The structure described by Ba2MgCeNbO6 is (La,Ba)CuO4-derived structured and crystallizes in the monoclinic Cm space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 9-coordinate geometry to one O(1), two equivalent O(2), two equivalent O(3), and four equivalent O(4) atoms. In the second Ba site, Ba(2) is bonded in a 9-coordinate geometry to one O(2), two equivalent O(1), two equivalent O(4), and four equivalent O(3) atoms. Mg(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms. Ce(1) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms to form distorted CeO6 pentagonal pyramids that share corners with three equivalent Nb(1)O6 octahedra and  a faceface with one Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-8°. Nb(1) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms to form NbO6 octahedra that share corners with three equivalent Ce(1)O6 pentagonal pyramids and  a faceface with one Ce(1)O6 pentagonal pyramid. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Ba(1), two equivalent Ba(2), one Mg(1), one Ce(1), and one Nb(1) atom to form a mixture of distorted edge, face, and corner-sharing OBa3CeMgNb octahedra. The corner-sharing octahedral tilt angles range from 5-63°. In the second O site, O(2) is bonded to one Ba(2), two equivalent Ba(1), one Mg(1), one Ce(1), and one Nb(1) atom to form a mixture of distorted edge, face, and corner-sharing OBa3CeMgNb octahedra. The corner-sharing octahedral tilt angles range from 5-62°. In the third O site, O(3) is bonded to one Ba(1), two equivalent Ba(2), one Mg(1), one Ce(1), and one Nb(1) atom to form a mixture of distorted edge, face, and corner-sharing OBa3CeMgNb octahedra. The corner-sharing octahedral tilt angles range from 2-63°. In the fourth O site, O(4) is bonded to one Ba(2), two equivalent Ba(1), one Mg(1), one Ce(1), and one Nb(1) atom to form a mixture of distorted edge, face, and corner-sharing OBa3CeMgNb octahedra. The corner-sharing octahedral tilt angles range from 2-63°. is represented by the CIF card [CIF]
data_Ba2CeMgNbO6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.009
_cell_length_b   6.597
_cell_length_c   5.963
_cell_angle_alpha   87.334
_cell_angle_beta   59.745
_cell_angle_gamma   62.905
_symmetry_Int_Tables_number   1
_cell_volume   176.550
_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  0.720  0.647  0.914  1.0
  Ba  Ba1  1  0.241  0.359  0.160  1.0
  Ce  Ce2  1  0.133  0.022  0.711  1.0
  Mg  Mg3  1  0.861  0.943  0.335  1.0
  Nb  Nb4  1  0.487  0.494  0.532  1.0
  O  O5  1  0.798  0.250  0.156  1.0
  O  O6  1  0.171  0.721  0.936  1.0
  O  O7  1  0.310  0.277  0.627  1.0
  O  O8  1  0.167  0.734  0.438  1.0
  O  O9  1  0.662  0.734  0.439  1.0
  O  O10  1  0.784  0.277  0.628  1.0
[/CIF]
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The structure described by Ba2MgCeNbO6 is (La,Ba)CuO4-derived structured and crystallizes in the monoclinic Cm space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 9-coordinate geometry to one O(1), two equivalent O(2), two equivalent O(3), and four equivalent O(4) atoms. In the second Ba site, Ba(2) is bonded in a 9-coordinate geometry to one O(2), two equivalent O(1), two equivalent O(4), and four equivalent O(3) atoms. Mg(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms. Ce(1) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms to form distorted CeO6 pentagonal pyramids that share corners with three equivalent Nb(1)O6 octahedra and  a faceface with one Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-8°. Nb(1) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms to form NbO6 octahedra that share corners with three equivalent Ce(1)O6 pentagonal pyramids and  a faceface with one Ce(1)O6 pentagonal pyramid. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Ba(1), two equivalent Ba(2), one Mg(1), one Ce(1), and one Nb(1) atom to form a mixture of distorted edge, face, and corner-sharing OBa3CeMgNb octahedra. The corner-sharing octahedral tilt angles range from 5-63°. In the second O site, O(2) is bonded to one Ba(2), two equivalent Ba(1), one Mg(1), one Ce(1), and one Nb(1) atom to form a mixture of distorted edge, face, and corner-sharing OBa3CeMgNb octahedra. The corner-sharing octahedral tilt angles range from 5-62°. In the third O site, O(3) is bonded to one Ba(1), two equivalent Ba(2), one Mg(1), one Ce(1), and one Nb(1) atom to form a mixture of distorted edge, face, and corner-sharing OBa3CeMgNb octahedra. The corner-sharing octahedral tilt angles range from 2-63°. In the fourth O site, O(4) is bonded to one Ba(2), two equivalent Ba(1), one Mg(1), one Ce(1), and one Nb(1) atom to form a mixture of distorted edge, face, and corner-sharing OBa3CeMgNb octahedra. The corner-sharing octahedral tilt angles range from 2-63°. is represented by the CIF card [CIF]
data_Ba2CeMgNbO6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.009
_cell_length_b   6.597
_cell_length_c   5.963
_cell_angle_alpha   87.334
_cell_angle_beta   59.745
_cell_angle_gamma   62.905
_symmetry_Int_Tables_number   1
_cell_volume   176.550
_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  0.720  0.647  0.914  1.0
  Ba  Ba1  1  0.241  0.359  0.160  1.0
  Ce  Ce2  1  0.133  0.022  0.711  1.0
  Mg  Mg3  1  0.861  0.943  0.335  1.0
  Nb  Nb4  1  0.487  0.494  0.532  1.0
  O  O5  1  0.798  0.250  0.156  1.0
  O  O6  1  0.171  0.721  0.936  1.0
  O  O7  1  0.310  0.277  0.627  1.0
  O  O8  1  0.167  0.734  0.438  1.0
  O  O9  1  0.662  0.734  0.439  1.0
  O  O10  1  0.784  0.277  0.628  1.0
[/CIF]
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