The material described by Ba2Y2Co4O9 crystallizes in the triclinic P1 space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 10-coordinate geometry to one O(8), one O(9), two equivalent O(1), two equivalent O(2), two equivalent O(5), and two equivalent O(6) atoms. In the second Ba site, Ba(2) is bonded in a 10-coordinate geometry to one O(8), one O(9), two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded to one O(7), one O(8), one O(9), two equivalent O(3), and two equivalent O(6) atoms to form distorted YO7 pentagonal bipyramids that share  a cornercorner with one Y(2)O7 pentagonal bipyramid,  an edgeedge with one Y(2)O7 pentagonal bipyramid, edges with two equivalent Y(1)O7 pentagonal bipyramids, edges with two equivalent Co(1)O5 trigonal bipyramids, and edges with two equivalent Co(3)O5 trigonal bipyramids. In the second Y site, Y(2) is bonded to one O(7), one O(8), one O(9), two equivalent O(4), and two equivalent O(5) atoms to form distorted YO7 pentagonal bipyramids that share  a cornercorner with one Y(1)O7 pentagonal bipyramid,  an edgeedge with one Y(1)O7 pentagonal bipyramid, edges with two equivalent Y(2)O7 pentagonal bipyramids, edges with two equivalent Co(1)O5 trigonal bipyramids, and edges with two equivalent Co(3)O5 trigonal bipyramids. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(1), one O(3), one O(5), and two equivalent O(8) atoms to form distorted CoO5 trigonal bipyramids that share corners with two equivalent Co(1)O5 trigonal bipyramids, corners with two equivalent Co(3)O5 trigonal bipyramids, edges with two equivalent Y(1)O7 pentagonal bipyramids, and edges with two equivalent Y(2)O7 pentagonal bipyramids. In the second Co site, Co(2) is bonded in a 5-coordinate geometry to one O(2), one O(4), one O(6), and two equivalent O(9) atoms. In the third Co site, Co(3) is bonded to one O(2), one O(3), one O(5), and two equivalent O(7) atoms to form CoO5 trigonal bipyramids that share corners with two equivalent Co(1)O5 trigonal bipyramids, corners with two equivalent Co(3)O5 trigonal bipyramids, edges with two equivalent Y(1)O7 pentagonal bipyramids, and edges with two equivalent Y(2)O7 pentagonal bipyramids. In the fourth Co site, Co(4) is bonded in a distorted T-shaped geometry to one O(1), one O(4), and one O(6) atom. There are nine inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ba(1), two equivalent Ba(2), one Co(1), and one Co(4) atom to form distorted OBa4Co2 octahedra that share corners with two equivalent O(3)Ba2Y2Co2 octahedra, corners with four equivalent O(2)Ba4Co2 octahedra, edges with two equivalent O(1)Ba4Co2 octahedra, edges with two equivalent O(2)Ba4Co2 octahedra, and  a faceface with one O(3)Ba2Y2Co2 octahedra. The corner-sharing octahedral tilt angles range from 3-59°. In the second O site, O(2) is bonded to two equivalent Ba(1), two equivalent Ba(2), one Co(2), and one Co(3) atom to form distorted OBa4Co2 octahedra that share corners with two equivalent O(3)Ba2Y2Co2 octahedra, corners with four equivalent O(1)Ba4Co2 octahedra, edges with two equivalent O(1)Ba4Co2 octahedra, edges with two equivalent O(2)Ba4Co2 octahedra, and  a faceface with one O(3)Ba2Y2Co2 octahedra. The corner-sharing octahedral tilt angles range from 3-65°. In the third O site, O(3) is bonded to two equivalent Ba(2), two equivalent Y(1), one Co(1), and one Co(3) atom to form distorted OBa2Y2Co2 octahedra that share corners with two equivalent O(1)Ba4Co2 octahedra, corners with two equivalent O(2)Ba4Co2 octahedra, edges with two equivalent O(3)Ba2Y2Co2 octahedra,  a faceface with one O(1)Ba4Co2 octahedra, and  a faceface with one O(2)Ba4Co2 octahedra. The corner-sharing octahedral tilt angles range from 59-65°. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to two equivalent Ba(2), two equivalent Y(2), one Co(2), and one Co(4) atom. In the fifth O site, O(5) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Y(2), one Co(1), and one Co(3) atom. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Y(1), one Co(2), and one Co(4) atom. In the seventh O site, O(7) is bonded in a distorted see-saw-like geometry to one Y(1), one Y(2), and two equivalent Co(3) atoms. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one Ba(1), one Ba(2), one Y(1), one Y(2), and two equivalent Co(1) atoms. In the ninth O site, O(9) is bonded in a 4-coordinate geometry to one Ba(1), one Ba(2), one Y(1), one Y(2), and two equivalent Co(2) atoms. is represented by the CIF card [CIF]
data_Ba2Y2Co4O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.742
_cell_length_b   8.302
_cell_length_c   8.795
_cell_angle_alpha   118.483
_cell_angle_beta   90.045
_cell_angle_gamma   90.005
_symmetry_Int_Tables_number   1
_cell_volume   240.169
_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
  Ba  Ba0  1  0.999  0.989  0.494  1.0
  Ba  Ba1  1  0.000  0.489  0.482  1.0
  Y  Y2  1  0.001  0.236  0.008  1.0
  Y  Y3  1  1.000  0.773  0.010  1.0
  Co  Co4  1  0.500  0.122  0.253  1.0
  Co  Co5  1  0.500  0.858  0.741  1.0
  Co  Co6  1  0.500  0.603  0.211  1.0
  Co  Co7  1  0.500  0.382  0.759  1.0
  O  O8  1  0.500  0.260  0.512  1.0
  O  O9  1  0.500  0.745  0.487  1.0
  O  O10  1  0.500  0.352  0.198  1.0
  O  O11  1  0.500  0.632  0.813  1.0
  O  O12  1  0.500  0.852  0.197  1.0
  O  O13  1  0.501  0.194  0.817  1.0
  O  O14  1  0.000  0.548  0.090  1.0
  O  O15  1  1.000  0.090  0.173  1.0
  O  O16  1  0.000  0.911  0.819  1.0
[/CIF]
.
The material described by Ba2Y2Co4O9 crystallizes in the triclinic P1 space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 10-coordinate geometry to one O(8), one O(9), two equivalent O(1), two equivalent O(2), two equivalent O(5), and two equivalent O(6) atoms. In the second Ba site, Ba(2) is bonded in a 10-coordinate geometry to one O(8), one O(9), two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded to one O(7), one O(8), one O(9), two equivalent O(3), and two equivalent O(6) atoms to form distorted YO7 pentagonal bipyramids that share  a cornercorner with one Y(2)O7 pentagonal bipyramid,  an edgeedge with one Y(2)O7 pentagonal bipyramid, edges with two equivalent Y(1)O7 pentagonal bipyramids, edges with two equivalent Co(1)O5 trigonal bipyramids, and edges with two equivalent Co(3)O5 trigonal bipyramids. In the second Y site, Y(2) is bonded to one O(7), one O(8), one O(9), two equivalent O(4), and two equivalent O(5) atoms to form distorted YO7 pentagonal bipyramids that share  a cornercorner with one Y(1)O7 pentagonal bipyramid,  an edgeedge with one Y(1)O7 pentagonal bipyramid, edges with two equivalent Y(2)O7 pentagonal bipyramids, edges with two equivalent Co(1)O5 trigonal bipyramids, and edges with two equivalent Co(3)O5 trigonal bipyramids. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(1), one O(3), one O(5), and two equivalent O(8) atoms to form distorted CoO5 trigonal bipyramids that share corners with two equivalent Co(1)O5 trigonal bipyramids, corners with two equivalent Co(3)O5 trigonal bipyramids, edges with two equivalent Y(1)O7 pentagonal bipyramids, and edges with two equivalent Y(2)O7 pentagonal bipyramids. In the second Co site, Co(2) is bonded in a 5-coordinate geometry to one O(2), one O(4), one O(6), and two equivalent O(9) atoms. In the third Co site, Co(3) is bonded to one O(2), one O(3), one O(5), and two equivalent O(7) atoms to form CoO5 trigonal bipyramids that share corners with two equivalent Co(1)O5 trigonal bipyramids, corners with two equivalent Co(3)O5 trigonal bipyramids, edges with two equivalent Y(1)O7 pentagonal bipyramids, and edges with two equivalent Y(2)O7 pentagonal bipyramids. In the fourth Co site, Co(4) is bonded in a distorted T-shaped geometry to one O(1), one O(4), and one O(6) atom. There are nine inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ba(1), two equivalent Ba(2), one Co(1), and one Co(4) atom to form distorted OBa4Co2 octahedra that share corners with two equivalent O(3)Ba2Y2Co2 octahedra, corners with four equivalent O(2)Ba4Co2 octahedra, edges with two equivalent O(1)Ba4Co2 octahedra, edges with two equivalent O(2)Ba4Co2 octahedra, and  a faceface with one O(3)Ba2Y2Co2 octahedra. The corner-sharing octahedral tilt angles range from 3-59°. In the second O site, O(2) is bonded to two equivalent Ba(1), two equivalent Ba(2), one Co(2), and one Co(3) atom to form distorted OBa4Co2 octahedra that share corners with two equivalent O(3)Ba2Y2Co2 octahedra, corners with four equivalent O(1)Ba4Co2 octahedra, edges with two equivalent O(1)Ba4Co2 octahedra, edges with two equivalent O(2)Ba4Co2 octahedra, and  a faceface with one O(3)Ba2Y2Co2 octahedra. The corner-sharing octahedral tilt angles range from 3-65°. In the third O site, O(3) is bonded to two equivalent Ba(2), two equivalent Y(1), one Co(1), and one Co(3) atom to form distorted OBa2Y2Co2 octahedra that share corners with two equivalent O(1)Ba4Co2 octahedra, corners with two equivalent O(2)Ba4Co2 octahedra, edges with two equivalent O(3)Ba2Y2Co2 octahedra,  a faceface with one O(1)Ba4Co2 octahedra, and  a faceface with one O(2)Ba4Co2 octahedra. The corner-sharing octahedral tilt angles range from 59-65°. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to two equivalent Ba(2), two equivalent Y(2), one Co(2), and one Co(4) atom. In the fifth O site, O(5) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Y(2), one Co(1), and one Co(3) atom. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Y(1), one Co(2), and one Co(4) atom. In the seventh O site, O(7) is bonded in a distorted see-saw-like geometry to one Y(1), one Y(2), and two equivalent Co(3) atoms. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one Ba(1), one Ba(2), one Y(1), one Y(2), and two equivalent Co(1) atoms. In the ninth O site, O(9) is bonded in a 4-coordinate geometry to one Ba(1), one Ba(2), one Y(1), one Y(2), and two equivalent Co(2) atoms. is represented by the CIF card [CIF]
data_Ba2Y2Co4O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.742
_cell_length_b   8.302
_cell_length_c   8.795
_cell_angle_alpha   118.483
_cell_angle_beta   90.045
_cell_angle_gamma   90.005
_symmetry_Int_Tables_number   1
_cell_volume   240.169
_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
  Ba  Ba0  1  0.999  0.989  0.494  1.0
  Ba  Ba1  1  0.000  0.489  0.482  1.0
  Y  Y2  1  0.001  0.236  0.008  1.0
  Y  Y3  1  1.000  0.773  0.010  1.0
  Co  Co4  1  0.500  0.122  0.253  1.0
  Co  Co5  1  0.500  0.858  0.741  1.0
  Co  Co6  1  0.500  0.603  0.211  1.0
  Co  Co7  1  0.500  0.382  0.759  1.0
  O  O8  1  0.500  0.260  0.512  1.0
  O  O9  1  0.500  0.745  0.487  1.0
  O  O10  1  0.500  0.352  0.198  1.0
  O  O11  1  0.500  0.632  0.813  1.0
  O  O12  1  0.500  0.852  0.197  1.0
  O  O13  1  0.501  0.194  0.817  1.0
  O  O14  1  0.000  0.548  0.090  1.0
  O  O15  1  1.000  0.090  0.173  1.0
  O  O16  1  0.000  0.911  0.819  1.0
[/CIF]
.