The material described by Ba3MgNb2CoO9 crystallizes in the triclinic P1 space group. There are three inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to one O(1), one O(3), one O(4), one O(6), one O(7), one O(9), two equivalent O(2), two equivalent O(5), and two equivalent O(8) atoms to form BaO12 cuboctahedra that share corners with three equivalent Ba(3)O12 cuboctahedra, corners with six equivalent Ba(1)O12 cuboctahedra, edges with three equivalent Co(1)BaMgO3 trigonal bipyramids, faces with three equivalent Ba(3)O12 cuboctahedra, faces with two equivalent Nb(2)O6 octahedra, and faces with three equivalent Nb(1)O6 octahedra. In the second Ba site, Ba(2) is bonded in a 10-coordinate geometry to one Co(1), one O(3), one O(6), one O(7), two equivalent O(1), two equivalent O(4), and two equivalent O(9) atoms. In the third Ba site, Ba(3) is bonded to one O(1), one O(2), one O(4), one O(5), one O(8), one O(9), two equivalent O(3), two equivalent O(6), and two equivalent O(7) atoms to form BaO12 cuboctahedra that share corners with three equivalent Ba(1)O12 cuboctahedra, corners with six equivalent Ba(3)O12 cuboctahedra, corners with three equivalent Co(1)BaMgO3 trigonal bipyramids, faces with three equivalent Ba(1)O12 cuboctahedra, faces with two equivalent Nb(1)O6 octahedra, and faces with three equivalent Nb(2)O6 octahedra. Mg(1) is bonded in a 3-coordinate geometry to one Co(1), one O(3), one O(6), and one O(7) atom. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(1), one O(2), one O(4), one O(5), one O(8), and one O(9) atom to form NbO6 octahedra that share corners with three equivalent Nb(2)O6 octahedra, corners with three equivalent Co(1)BaMgO3 trigonal bipyramids, faces with two equivalent Ba(3)O12 cuboctahedra, and faces with three equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-2°. In the second Nb site, Nb(2) is bonded to one O(1), one O(3), one O(4), one O(6), one O(7), and one O(9) atom to form NbO6 octahedra that share corners with three equivalent Nb(1)O6 octahedra, faces with two equivalent Ba(1)O12 cuboctahedra, and faces with three equivalent Ba(3)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-2°. Co(1) is bonded to one Ba(2), one Mg(1), one O(2), one O(5), and one O(8) atom to form distorted CoBaMgO3 trigonal bipyramids that share corners with three equivalent Ba(3)O12 cuboctahedra, corners with three equivalent Nb(1)O6 octahedra, and edges with three equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 42-44°. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a distorted linear geometry to one Ba(1), one Ba(3), two equivalent Ba(2), one Nb(1), and one Nb(2) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Ba(3), two equivalent Ba(1), one Nb(1), and one Co(1) atom. In the third O site, O(3) is bonded in a 2-coordinate geometry to one Ba(1), one Ba(2), two equivalent Ba(3), one Mg(1), and one Nb(2) atom. In the fourth O site, O(4) is bonded in a distorted linear geometry to one Ba(1), one Ba(3), two equivalent Ba(2), one Nb(1), and one Nb(2) atom. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to one Ba(3), two equivalent Ba(1), one Nb(1), and one Co(1) atom. In the sixth O site, O(6) is bonded in a 2-coordinate geometry to one Ba(1), one Ba(2), two equivalent Ba(3), one Mg(1), and one Nb(2) atom. In the seventh O site, O(7) is bonded in a 2-coordinate geometry to one Ba(1), one Ba(2), two equivalent Ba(3), one Mg(1), and one Nb(2) atom. In the eighth O site, O(8) is bonded in a 2-coordinate geometry to one Ba(3), two equivalent Ba(1), one Nb(1), and one Co(1) atom. In the ninth O site, O(9) is bonded in a distorted linear geometry to one Ba(1), one Ba(3), two equivalent Ba(2), one Nb(1), and one Nb(2) atom. is represented by the CIF file [CIF]
data_Ba3MgNb2CoO9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.937
_cell_length_b   5.944
_cell_length_c   7.839
_cell_angle_alpha   90.479
_cell_angle_beta   89.806
_cell_angle_gamma   119.919
_symmetry_Int_Tables_number   1
_cell_volume   239.741
_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  0.667  0.334  0.368  1.0
  Ba  Ba1  1  0.000  0.999  0.988  1.0
  Ba  Ba2  1  0.333  0.663  0.666  1.0
  Mg  Mg3  1  0.999  0.994  0.613  1.0
  Nb  Nb4  1  0.334  0.668  0.175  1.0
  Nb  Nb5  1  0.667  0.331  0.868  1.0
  Co  Co6  1  0.000  0.003  0.325  1.0
  O  O7  1  0.501  0.501  0.022  1.0
  O  O8  1  0.182  0.365  0.339  1.0
  O  O9  1  0.825  0.647  0.713  1.0
  O  O10  1  1.000  0.501  0.023  1.0
  O  O11  1  0.180  0.821  0.342  1.0
  O  O12  1  0.347  0.170  0.715  1.0
  O  O13  1  0.826  0.169  0.716  1.0
  O  O14  1  0.638  0.820  0.342  1.0
  O  O15  1  0.501  0.003  0.025  1.0
[/CIF]
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The material described by Ba3MgNb2CoO9 crystallizes in the triclinic P1 space group. There are three inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to one O(1), one O(3), one O(4), one O(6), one O(7), one O(9), two equivalent O(2), two equivalent O(5), and two equivalent O(8) atoms to form BaO12 cuboctahedra that share corners with three equivalent Ba(3)O12 cuboctahedra, corners with six equivalent Ba(1)O12 cuboctahedra, edges with three equivalent Co(1)BaMgO3 trigonal bipyramids, faces with three equivalent Ba(3)O12 cuboctahedra, faces with two equivalent Nb(2)O6 octahedra, and faces with three equivalent Nb(1)O6 octahedra. In the second Ba site, Ba(2) is bonded in a 10-coordinate geometry to one Co(1), one O(3), one O(6), one O(7), two equivalent O(1), two equivalent O(4), and two equivalent O(9) atoms. In the third Ba site, Ba(3) is bonded to one O(1), one O(2), one O(4), one O(5), one O(8), one O(9), two equivalent O(3), two equivalent O(6), and two equivalent O(7) atoms to form BaO12 cuboctahedra that share corners with three equivalent Ba(1)O12 cuboctahedra, corners with six equivalent Ba(3)O12 cuboctahedra, corners with three equivalent Co(1)BaMgO3 trigonal bipyramids, faces with three equivalent Ba(1)O12 cuboctahedra, faces with two equivalent Nb(1)O6 octahedra, and faces with three equivalent Nb(2)O6 octahedra. Mg(1) is bonded in a 3-coordinate geometry to one Co(1), one O(3), one O(6), and one O(7) atom. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(1), one O(2), one O(4), one O(5), one O(8), and one O(9) atom to form NbO6 octahedra that share corners with three equivalent Nb(2)O6 octahedra, corners with three equivalent Co(1)BaMgO3 trigonal bipyramids, faces with two equivalent Ba(3)O12 cuboctahedra, and faces with three equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-2°. In the second Nb site, Nb(2) is bonded to one O(1), one O(3), one O(4), one O(6), one O(7), and one O(9) atom to form NbO6 octahedra that share corners with three equivalent Nb(1)O6 octahedra, faces with two equivalent Ba(1)O12 cuboctahedra, and faces with three equivalent Ba(3)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-2°. Co(1) is bonded to one Ba(2), one Mg(1), one O(2), one O(5), and one O(8) atom to form distorted CoBaMgO3 trigonal bipyramids that share corners with three equivalent Ba(3)O12 cuboctahedra, corners with three equivalent Nb(1)O6 octahedra, and edges with three equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 42-44°. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a distorted linear geometry to one Ba(1), one Ba(3), two equivalent Ba(2), one Nb(1), and one Nb(2) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Ba(3), two equivalent Ba(1), one Nb(1), and one Co(1) atom. In the third O site, O(3) is bonded in a 2-coordinate geometry to one Ba(1), one Ba(2), two equivalent Ba(3), one Mg(1), and one Nb(2) atom. In the fourth O site, O(4) is bonded in a distorted linear geometry to one Ba(1), one Ba(3), two equivalent Ba(2), one Nb(1), and one Nb(2) atom. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to one Ba(3), two equivalent Ba(1), one Nb(1), and one Co(1) atom. In the sixth O site, O(6) is bonded in a 2-coordinate geometry to one Ba(1), one Ba(2), two equivalent Ba(3), one Mg(1), and one Nb(2) atom. In the seventh O site, O(7) is bonded in a 2-coordinate geometry to one Ba(1), one Ba(2), two equivalent Ba(3), one Mg(1), and one Nb(2) atom. In the eighth O site, O(8) is bonded in a 2-coordinate geometry to one Ba(3), two equivalent Ba(1), one Nb(1), and one Co(1) atom. In the ninth O site, O(9) is bonded in a distorted linear geometry to one Ba(1), one Ba(3), two equivalent Ba(2), one Nb(1), and one Nb(2) atom. is represented by the CIF file [CIF]
data_Ba3MgNb2CoO9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.937
_cell_length_b   5.944
_cell_length_c   7.839
_cell_angle_alpha   90.479
_cell_angle_beta   89.806
_cell_angle_gamma   119.919
_symmetry_Int_Tables_number   1
_cell_volume   239.741
_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  0.667  0.334  0.368  1.0
  Ba  Ba1  1  0.000  0.999  0.988  1.0
  Ba  Ba2  1  0.333  0.663  0.666  1.0
  Mg  Mg3  1  0.999  0.994  0.613  1.0
  Nb  Nb4  1  0.334  0.668  0.175  1.0
  Nb  Nb5  1  0.667  0.331  0.868  1.0
  Co  Co6  1  0.000  0.003  0.325  1.0
  O  O7  1  0.501  0.501  0.022  1.0
  O  O8  1  0.182  0.365  0.339  1.0
  O  O9  1  0.825  0.647  0.713  1.0
  O  O10  1  1.000  0.501  0.023  1.0
  O  O11  1  0.180  0.821  0.342  1.0
  O  O12  1  0.347  0.170  0.715  1.0
  O  O13  1  0.826  0.169  0.716  1.0
  O  O14  1  0.638  0.820  0.342  1.0
  O  O15  1  0.501  0.003  0.025  1.0
[/CIF]
.