The material structure described by Ca2Nb2MnO8 crystallizes in the monoclinic C2/c space group. Ca(1) is bonded in a 8-coordinate geometry to one O(1), three equivalent O(4), and four equivalent O(3) atoms. Nb(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms to form distorted NbO6 octahedra that share corners with four equivalent Mn(1)O6 octahedra and edges with two equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-54°. Mn(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form MnO6 octahedra that share corners with eight equivalent Nb(1)O6 octahedra and edges with two equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-54°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Ca(1), two equivalent Nb(1), and one Mn(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Nb(1) and two equivalent Mn(1) atoms. In the third O site, O(3) is bonded in a 6-coordinate geometry to four equivalent Ca(1) and two equivalent Nb(1) atoms. In the fourth O site, O(4) is bonded to three equivalent Ca(1) and one Nb(1) atom to form a mixture of distorted corner and edge-sharing OCa3Nb trigonal pyramids. is represented by the CIF file [CIF]
data_Ca2MnNb2O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.197
_cell_length_b   10.197
_cell_length_c   5.537
_cell_angle_alpha   88.183
_cell_angle_beta   88.183
_cell_angle_gamma   36.354
_symmetry_Int_Tables_number   1
_cell_volume   341.088
_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
  Ca  Ca0  1  0.890  0.523  0.757  1.0
  Ca  Ca1  1  0.477  0.110  0.743  1.0
  Ca  Ca2  1  0.110  0.477  0.243  1.0
  Ca  Ca3  1  0.523  0.890  0.257  1.0
  Mn  Mn4  1  0.652  0.348  0.750  1.0
  Mn  Mn5  1  0.348  0.652  0.250  1.0
  Nb  Nb6  1  0.038  0.734  0.754  1.0
  Nb  Nb7  1  0.266  0.962  0.746  1.0
  Nb  Nb8  1  0.962  0.266  0.246  1.0
  Nb  Nb9  1  0.734  0.038  0.254  1.0
  O  O10  1  0.050  0.805  0.084  1.0
  O  O11  1  0.195  0.950  0.416  1.0
  O  O12  1  0.950  0.195  0.916  1.0
  O  O13  1  0.805  0.050  0.584  1.0
  O  O14  1  0.291  0.592  0.590  1.0
  O  O15  1  0.408  0.709  0.910  1.0
  O  O16  1  0.709  0.408  0.410  1.0
  O  O17  1  0.592  0.291  0.090  1.0
  O  O18  1  0.877  0.756  0.503  1.0
  O  O19  1  0.244  0.123  0.997  1.0
  O  O20  1  0.461  0.171  0.345  1.0
  O  O21  1  0.829  0.539  0.155  1.0
  O  O22  1  0.539  0.829  0.655  1.0
  O  O23  1  0.171  0.461  0.845  1.0
  O  O24  1  0.756  0.877  0.003  1.0
  O  O25  1  0.123  0.244  0.497  1.0
[/CIF]
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The material structure described by Ca2Nb2MnO8 crystallizes in the monoclinic C2/c space group. Ca(1) is bonded in a 8-coordinate geometry to one O(1), three equivalent O(4), and four equivalent O(3) atoms. Nb(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms to form distorted NbO6 octahedra that share corners with four equivalent Mn(1)O6 octahedra and edges with two equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-54°. Mn(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form MnO6 octahedra that share corners with eight equivalent Nb(1)O6 octahedra and edges with two equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-54°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Ca(1), two equivalent Nb(1), and one Mn(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Nb(1) and two equivalent Mn(1) atoms. In the third O site, O(3) is bonded in a 6-coordinate geometry to four equivalent Ca(1) and two equivalent Nb(1) atoms. In the fourth O site, O(4) is bonded to three equivalent Ca(1) and one Nb(1) atom to form a mixture of distorted corner and edge-sharing OCa3Nb trigonal pyramids. is represented by the CIF file [CIF]
data_Ca2MnNb2O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.197
_cell_length_b   10.197
_cell_length_c   5.537
_cell_angle_alpha   88.183
_cell_angle_beta   88.183
_cell_angle_gamma   36.354
_symmetry_Int_Tables_number   1
_cell_volume   341.088
_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
  Ca  Ca0  1  0.890  0.523  0.757  1.0
  Ca  Ca1  1  0.477  0.110  0.743  1.0
  Ca  Ca2  1  0.110  0.477  0.243  1.0
  Ca  Ca3  1  0.523  0.890  0.257  1.0
  Mn  Mn4  1  0.652  0.348  0.750  1.0
  Mn  Mn5  1  0.348  0.652  0.250  1.0
  Nb  Nb6  1  0.038  0.734  0.754  1.0
  Nb  Nb7  1  0.266  0.962  0.746  1.0
  Nb  Nb8  1  0.962  0.266  0.246  1.0
  Nb  Nb9  1  0.734  0.038  0.254  1.0
  O  O10  1  0.050  0.805  0.084  1.0
  O  O11  1  0.195  0.950  0.416  1.0
  O  O12  1  0.950  0.195  0.916  1.0
  O  O13  1  0.805  0.050  0.584  1.0
  O  O14  1  0.291  0.592  0.590  1.0
  O  O15  1  0.408  0.709  0.910  1.0
  O  O16  1  0.709  0.408  0.410  1.0
  O  O17  1  0.592  0.291  0.090  1.0
  O  O18  1  0.877  0.756  0.503  1.0
  O  O19  1  0.244  0.123  0.997  1.0
  O  O20  1  0.461  0.171  0.345  1.0
  O  O21  1  0.829  0.539  0.155  1.0
  O  O22  1  0.539  0.829  0.655  1.0
  O  O23  1  0.171  0.461  0.845  1.0
  O  O24  1  0.756  0.877  0.003  1.0
  O  O25  1  0.123  0.244  0.497  1.0
[/CIF]
.