The material described by Ba4MgTl8O16 crystallizes in the monoclinic Pm space group. There are four inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 8-coordinate geometry to one O(16), one O(8), two equivalent O(3), two equivalent O(4), and two equivalent O(7) atoms. In the second Ba site, Ba(2) is bonded in a 7-coordinate geometry to one O(1), two equivalent O(2), two equivalent O(5), and two equivalent O(6) atoms. In the third Ba site, Ba(3) is bonded in a 8-coordinate geometry to one O(16), one O(8), two equivalent O(11), two equivalent O(12), and two equivalent O(15) atoms. In the fourth Ba site, Ba(4) is bonded in a 8-coordinate geometry to one O(1), one O(9), two equivalent O(10), two equivalent O(13), and two equivalent O(14) atoms. Mg(1) is bonded in a 4-coordinate geometry to one O(10), one O(5), one O(6), and two equivalent O(9) atoms. There are eight inequivalent Tl sites. In the first Tl site, Tl(1) is bonded to one O(14), one O(5), two equivalent O(1), and two equivalent O(3) atoms to form a mixture of edge and corner-sharing TlO6 octahedra. The corner-sharing octahedral tilt angles are 50°. In the second Tl site, Tl(2) is bonded to one O(16), one O(2), two equivalent O(15), and two equivalent O(4) atoms to form a mixture of distorted edge and corner-sharing TlO6 octahedra. The corner-sharing octahedral tilt angles are 50°. In the third Tl site, Tl(3) is bonded in a 6-coordinate geometry to one O(7), one O(9), two equivalent O(10), and two equivalent O(5) atoms. In the fourth Tl site, Tl(4) is bonded in a see-saw-like geometry to one O(11), one O(4), and two equivalent O(8) atoms. In the fifth Tl site, Tl(5) is bonded to one O(13), one O(6), and two equivalent O(11) atoms to form TlO4 tetrahedra that share corners with two equivalent Tl(7)O6 octahedra and corners with two equivalent Tl(5)O4 tetrahedra. The corner-sharing octahedral tilt angles are 70°. In the sixth Tl site, Tl(6) is bonded to one O(10), one O(8), two equivalent O(12), and two equivalent O(7) atoms to form a mixture of distorted edge and corner-sharing TlO6 octahedra. The corner-sharing octahedral tilt angles are 61°. In the seventh Tl site, Tl(7) is bonded to one O(1), one O(15), two equivalent O(13), and two equivalent O(2) atoms to form TlO6 octahedra that share corners with two equivalent Tl(1)O6 octahedra, corners with two equivalent Tl(5)O4 tetrahedra, edges with two equivalent Tl(2)O6 octahedra, and edges with two equivalent Tl(7)O6 octahedra. The corner-sharing octahedral tilt angles are 50°. In the eighth Tl site, Tl(8) is bonded to one O(12), one O(3), two equivalent O(14), and two equivalent O(16) atoms to form a mixture of edge and corner-sharing TlO6 octahedra. The corner-sharing octahedral tilt angles range from 50-61°. There are sixteen inequivalent O sites. In the first O site, O(1) is bonded to one Ba(2), one Ba(4), one Tl(7), and two equivalent Tl(1) atoms to form distorted OBa2Tl3 trigonal bipyramids that share corners with two equivalent O(3)Ba2Tl3 square pyramids, corners with two equivalent O(1)Ba2Tl3 trigonal bipyramids,  a cornercorner with one O(9)BaMg2Tl trigonal pyramid,  an edgeedge with one O(3)Ba2Tl3 square pyramid, edges with two equivalent O(14)Ba2Tl3 square pyramids, and edges with two equivalent O(2)Ba2Tl3 trigonal bipyramids. In the second O site, O(2) is bonded to two equivalent Ba(2), one Tl(2), and two equivalent Tl(7) atoms to form a mixture of distorted edge and corner-sharing OBa2Tl3 trigonal bipyramids. In the third O site, O(3) is bonded to two equivalent Ba(1), one Tl(8), and two equivalent Tl(1) atoms to form a mixture of edge and corner-sharing OBa2Tl3 square pyramids. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to two equivalent Ba(1), one Tl(4), and two equivalent Tl(2) atoms. In the fifth O site, O(5) is bonded in a 6-coordinate geometry to two equivalent Ba(2), one Mg(1), one Tl(1), and two equivalent Tl(3) atoms. In the sixth O site, O(6) is bonded in a rectangular see-saw-like geometry to two equivalent Ba(2), one Mg(1), and one Tl(5) atom. In the seventh O site, O(7) is bonded to two equivalent Ba(1), one Tl(3), and two equivalent Tl(6) atoms to form distorted OBa2Tl3 trigonal bipyramids that share corners with two equivalent O(3)Ba2Tl3 square pyramids, corners with two equivalent O(16)Ba2Tl3 trigonal bipyramids,  a cornercorner with one O(9)BaMg2Tl trigonal pyramid,  an edgeedge with one O(3)Ba2Tl3 square pyramid, and edges with two equivalent O(7)Ba2Tl3 trigonal bipyramids. In the eighth O site, O(8) is bonded in a 5-coordinate geometry to one Ba(1), one Ba(3), one Tl(6), and two equivalent Tl(4) atoms. In the ninth O site, O(9) is bonded to one Ba(4), two equivalent Mg(1), and one Tl(3) atom to form distorted OBaMg2Tl trigonal pyramids that share corners with two equivalent O(14)Ba2Tl3 square pyramids,  a cornercorner with one O(1)Ba2Tl3 trigonal bipyramid,  a cornercorner with one O(7)Ba2Tl3 trigonal bipyramid, and corners with two equivalent O(9)BaMg2Tl trigonal pyramids. In the tenth O site, O(10) is bonded in a 6-coordinate geometry to two equivalent Ba(4), one Mg(1), one Tl(6), and two equivalent Tl(3) atoms. In the eleventh O site, O(11) is bonded to two equivalent Ba(3), one Tl(4), and two equivalent Tl(5) atoms to form a mixture of distorted edge and corner-sharing OBa2Tl3 square pyramids. In the twelfth O site, O(12) is bonded in a 5-coordinate geometry to two equivalent Ba(3), one Tl(8), and two equivalent Tl(6) atoms. In the thirteenth O site, O(13) is bonded in a 5-coordinate geometry to two equivalent Ba(4), one Tl(5), and two equivalent Tl(7) atoms. In the fourteenth O site, O(14) is bonded to two equivalent Ba(4), one Tl(1), and two equivalent Tl(8) atoms to form OBa2Tl3 square pyramids that share corners with two equivalent O(16)Ba2Tl3 trigonal bipyramids, corners with two equivalent O(9)BaMg2Tl trigonal pyramids, edges with two equivalent O(14)Ba2Tl3 square pyramids, edges with two equivalent O(3)Ba2Tl3 square pyramids,  an edgeedge with one O(16)Ba2Tl3 trigonal bipyramid, and edges with two equivalent O(1)Ba2Tl3 trigonal bipyramids. In the fifteenth O site, O(15) is bonded in a 5-coordinate geometry to two equivalent Ba(3), one Tl(7), and two equivalent Tl(2) atoms. In the sixteenth O site, O(16) is bonded to one Ba(1), one Ba(3), one Tl(2), and two equivalent Tl(8) atoms to form a mixture of distorted edge and corner-sharing OBa2Tl3 trigonal bipyramids. is represented by the CIF card [CIF]
data_Ba4MgTl8O16
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.534
_cell_length_b   12.895
_cell_length_c   3.627
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   91.042
_symmetry_Int_Tables_number   1
_cell_volume   492.588
_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
  Ba  Ba0  1  0.224  0.351  0.750  1.0
  Ba  Ba1  1  0.236  0.850  0.250  1.0
  Ba  Ba2  1  0.759  0.179  0.750  1.0
  Ba  Ba3  1  0.749  0.646  0.250  1.0
  Mg  Mg4  1  0.463  0.745  0.750  1.0
  Tl  Tl5  1  0.069  0.614  0.750  1.0
  Tl  Tl6  1  0.071  0.111  0.750  1.0
  Tl  Tl7  1  0.402  0.574  0.250  1.0
  Tl  Tl8  1  0.422  0.139  0.250  1.0
  Tl  Tl9  1  0.606  0.940  0.750  1.0
  Tl  Tl10  1  0.574  0.392  0.750  1.0
  Tl  Tl11  1  0.920  0.900  0.250  1.0
  Tl  Tl12  1  0.919  0.405  0.250  1.0
  O  O13  1  0.018  0.723  0.250  1.0
  O  O14  1  0.074  0.934  0.750  1.0
  O  O15  1  0.116  0.493  0.250  1.0
  O  O16  1  0.195  0.173  0.250  1.0
  O  O17  1  0.296  0.661  0.750  1.0
  O  O18  1  0.409  0.892  0.750  1.0
  O  O19  1  0.403  0.410  0.250  1.0
  O  O20  1  0.498  0.232  0.750  1.0
  O  O21  1  0.519  0.728  0.250  1.0
  O  O22  1  0.566  0.559  0.750  1.0
  O  O23  1  0.628  0.045  0.250  1.0
  O  O24  1  0.711  0.346  0.250  1.0
  O  O25  1  0.783  0.847  0.750  1.0
  O  O26  1  0.875  0.529  0.750  1.0
  O  O27  1  0.924  0.080  0.250  1.0
  O  O28  1  0.972  0.299  0.750  1.0
[/CIF]
.
The material described by Ba4MgTl8O16 crystallizes in the monoclinic Pm space group. There are four inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 8-coordinate geometry to one O(16), one O(8), two equivalent O(3), two equivalent O(4), and two equivalent O(7) atoms. In the second Ba site, Ba(2) is bonded in a 7-coordinate geometry to one O(1), two equivalent O(2), two equivalent O(5), and two equivalent O(6) atoms. In the third Ba site, Ba(3) is bonded in a 8-coordinate geometry to one O(16), one O(8), two equivalent O(11), two equivalent O(12), and two equivalent O(15) atoms. In the fourth Ba site, Ba(4) is bonded in a 8-coordinate geometry to one O(1), one O(9), two equivalent O(10), two equivalent O(13), and two equivalent O(14) atoms. Mg(1) is bonded in a 4-coordinate geometry to one O(10), one O(5), one O(6), and two equivalent O(9) atoms. There are eight inequivalent Tl sites. In the first Tl site, Tl(1) is bonded to one O(14), one O(5), two equivalent O(1), and two equivalent O(3) atoms to form a mixture of edge and corner-sharing TlO6 octahedra. The corner-sharing octahedral tilt angles are 50°. In the second Tl site, Tl(2) is bonded to one O(16), one O(2), two equivalent O(15), and two equivalent O(4) atoms to form a mixture of distorted edge and corner-sharing TlO6 octahedra. The corner-sharing octahedral tilt angles are 50°. In the third Tl site, Tl(3) is bonded in a 6-coordinate geometry to one O(7), one O(9), two equivalent O(10), and two equivalent O(5) atoms. In the fourth Tl site, Tl(4) is bonded in a see-saw-like geometry to one O(11), one O(4), and two equivalent O(8) atoms. In the fifth Tl site, Tl(5) is bonded to one O(13), one O(6), and two equivalent O(11) atoms to form TlO4 tetrahedra that share corners with two equivalent Tl(7)O6 octahedra and corners with two equivalent Tl(5)O4 tetrahedra. The corner-sharing octahedral tilt angles are 70°. In the sixth Tl site, Tl(6) is bonded to one O(10), one O(8), two equivalent O(12), and two equivalent O(7) atoms to form a mixture of distorted edge and corner-sharing TlO6 octahedra. The corner-sharing octahedral tilt angles are 61°. In the seventh Tl site, Tl(7) is bonded to one O(1), one O(15), two equivalent O(13), and two equivalent O(2) atoms to form TlO6 octahedra that share corners with two equivalent Tl(1)O6 octahedra, corners with two equivalent Tl(5)O4 tetrahedra, edges with two equivalent Tl(2)O6 octahedra, and edges with two equivalent Tl(7)O6 octahedra. The corner-sharing octahedral tilt angles are 50°. In the eighth Tl site, Tl(8) is bonded to one O(12), one O(3), two equivalent O(14), and two equivalent O(16) atoms to form a mixture of edge and corner-sharing TlO6 octahedra. The corner-sharing octahedral tilt angles range from 50-61°. There are sixteen inequivalent O sites. In the first O site, O(1) is bonded to one Ba(2), one Ba(4), one Tl(7), and two equivalent Tl(1) atoms to form distorted OBa2Tl3 trigonal bipyramids that share corners with two equivalent O(3)Ba2Tl3 square pyramids, corners with two equivalent O(1)Ba2Tl3 trigonal bipyramids,  a cornercorner with one O(9)BaMg2Tl trigonal pyramid,  an edgeedge with one O(3)Ba2Tl3 square pyramid, edges with two equivalent O(14)Ba2Tl3 square pyramids, and edges with two equivalent O(2)Ba2Tl3 trigonal bipyramids. In the second O site, O(2) is bonded to two equivalent Ba(2), one Tl(2), and two equivalent Tl(7) atoms to form a mixture of distorted edge and corner-sharing OBa2Tl3 trigonal bipyramids. In the third O site, O(3) is bonded to two equivalent Ba(1), one Tl(8), and two equivalent Tl(1) atoms to form a mixture of edge and corner-sharing OBa2Tl3 square pyramids. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to two equivalent Ba(1), one Tl(4), and two equivalent Tl(2) atoms. In the fifth O site, O(5) is bonded in a 6-coordinate geometry to two equivalent Ba(2), one Mg(1), one Tl(1), and two equivalent Tl(3) atoms. In the sixth O site, O(6) is bonded in a rectangular see-saw-like geometry to two equivalent Ba(2), one Mg(1), and one Tl(5) atom. In the seventh O site, O(7) is bonded to two equivalent Ba(1), one Tl(3), and two equivalent Tl(6) atoms to form distorted OBa2Tl3 trigonal bipyramids that share corners with two equivalent O(3)Ba2Tl3 square pyramids, corners with two equivalent O(16)Ba2Tl3 trigonal bipyramids,  a cornercorner with one O(9)BaMg2Tl trigonal pyramid,  an edgeedge with one O(3)Ba2Tl3 square pyramid, and edges with two equivalent O(7)Ba2Tl3 trigonal bipyramids. In the eighth O site, O(8) is bonded in a 5-coordinate geometry to one Ba(1), one Ba(3), one Tl(6), and two equivalent Tl(4) atoms. In the ninth O site, O(9) is bonded to one Ba(4), two equivalent Mg(1), and one Tl(3) atom to form distorted OBaMg2Tl trigonal pyramids that share corners with two equivalent O(14)Ba2Tl3 square pyramids,  a cornercorner with one O(1)Ba2Tl3 trigonal bipyramid,  a cornercorner with one O(7)Ba2Tl3 trigonal bipyramid, and corners with two equivalent O(9)BaMg2Tl trigonal pyramids. In the tenth O site, O(10) is bonded in a 6-coordinate geometry to two equivalent Ba(4), one Mg(1), one Tl(6), and two equivalent Tl(3) atoms. In the eleventh O site, O(11) is bonded to two equivalent Ba(3), one Tl(4), and two equivalent Tl(5) atoms to form a mixture of distorted edge and corner-sharing OBa2Tl3 square pyramids. In the twelfth O site, O(12) is bonded in a 5-coordinate geometry to two equivalent Ba(3), one Tl(8), and two equivalent Tl(6) atoms. In the thirteenth O site, O(13) is bonded in a 5-coordinate geometry to two equivalent Ba(4), one Tl(5), and two equivalent Tl(7) atoms. In the fourteenth O site, O(14) is bonded to two equivalent Ba(4), one Tl(1), and two equivalent Tl(8) atoms to form OBa2Tl3 square pyramids that share corners with two equivalent O(16)Ba2Tl3 trigonal bipyramids, corners with two equivalent O(9)BaMg2Tl trigonal pyramids, edges with two equivalent O(14)Ba2Tl3 square pyramids, edges with two equivalent O(3)Ba2Tl3 square pyramids,  an edgeedge with one O(16)Ba2Tl3 trigonal bipyramid, and edges with two equivalent O(1)Ba2Tl3 trigonal bipyramids. In the fifteenth O site, O(15) is bonded in a 5-coordinate geometry to two equivalent Ba(3), one Tl(7), and two equivalent Tl(2) atoms. In the sixteenth O site, O(16) is bonded to one Ba(1), one Ba(3), one Tl(2), and two equivalent Tl(8) atoms to form a mixture of distorted edge and corner-sharing OBa2Tl3 trigonal bipyramids. is represented by the CIF card [CIF]
data_Ba4MgTl8O16
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.534
_cell_length_b   12.895
_cell_length_c   3.627
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   91.042
_symmetry_Int_Tables_number   1
_cell_volume   492.588
_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
  Ba  Ba0  1  0.224  0.351  0.750  1.0
  Ba  Ba1  1  0.236  0.850  0.250  1.0
  Ba  Ba2  1  0.759  0.179  0.750  1.0
  Ba  Ba3  1  0.749  0.646  0.250  1.0
  Mg  Mg4  1  0.463  0.745  0.750  1.0
  Tl  Tl5  1  0.069  0.614  0.750  1.0
  Tl  Tl6  1  0.071  0.111  0.750  1.0
  Tl  Tl7  1  0.402  0.574  0.250  1.0
  Tl  Tl8  1  0.422  0.139  0.250  1.0
  Tl  Tl9  1  0.606  0.940  0.750  1.0
  Tl  Tl10  1  0.574  0.392  0.750  1.0
  Tl  Tl11  1  0.920  0.900  0.250  1.0
  Tl  Tl12  1  0.919  0.405  0.250  1.0
  O  O13  1  0.018  0.723  0.250  1.0
  O  O14  1  0.074  0.934  0.750  1.0
  O  O15  1  0.116  0.493  0.250  1.0
  O  O16  1  0.195  0.173  0.250  1.0
  O  O17  1  0.296  0.661  0.750  1.0
  O  O18  1  0.409  0.892  0.750  1.0
  O  O19  1  0.403  0.410  0.250  1.0
  O  O20  1  0.498  0.232  0.750  1.0
  O  O21  1  0.519  0.728  0.250  1.0
  O  O22  1  0.566  0.559  0.750  1.0
  O  O23  1  0.628  0.045  0.250  1.0
  O  O24  1  0.711  0.346  0.250  1.0
  O  O25  1  0.783  0.847  0.750  1.0
  O  O26  1  0.875  0.529  0.750  1.0
  O  O27  1  0.924  0.080  0.250  1.0
  O  O28  1  0.972  0.299  0.750  1.0
[/CIF]
.