The crystal structure described by MgY2Bi2O7 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(2), one O(4), one O(6), and one O(7) atom to form MgO5 trigonal bipyramids that share  a cornercorner with one Bi(2)O5 square pyramid, edges with two equivalent Y(1)O6 pentagonal pyramids, and  an edgeedge with one Bi(2)O5 square pyramid. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded to one O(1), one O(2), one O(3), one O(5), one O(6), and one O(7) atom to form distorted YO6 pentagonal pyramids that share corners with two equivalent Bi(2)O5 square pyramids,  an edgeedge with one Bi(2)O5 square pyramid, and edges with two equivalent Mg(1)O5 trigonal bipyramids. In the second Y site, Y(2) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(5), one O(6), and one O(7) atom. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a distorted rectangular see-saw-like geometry to one O(1), one O(3), one O(4), and one O(5) atom. In the second Bi site, Bi(2) is bonded to one O(3), one O(4), one O(5), one O(6), and one O(7) atom to form distorted BiO5 square pyramids that share corners with two equivalent Y(1)O6 pentagonal pyramids,  a cornercorner with one Mg(1)O5 trigonal bipyramid,  an edgeedge with one Y(1)O6 pentagonal pyramid, and  an edgeedge with one Mg(1)O5 trigonal bipyramid. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Y(1), one Y(2), and one Bi(1) atom. In the second O site, O(2) is bonded in a T-shaped geometry to one Mg(1), one Y(1), and one Y(2) atom. In the third O site, O(3) is bonded to one Y(1), one Y(2), one Bi(1), and one Bi(2) atom to form edge-sharing OY2Bi2 tetrahedra. In the fourth O site, O(4) is bonded in a T-shaped geometry to one Mg(1), one Bi(1), and one Bi(2) atom. In the fifth O site, O(5) is bonded to one Y(1), one Y(2), one Bi(1), and one Bi(2) atom to form edge-sharing OY2Bi2 tetrahedra. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Mg(1), one Y(1), one Y(2), and one Bi(2) atom. In the seventh O site, O(7) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Y(1), one Y(2), and one Bi(2) atom. is represented by the CIF card [CIF]
data_Y2MgBi2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.549
_cell_length_b   6.317
_cell_length_c   5.698
_cell_angle_alpha   71.886
_cell_angle_beta   103.322
_cell_angle_gamma   67.499
_symmetry_Int_Tables_number   1
_cell_volume   189.870
_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
  Y  Y0  1  0.666  0.668  0.981  1.0
  Y  Y1  1  0.309  0.334  0.095  1.0
  Mg  Mg2  1  0.799  0.771  0.469  1.0
  Bi  Bi3  1  0.230  0.802  0.370  1.0
  Bi  Bi4  1  0.754  0.179  0.713  1.0
  O  O5  1  0.026  0.618  0.252  1.0
  O  O6  1  0.529  0.974  0.100  1.0
  O  O7  1  0.442  0.512  0.780  1.0
  O  O8  1  0.972  0.961  0.536  1.0
  O  O9  1  0.542  0.481  0.307  1.0
  O  O10  1  0.935  0.454  0.823  1.0
  O  O11  1  0.534  0.996  0.572  1.0
[/CIF]
.
The crystal structure described by MgY2Bi2O7 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(2), one O(4), one O(6), and one O(7) atom to form MgO5 trigonal bipyramids that share  a cornercorner with one Bi(2)O5 square pyramid, edges with two equivalent Y(1)O6 pentagonal pyramids, and  an edgeedge with one Bi(2)O5 square pyramid. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded to one O(1), one O(2), one O(3), one O(5), one O(6), and one O(7) atom to form distorted YO6 pentagonal pyramids that share corners with two equivalent Bi(2)O5 square pyramids,  an edgeedge with one Bi(2)O5 square pyramid, and edges with two equivalent Mg(1)O5 trigonal bipyramids. In the second Y site, Y(2) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(5), one O(6), and one O(7) atom. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a distorted rectangular see-saw-like geometry to one O(1), one O(3), one O(4), and one O(5) atom. In the second Bi site, Bi(2) is bonded to one O(3), one O(4), one O(5), one O(6), and one O(7) atom to form distorted BiO5 square pyramids that share corners with two equivalent Y(1)O6 pentagonal pyramids,  a cornercorner with one Mg(1)O5 trigonal bipyramid,  an edgeedge with one Y(1)O6 pentagonal pyramid, and  an edgeedge with one Mg(1)O5 trigonal bipyramid. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Y(1), one Y(2), and one Bi(1) atom. In the second O site, O(2) is bonded in a T-shaped geometry to one Mg(1), one Y(1), and one Y(2) atom. In the third O site, O(3) is bonded to one Y(1), one Y(2), one Bi(1), and one Bi(2) atom to form edge-sharing OY2Bi2 tetrahedra. In the fourth O site, O(4) is bonded in a T-shaped geometry to one Mg(1), one Bi(1), and one Bi(2) atom. In the fifth O site, O(5) is bonded to one Y(1), one Y(2), one Bi(1), and one Bi(2) atom to form edge-sharing OY2Bi2 tetrahedra. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Mg(1), one Y(1), one Y(2), and one Bi(2) atom. In the seventh O site, O(7) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Y(1), one Y(2), and one Bi(2) atom. is represented by the CIF card [CIF]
data_Y2MgBi2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.549
_cell_length_b   6.317
_cell_length_c   5.698
_cell_angle_alpha   71.886
_cell_angle_beta   103.322
_cell_angle_gamma   67.499
_symmetry_Int_Tables_number   1
_cell_volume   189.870
_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
  Y  Y0  1  0.666  0.668  0.981  1.0
  Y  Y1  1  0.309  0.334  0.095  1.0
  Mg  Mg2  1  0.799  0.771  0.469  1.0
  Bi  Bi3  1  0.230  0.802  0.370  1.0
  Bi  Bi4  1  0.754  0.179  0.713  1.0
  O  O5  1  0.026  0.618  0.252  1.0
  O  O6  1  0.529  0.974  0.100  1.0
  O  O7  1  0.442  0.512  0.780  1.0
  O  O8  1  0.972  0.961  0.536  1.0
  O  O9  1  0.542  0.481  0.307  1.0
  O  O10  1  0.935  0.454  0.823  1.0
  O  O11  1  0.534  0.996  0.572  1.0
[/CIF]
.