The structure described by Mg2TiTa2O8 crystallizes in the monoclinic C2/c space group. Mg(1) is bonded in a 6-coordinate geometry to three equivalent O(3) and three equivalent O(4) atoms. Ti(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form TiO6 octahedra that share corners with eight equivalent Ta(1)O6 octahedra and edges with two equivalent Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-56°. Ta(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms to form distorted TaO6 octahedra that share corners with four equivalent Ti(1)O6 octahedra and edges with two equivalent Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-56°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Ti(1) and two equivalent Ta(1) atoms. In the second O site, O(2) is bonded in a distorted T-shaped geometry to two equivalent Ti(1) and one Ta(1) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to three equivalent Mg(1) and two equivalent Ta(1) atoms. In the fourth O site, O(4) is bonded to three equivalent Mg(1) and one Ta(1) atom to form a mixture of corner and edge-sharing OMg3Ta trigonal pyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg2Ta2TiO8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.037
_cell_length_b   10.037
_cell_length_c   5.231
_cell_angle_alpha   89.921
_cell_angle_beta   89.921
_cell_angle_gamma   34.803
_symmetry_Int_Tables_number   1
_cell_volume   300.759
_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
  Mg  Mg0  1  0.870  0.580  0.761  1.0
  Mg  Mg1  1  0.420  0.130  0.739  1.0
  Mg  Mg2  1  0.130  0.420  0.239  1.0
  Mg  Mg3  1  0.580  0.870  0.261  1.0
  Ta  Ta4  1  0.037  0.730  0.744  1.0
  Ta  Ta5  1  0.270  0.963  0.756  1.0
  Ta  Ta6  1  0.963  0.270  0.256  1.0
  Ta  Ta7  1  0.730  0.037  0.244  1.0
  Ti  Ti8  1  0.626  0.374  0.750  1.0
  Ti  Ti9  1  0.374  0.626  0.250  1.0
  O  O10  1  0.051  0.808  0.081  1.0
  O  O11  1  0.192  0.949  0.419  1.0
  O  O12  1  0.949  0.192  0.919  1.0
  O  O13  1  0.808  0.051  0.581  1.0
  O  O14  1  0.311  0.573  0.590  1.0
  O  O15  1  0.427  0.689  0.910  1.0
  O  O16  1  0.689  0.427  0.410  1.0
  O  O17  1  0.573  0.311  0.090  1.0
  O  O18  1  0.916  0.714  0.443  1.0
  O  O19  1  0.286  0.084  0.057  1.0
  O  O20  1  0.456  0.160  0.371  1.0
  O  O21  1  0.840  0.544  0.129  1.0
  O  O22  1  0.544  0.840  0.629  1.0
  O  O23  1  0.160  0.456  0.871  1.0
  O  O24  1  0.714  0.916  0.943  1.0
  O  O25  1  0.084  0.286  0.557  1.0
[/CIF]
.
The structure described by Mg2TiTa2O8 crystallizes in the monoclinic C2/c space group. Mg(1) is bonded in a 6-coordinate geometry to three equivalent O(3) and three equivalent O(4) atoms. Ti(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form TiO6 octahedra that share corners with eight equivalent Ta(1)O6 octahedra and edges with two equivalent Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-56°. Ta(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms to form distorted TaO6 octahedra that share corners with four equivalent Ti(1)O6 octahedra and edges with two equivalent Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-56°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Ti(1) and two equivalent Ta(1) atoms. In the second O site, O(2) is bonded in a distorted T-shaped geometry to two equivalent Ti(1) and one Ta(1) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to three equivalent Mg(1) and two equivalent Ta(1) atoms. In the fourth O site, O(4) is bonded to three equivalent Mg(1) and one Ta(1) atom to form a mixture of corner and edge-sharing OMg3Ta trigonal pyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg2Ta2TiO8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.037
_cell_length_b   10.037
_cell_length_c   5.231
_cell_angle_alpha   89.921
_cell_angle_beta   89.921
_cell_angle_gamma   34.803
_symmetry_Int_Tables_number   1
_cell_volume   300.759
_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
  Mg  Mg0  1  0.870  0.580  0.761  1.0
  Mg  Mg1  1  0.420  0.130  0.739  1.0
  Mg  Mg2  1  0.130  0.420  0.239  1.0
  Mg  Mg3  1  0.580  0.870  0.261  1.0
  Ta  Ta4  1  0.037  0.730  0.744  1.0
  Ta  Ta5  1  0.270  0.963  0.756  1.0
  Ta  Ta6  1  0.963  0.270  0.256  1.0
  Ta  Ta7  1  0.730  0.037  0.244  1.0
  Ti  Ti8  1  0.626  0.374  0.750  1.0
  Ti  Ti9  1  0.374  0.626  0.250  1.0
  O  O10  1  0.051  0.808  0.081  1.0
  O  O11  1  0.192  0.949  0.419  1.0
  O  O12  1  0.949  0.192  0.919  1.0
  O  O13  1  0.808  0.051  0.581  1.0
  O  O14  1  0.311  0.573  0.590  1.0
  O  O15  1  0.427  0.689  0.910  1.0
  O  O16  1  0.689  0.427  0.410  1.0
  O  O17  1  0.573  0.311  0.090  1.0
  O  O18  1  0.916  0.714  0.443  1.0
  O  O19  1  0.286  0.084  0.057  1.0
  O  O20  1  0.456  0.160  0.371  1.0
  O  O21  1  0.840  0.544  0.129  1.0
  O  O22  1  0.544  0.840  0.629  1.0
  O  O23  1  0.160  0.456  0.871  1.0
  O  O24  1  0.714  0.916  0.943  1.0
  O  O25  1  0.084  0.286  0.557  1.0
[/CIF]
.