al(1), and one B(1) atom. In the fifth O site, O(5) is bonded to one Be(1), one Y(2), and two equivalent Y(1) atoms to form distorted corner-sharing OY3Be tetrahedra. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one Y(1), two equivalent Y(2), and one B(1) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Be(1), one Y(1), one Y(2), and one B(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Y2BeAlBO7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.379
_cell_length_b   4.755
_cell_length_c   7.386
_cell_angle_alpha   89.739
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   259.143
_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
  Y  Y0  1  0.662  0.508  0.578  1.0
  Y  Y1  1  0.162  0.492  0.422  1.0
  Y  Y2  1  0.335  0.506  0.904  1.0
  Y  Y3  1  0.835  0.494  0.096  1.0
  Be  Be4  1  0.865  0.945  0.386  1.0
  Be  Be5  1  0.365  0.055  0.614  1.0
  Al  Al6  1  0.498  0.000  0.248  1.0
  Al  Al7  1  0.998  1.000  0.752  1.0
  B  B8  1  0.136  0.936  0.114  1.0
  B  B9  1  0.636  0.064  0.886  1.0
  O  O10  1  0.581  0.207  0.064  1.0
  O  O11  1  0.081  0.793  0.936  1.0
  O  O12  1  0.423  0.220  0.422  1.0
  O  O13  1  0.923  0.780  0.578  1.0
  O  O14  1  0.673  0.778  0.321  1.0
  O  O15  1  0.173  0.222  0.679  1.0
  O  O16  1  0.316  0.795  0.162  1.0
  O  O17  1  0.816  0.205  0.838  1.0
  O  O18  1  0.860  0.279  0.386  1.0
  O  O19  1  0.360  0.721  0.614  1.0
  O  O20  1  0.142  0.241  0.105  1.0
  O  O21  1  0.642  0.759  0.895  1.0
  O  O22  1  0.509  0.180  0.755  1.0
  O  O23  1  0.009  0.820  0.245  1.0
[/CIF]
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The structure described by Y2Al(BeB)O7 crystallizes in the monoclinic P2_1 space group. Be(1) is bonded to one O(2), one O(3), one O(5), and one O(7) atom to form BeO4 tetrahedra that share  a cornercorner with one B(1)O4 tetrahedra and corners with two equivalent Al(1)O4 tetrahedra. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded in a 8-coordinate geometry to one O(3), one O(4), one O(6), one O(7), two equivalent O(2), and two equivalent O(5) atoms. In the second Y site, Y(2) is bonded in a 8-coordinate geometry to one O(3), one O(4), one O(5), one O(7), two equivalent O(1), and two equivalent O(6) atoms. Al(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form AlO4 tetrahedra that share corners with two equivalent Be(1)O4 tetrahedra and corners with two equivalent B(1)O4 tetrahedra. B(1) is bonded to one O(1), one O(4), one O(6), and one O(7) atom to form BO4 tetrahedra that share  a cornercorner with one Be(1)O4 tetrahedra and corners with two equivalent Al(1)O4 tetrahedra. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Y(2), one Al(1), and one B(1) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Be(1), two equivalent Y(1), and one Al(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Be(1), one Y(1), one Y(2), and one Al(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Y(1), one Y(2), one Al(1), and one B(1) atom. In the fifth O site, O(5) is bonded to one Be(1), one Y(2), and two equivalent Y(1) atoms to form distorted corner-sharing OY3Be tetrahedra. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one Y(1), two equivalent Y(2), and one B(1) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Be(1), one Y(1), one Y(2), and one B(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Y2BeAlBO7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.379
_cell_length_b   4.755
_cell_length_c   7.386
_cell_angle_alpha   89.739
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   259.143
_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
  Y  Y0  1  0.662  0.508  0.578  1.0
  Y  Y1  1  0.162  0.492  0.422  1.0
  Y  Y2  1  0.335  0.506  0.904  1.0
  Y  Y3  1  0.835  0.494  0.096  1.0
  Be  Be4  1  0.865  0.945  0.386  1.0
  Be  Be5  1  0.365  0.055  0.614  1.0
  Al  Al6  1  0.498  0.000  0.248  1.0
  Al  Al7  1  0.998  1.000  0.752  1.0
  B  B8  1  0.136  0.936  0.114  1.0
  B  B9  1  0.636  0.064  0.886  1.0
  O  O10  1  0.581  0.207  0.064  1.0
  O  O11  1  0.081  0.793  0.936  1.0
  O  O12  1  0.423  0.220  0.422  1.0
  O  O13  1  0.923  0.780  0.578  1.0
  O  O14  1  0.673  0.778  0.321  1.0
  O  O15  1  0.173  0.222  0.679  1.0
  O  O16  1  0.316  0.795  0.162  1.0
  O  O17  1  0.816  0.205  0.838  1.0
  O  O18  1  0.860  0.279  0.386  1.0
  O  O19  1  0.360  0.721  0.614  1.0
  O  O20  1  0.142  0.241  0.105  1.0
  O  O21  1  0.642  0.759  0.895  1.0
  O  O22  1  0.509  0.180  0.755  1.0
  O  O23  1  0.009  0.820  0.245  1.0
[/CIF]
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