The material described by Mn4Ta2O9 is Ilmenite-like structured and crystallizes in the trigonal P-3c1 space group. Ta(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form distorted TaO6 octahedra that share corners with three equivalent Mn(2)O6 octahedra, corners with six equivalent Mn(1)O6 octahedra, edges with three equivalent Mn(2)O6 octahedra, and  a faceface with one Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-57°. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to six equivalent O(2) atoms to form MnO6 octahedra that share corners with three equivalent Mn(2)O6 octahedra, corners with six equivalent Ta(1)O6 octahedra, edges with three equivalent Mn(1)O6 octahedra, and  a faceface with one Mn(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-57°. In the second Mn site, Mn(2) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form distorted MnO6 octahedra that share corners with three equivalent Ta(1)O6 octahedra, corners with three equivalent Mn(1)O6 octahedra, corners with three equivalent Mn(2)O6 octahedra, edges with three equivalent Ta(1)O6 octahedra, and  a faceface with one Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 49-69°. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ta(1) and two equivalent Mn(2) atoms to form distorted OTa2Mn2 trigonal pyramids that share corners with four equivalent O(1)Ta2Mn2 trigonal pyramids, corners with eight equivalent O(2)TaMn3 trigonal pyramids, edges with two equivalent O(1)Ta2Mn2 trigonal pyramids, and edges with two equivalent O(2)TaMn3 trigonal pyramids. In the second O site, O(2) is bonded to one Ta(1), one Mn(2), and two equivalent Mn(1) atoms to form distorted OTaMn3 trigonal pyramids that share corners with four equivalent O(1)Ta2Mn2 trigonal pyramids, corners with eight equivalent O(2)TaMn3 trigonal pyramids,  an edgeedge with one O(1)Ta2Mn2 trigonal pyramid, and edges with three equivalent O(2)TaMn3 trigonal pyramids. is represented by the CIF file [CIF]
data_Ta2Mn4O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.294
_cell_length_b   5.294
_cell_length_c   14.345
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   348.181
_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
  Ta  Ta0  1  0.000  0.000  0.357  1.0
  Ta  Ta1  1  0.000  0.000  0.143  1.0
  Ta  Ta2  1  1.000  1.000  0.643  1.0
  Ta  Ta3  1  1.000  1.000  0.857  1.0
  Mn  Mn4  1  0.667  0.333  0.483  1.0
  Mn  Mn5  1  0.667  0.333  0.983  1.0
  Mn  Mn6  1  0.667  0.333  0.696  1.0
  Mn  Mn7  1  0.667  0.333  0.196  1.0
  Mn  Mn8  1  0.333  0.667  0.017  1.0
  Mn  Mn9  1  0.333  0.667  0.517  1.0
  Mn  Mn10  1  0.333  0.667  0.804  1.0
  Mn  Mn11  1  0.333  0.667  0.304  1.0
  O  O12  1  0.279  0.000  0.250  1.0
  O  O13  1  0.000  0.279  0.250  1.0
  O  O14  1  0.721  0.721  0.250  1.0
  O  O15  1  0.721  1.000  0.750  1.0
  O  O16  1  1.000  0.721  0.750  1.0
  O  O17  1  0.279  0.279  0.750  1.0
  O  O18  1  0.689  0.662  0.586  1.0
  O  O19  1  0.338  0.026  0.586  1.0
  O  O20  1  0.974  0.311  0.586  1.0
  O  O21  1  0.026  0.338  0.914  1.0
  O  O22  1  0.311  0.974  0.914  1.0
  O  O23  1  0.662  0.689  0.914  1.0
  O  O24  1  0.311  0.338  0.414  1.0
  O  O25  1  0.662  0.974  0.414  1.0
  O  O26  1  0.026  0.689  0.414  1.0
  O  O27  1  0.974  0.662  0.086  1.0
  O  O28  1  0.689  0.026  0.086  1.0
  O  O29  1  0.338  0.311  0.086  1.0
[/CIF]
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The material described by Mn4Ta2O9 is Ilmenite-like structured and crystallizes in the trigonal P-3c1 space group. Ta(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form distorted TaO6 octahedra that share corners with three equivalent Mn(2)O6 octahedra, corners with six equivalent Mn(1)O6 octahedra, edges with three equivalent Mn(2)O6 octahedra, and  a faceface with one Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-57°. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to six equivalent O(2) atoms to form MnO6 octahedra that share corners with three equivalent Mn(2)O6 octahedra, corners with six equivalent Ta(1)O6 octahedra, edges with three equivalent Mn(1)O6 octahedra, and  a faceface with one Mn(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-57°. In the second Mn site, Mn(2) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form distorted MnO6 octahedra that share corners with three equivalent Ta(1)O6 octahedra, corners with three equivalent Mn(1)O6 octahedra, corners with three equivalent Mn(2)O6 octahedra, edges with three equivalent Ta(1)O6 octahedra, and  a faceface with one Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 49-69°. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ta(1) and two equivalent Mn(2) atoms to form distorted OTa2Mn2 trigonal pyramids that share corners with four equivalent O(1)Ta2Mn2 trigonal pyramids, corners with eight equivalent O(2)TaMn3 trigonal pyramids, edges with two equivalent O(1)Ta2Mn2 trigonal pyramids, and edges with two equivalent O(2)TaMn3 trigonal pyramids. In the second O site, O(2) is bonded to one Ta(1), one Mn(2), and two equivalent Mn(1) atoms to form distorted OTaMn3 trigonal pyramids that share corners with four equivalent O(1)Ta2Mn2 trigonal pyramids, corners with eight equivalent O(2)TaMn3 trigonal pyramids,  an edgeedge with one O(1)Ta2Mn2 trigonal pyramid, and edges with three equivalent O(2)TaMn3 trigonal pyramids. is represented by the CIF file [CIF]
data_Ta2Mn4O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.294
_cell_length_b   5.294
_cell_length_c   14.345
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   348.181
_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
  Ta  Ta0  1  0.000  0.000  0.357  1.0
  Ta  Ta1  1  0.000  0.000  0.143  1.0
  Ta  Ta2  1  1.000  1.000  0.643  1.0
  Ta  Ta3  1  1.000  1.000  0.857  1.0
  Mn  Mn4  1  0.667  0.333  0.483  1.0
  Mn  Mn5  1  0.667  0.333  0.983  1.0
  Mn  Mn6  1  0.667  0.333  0.696  1.0
  Mn  Mn7  1  0.667  0.333  0.196  1.0
  Mn  Mn8  1  0.333  0.667  0.017  1.0
  Mn  Mn9  1  0.333  0.667  0.517  1.0
  Mn  Mn10  1  0.333  0.667  0.804  1.0
  Mn  Mn11  1  0.333  0.667  0.304  1.0
  O  O12  1  0.279  0.000  0.250  1.0
  O  O13  1  0.000  0.279  0.250  1.0
  O  O14  1  0.721  0.721  0.250  1.0
  O  O15  1  0.721  1.000  0.750  1.0
  O  O16  1  1.000  0.721  0.750  1.0
  O  O17  1  0.279  0.279  0.750  1.0
  O  O18  1  0.689  0.662  0.586  1.0
  O  O19  1  0.338  0.026  0.586  1.0
  O  O20  1  0.974  0.311  0.586  1.0
  O  O21  1  0.026  0.338  0.914  1.0
  O  O22  1  0.311  0.974  0.914  1.0
  O  O23  1  0.662  0.689  0.914  1.0
  O  O24  1  0.311  0.338  0.414  1.0
  O  O25  1  0.662  0.974  0.414  1.0
  O  O26  1  0.026  0.689  0.414  1.0
  O  O27  1  0.974  0.662  0.086  1.0
  O  O28  1  0.689  0.026  0.086  1.0
  O  O29  1  0.338  0.311  0.086  1.0
[/CIF]
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