The material described by Ta2Mn3O8 crystallizes in the tetragonal I4_1/a space group. Ta(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms to form TaO6 octahedra that share corners with two equivalent Ta(1)O6 octahedra, corners with two equivalent Mn(1)O4 tetrahedra, and  an edgeedge with one Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles are 29°. There are three inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to four equivalent O(3) atoms to form MnO4 tetrahedra that share corners with eight equivalent Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles are 62°. In the second Mn site, Mn(2) is bonded in a 8-coordinate geometry to four equivalent O(2) and four equivalent O(4) atoms. In the third Mn site, Mn(3) is bonded in a 6-coordinate geometry to one O(1), one O(3), two equivalent O(2), and two equivalent O(4) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to two equivalent Ta(1) and one Mn(3) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Ta(1), one Mn(2), and two equivalent Mn(3) atoms. In the third O site, O(3) is bonded to two equivalent Ta(1), one Mn(1), and one Mn(3) atom to form distorted OTa2Mn2 tetrahedra that share corners with three equivalent O(3)Ta2Mn2 tetrahedra, corners with four equivalent O(4)TaMn3 tetrahedra, and  an edgeedge with one O(3)Ta2Mn2 tetrahedra. In the fourth O site, O(4) is bonded to one Ta(1), one Mn(2), and two equivalent Mn(3) atoms to form distorted OTaMn3 tetrahedra that share corners with three equivalent O(4)TaMn3 tetrahedra, corners with four equivalent O(3)Ta2Mn2 tetrahedra, and  an edgeedge with one O(4)TaMn3 tetrahedra. is represented by the CIF card [CIF]
data_Ta2Mn3O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.479
_cell_length_b   9.479
_cell_length_c   9.479
_cell_angle_alpha   105.980
_cell_angle_beta   105.980
_cell_angle_gamma   116.704
_symmetry_Int_Tables_number   1
_cell_volume   647.780
_cell_formula_units_Z   4
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  0.809  0.428  0.228  1.0
  Ta  Ta1  1  0.678  0.950  0.120  1.0
  Ta  Ta2  1  0.831  0.559  0.880  1.0
  Ta  Ta3  1  0.200  0.581  0.772  1.0
  Ta  Ta4  1  0.441  0.322  0.272  1.0
  Ta  Ta5  1  0.572  0.800  0.380  1.0
  Ta  Ta6  1  0.419  0.191  0.620  1.0
  Ta  Ta7  1  0.050  0.169  0.728  1.0
  Mn  Mn8  1  0.500  0.500  0.000  1.0
  Mn  Mn9  1  0.750  0.250  0.500  1.0
  Mn  Mn10  1  0.000  0.000  0.000  1.0
  Mn  Mn11  1  0.250  0.750  0.500  1.0
  Mn  Mn12  1  0.265  0.857  0.183  1.0
  Mn  Mn13  1  0.107  0.424  0.092  1.0
  Mn  Mn14  1  0.333  0.015  0.908  1.0
  Mn  Mn15  1  0.674  0.083  0.817  1.0
  Mn  Mn16  1  0.985  0.893  0.317  1.0
  Mn  Mn17  1  0.143  0.326  0.408  1.0
  Mn  Mn18  1  0.917  0.735  0.592  1.0
  Mn  Mn19  1  0.576  0.667  0.683  1.0
  O  O20  1  0.829  0.446  0.034  1.0
  O  O21  1  0.696  0.162  0.117  1.0
  O  O22  1  0.045  0.579  0.883  1.0
  O  O23  1  0.412  0.795  0.966  1.0
  O  O24  1  0.421  0.304  0.466  1.0
  O  O25  1  0.554  0.588  0.383  1.0
  O  O26  1  0.205  0.171  0.617  1.0
  O  O27  1  0.838  0.955  0.534  1.0
  O  O28  1  0.933  0.067  0.259  1.0
  O  O29  1  0.317  0.558  0.634  1.0
  O  O30  1  0.924  0.683  0.366  1.0
  O  O31  1  0.808  0.674  0.741  1.0
  O  O32  1  0.317  0.683  0.241  1.0
  O  O33  1  0.933  0.192  0.866  1.0
  O  O34  1  0.326  0.067  0.134  1.0
  O  O35  1  0.442  0.076  0.759  1.0
  O  O36  1  0.541  0.355  0.109  1.0
  O  O37  1  0.605  0.996  0.315  1.0
  O  O38  1  0.682  0.291  0.685  1.0
  O  O39  1  0.246  0.432  0.891  1.0
  O  O40  1  0.105  0.028  0.819  1.0
  O  O41  1  0.278  0.960  0.423  1.0
  O  O42  1  0.537  0.855  0.577  1.0
  O  O43  1  0.210  0.287  0.181  1.0
  O  O44  1  0.145  0.722  0.681  1.0
  O  O45  1  0.972  0.790  0.077  1.0
  O  O46  1  0.713  0.895  0.923  1.0
  O  O47  1  0.040  0.463  0.319  1.0
  O  O48  1  0.004  0.318  0.609  1.0
  O  O49  1  0.568  0.459  0.815  1.0
  O  O50  1  0.645  0.754  0.185  1.0
  O  O51  1  0.709  0.395  0.391  1.0
[/CIF]
.
The material described by Ta2Mn3O8 crystallizes in the tetragonal I4_1/a space group. Ta(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms to form TaO6 octahedra that share corners with two equivalent Ta(1)O6 octahedra, corners with two equivalent Mn(1)O4 tetrahedra, and  an edgeedge with one Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles are 29°. There are three inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to four equivalent O(3) atoms to form MnO4 tetrahedra that share corners with eight equivalent Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles are 62°. In the second Mn site, Mn(2) is bonded in a 8-coordinate geometry to four equivalent O(2) and four equivalent O(4) atoms. In the third Mn site, Mn(3) is bonded in a 6-coordinate geometry to one O(1), one O(3), two equivalent O(2), and two equivalent O(4) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to two equivalent Ta(1) and one Mn(3) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Ta(1), one Mn(2), and two equivalent Mn(3) atoms. In the third O site, O(3) is bonded to two equivalent Ta(1), one Mn(1), and one Mn(3) atom to form distorted OTa2Mn2 tetrahedra that share corners with three equivalent O(3)Ta2Mn2 tetrahedra, corners with four equivalent O(4)TaMn3 tetrahedra, and  an edgeedge with one O(3)Ta2Mn2 tetrahedra. In the fourth O site, O(4) is bonded to one Ta(1), one Mn(2), and two equivalent Mn(3) atoms to form distorted OTaMn3 tetrahedra that share corners with three equivalent O(4)TaMn3 tetrahedra, corners with four equivalent O(3)Ta2Mn2 tetrahedra, and  an edgeedge with one O(4)TaMn3 tetrahedra. is represented by the CIF card [CIF]
data_Ta2Mn3O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.479
_cell_length_b   9.479
_cell_length_c   9.479
_cell_angle_alpha   105.980
_cell_angle_beta   105.980
_cell_angle_gamma   116.704
_symmetry_Int_Tables_number   1
_cell_volume   647.780
_cell_formula_units_Z   4
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  0.809  0.428  0.228  1.0
  Ta  Ta1  1  0.678  0.950  0.120  1.0
  Ta  Ta2  1  0.831  0.559  0.880  1.0
  Ta  Ta3  1  0.200  0.581  0.772  1.0
  Ta  Ta4  1  0.441  0.322  0.272  1.0
  Ta  Ta5  1  0.572  0.800  0.380  1.0
  Ta  Ta6  1  0.419  0.191  0.620  1.0
  Ta  Ta7  1  0.050  0.169  0.728  1.0
  Mn  Mn8  1  0.500  0.500  0.000  1.0
  Mn  Mn9  1  0.750  0.250  0.500  1.0
  Mn  Mn10  1  0.000  0.000  0.000  1.0
  Mn  Mn11  1  0.250  0.750  0.500  1.0
  Mn  Mn12  1  0.265  0.857  0.183  1.0
  Mn  Mn13  1  0.107  0.424  0.092  1.0
  Mn  Mn14  1  0.333  0.015  0.908  1.0
  Mn  Mn15  1  0.674  0.083  0.817  1.0
  Mn  Mn16  1  0.985  0.893  0.317  1.0
  Mn  Mn17  1  0.143  0.326  0.408  1.0
  Mn  Mn18  1  0.917  0.735  0.592  1.0
  Mn  Mn19  1  0.576  0.667  0.683  1.0
  O  O20  1  0.829  0.446  0.034  1.0
  O  O21  1  0.696  0.162  0.117  1.0
  O  O22  1  0.045  0.579  0.883  1.0
  O  O23  1  0.412  0.795  0.966  1.0
  O  O24  1  0.421  0.304  0.466  1.0
  O  O25  1  0.554  0.588  0.383  1.0
  O  O26  1  0.205  0.171  0.617  1.0
  O  O27  1  0.838  0.955  0.534  1.0
  O  O28  1  0.933  0.067  0.259  1.0
  O  O29  1  0.317  0.558  0.634  1.0
  O  O30  1  0.924  0.683  0.366  1.0
  O  O31  1  0.808  0.674  0.741  1.0
  O  O32  1  0.317  0.683  0.241  1.0
  O  O33  1  0.933  0.192  0.866  1.0
  O  O34  1  0.326  0.067  0.134  1.0
  O  O35  1  0.442  0.076  0.759  1.0
  O  O36  1  0.541  0.355  0.109  1.0
  O  O37  1  0.605  0.996  0.315  1.0
  O  O38  1  0.682  0.291  0.685  1.0
  O  O39  1  0.246  0.432  0.891  1.0
  O  O40  1  0.105  0.028  0.819  1.0
  O  O41  1  0.278  0.960  0.423  1.0
  O  O42  1  0.537  0.855  0.577  1.0
  O  O43  1  0.210  0.287  0.181  1.0
  O  O44  1  0.145  0.722  0.681  1.0
  O  O45  1  0.972  0.790  0.077  1.0
  O  O46  1  0.713  0.895  0.923  1.0
  O  O47  1  0.040  0.463  0.319  1.0
  O  O48  1  0.004  0.318  0.609  1.0
  O  O49  1  0.568  0.459  0.815  1.0
  O  O50  1  0.645  0.754  0.185  1.0
  O  O51  1  0.709  0.395  0.391  1.0
[/CIF]
.