The compound described by MgTa2(FeO4)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a 4-coordinate geometry to one O(2), one O(5), one O(6), and one O(8) atom. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one O(1), one O(3), one O(4), one O(5), one O(6), and one O(7) atom to form TaO6 octahedra that share corners with three equivalent Ta(2)O5 trigonal bipyramids and edges with two equivalent Fe(1)O6 octahedra. In the second Ta site, Ta(2) is bonded to one O(1), one O(2), one O(4), one O(7), and one O(8) atom to form distorted TaO5 trigonal bipyramids that share corners with three equivalent Ta(1)O6 octahedra and corners with three equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-50°. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(2), one O(3), one O(4), one O(5), one O(6), and one O(8) atom to form FeO6 octahedra that share corners with three equivalent Ta(2)O5 trigonal bipyramids and edges with two equivalent Ta(1)O6 octahedra. In the second Fe site, Fe(2) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(7), and one O(8) atom. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Ta(1), one Ta(2), and one Fe(2) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Ta(2), one Fe(1), and one Fe(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Ta(1), one Fe(1), and one Fe(2) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Ta(1), one Ta(2), and one Fe(1) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Mg(1), one Ta(1), and one Fe(1) atom. In the sixth O site, O(6) is bonded in a T-shaped geometry to one Mg(1), one Ta(1), and one Fe(1) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Ta(1), one Ta(2), and one Fe(2) atom. In the eighth O site, O(8) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Ta(2), one Fe(1), and one Fe(2) atom. is represented by the CIF file [CIF]
data_MgTa2(FeO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.100
_cell_length_b   6.353
_cell_length_c   6.107
_cell_angle_alpha   86.548
_cell_angle_beta   113.934
_cell_angle_gamma   59.291
_symmetry_Int_Tables_number   1
_cell_volume   174.895
_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
  Mg  Mg0  1  0.248  0.556  0.198  1.0
  Ta  Ta1  1  0.272  0.206  0.521  1.0
  Ta  Ta2  1  0.998  0.077  0.924  1.0
  Fe  Fe3  1  0.742  0.754  0.505  1.0
  Fe  Fe4  1  0.515  0.571  0.914  1.0
  O  O5  1  0.578  0.236  0.805  1.0
  O  O6  1  0.036  0.769  0.827  1.0
  O  O7  1  0.470  0.840  0.689  1.0
  O  O8  1  0.013  0.282  0.704  1.0
  O  O9  1  0.035  0.586  0.378  1.0
  O  O10  1  0.480  0.177  0.346  1.0
  O  O11  1  0.960  0.236  0.184  1.0
  O  O12  1  0.404  0.770  0.194  1.0
[/CIF]
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The compound described by MgTa2(FeO4)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a 4-coordinate geometry to one O(2), one O(5), one O(6), and one O(8) atom. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one O(1), one O(3), one O(4), one O(5), one O(6), and one O(7) atom to form TaO6 octahedra that share corners with three equivalent Ta(2)O5 trigonal bipyramids and edges with two equivalent Fe(1)O6 octahedra. In the second Ta site, Ta(2) is bonded to one O(1), one O(2), one O(4), one O(7), and one O(8) atom to form distorted TaO5 trigonal bipyramids that share corners with three equivalent Ta(1)O6 octahedra and corners with three equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-50°. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(2), one O(3), one O(4), one O(5), one O(6), and one O(8) atom to form FeO6 octahedra that share corners with three equivalent Ta(2)O5 trigonal bipyramids and edges with two equivalent Ta(1)O6 octahedra. In the second Fe site, Fe(2) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(7), and one O(8) atom. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Ta(1), one Ta(2), and one Fe(2) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Ta(2), one Fe(1), and one Fe(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Ta(1), one Fe(1), and one Fe(2) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Ta(1), one Ta(2), and one Fe(1) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Mg(1), one Ta(1), and one Fe(1) atom. In the sixth O site, O(6) is bonded in a T-shaped geometry to one Mg(1), one Ta(1), and one Fe(1) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Ta(1), one Ta(2), and one Fe(2) atom. In the eighth O site, O(8) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Ta(2), one Fe(1), and one Fe(2) atom. is represented by the CIF file [CIF]
data_MgTa2(FeO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.100
_cell_length_b   6.353
_cell_length_c   6.107
_cell_angle_alpha   86.548
_cell_angle_beta   113.934
_cell_angle_gamma   59.291
_symmetry_Int_Tables_number   1
_cell_volume   174.895
_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
  Mg  Mg0  1  0.248  0.556  0.198  1.0
  Ta  Ta1  1  0.272  0.206  0.521  1.0
  Ta  Ta2  1  0.998  0.077  0.924  1.0
  Fe  Fe3  1  0.742  0.754  0.505  1.0
  Fe  Fe4  1  0.515  0.571  0.914  1.0
  O  O5  1  0.578  0.236  0.805  1.0
  O  O6  1  0.036  0.769  0.827  1.0
  O  O7  1  0.470  0.840  0.689  1.0
  O  O8  1  0.013  0.282  0.704  1.0
  O  O9  1  0.035  0.586  0.378  1.0
  O  O10  1  0.480  0.177  0.346  1.0
  O  O11  1  0.960  0.236  0.184  1.0
  O  O12  1  0.404  0.770  0.194  1.0
[/CIF]
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