The compound described by Ca2Tl2O5 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to one O(1), one O(2), one O(3), one O(5), and two equivalent O(4) atoms to form CaO6 octahedra that share  a cornercorner with one Tl(1)O6 octahedra, corners with two equivalent Tl(3)O6 octahedra,  an edgeedge with one Ca(1)O6 octahedra,  an edgeedge with one Tl(3)O6 octahedra, edges with two equivalent Tl(2)O6 octahedra, and edges with three equivalent Tl(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 2-63°. In the second Ca site, Ca(2) is bonded in a 7-coordinate geometry to one O(4), two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. There are three inequivalent Tl sites. In the first Tl site, Tl(1) is bonded to one O(1), one O(2), one O(3), one O(4), and two equivalent O(5) atoms to form TlO6 octahedra that share  a cornercorner with one Ca(1)O6 octahedra, corners with two equivalent Tl(2)O6 octahedra,  an edgeedge with one Tl(1)O6 octahedra,  an edgeedge with one Tl(2)O6 octahedra, edges with two equivalent Tl(3)O6 octahedra, and edges with three equivalent Ca(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-63°. In the second Tl site, Tl(2) is bonded to two equivalent O(2), two equivalent O(4), and two equivalent O(5) atoms to form TlO6 octahedra that share corners with four equivalent Tl(1)O6 octahedra, edges with two equivalent Tl(1)O6 octahedra, edges with two equivalent Tl(3)O6 octahedra, and edges with four equivalent Ca(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-14°. In the third Tl site, Tl(3) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(5) atoms to form TlO6 octahedra that share corners with four equivalent Ca(1)O6 octahedra, edges with two equivalent Ca(1)O6 octahedra, edges with two equivalent Tl(2)O6 octahedra, and edges with four equivalent Tl(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 2-14°. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Ca(1), two equivalent Ca(2), one Tl(1), and one Tl(3) atom to form distorted OCa3Tl2 trigonal bipyramids that share corners with three equivalent O(4)Ca3Tl3 octahedra,  a cornercorner with one O(5)CaTl4 square pyramid, corners with four equivalent O(3)Ca3Tl tetrahedra, corners with three equivalent O(1)Ca3Tl2 trigonal bipyramids, edges with two equivalent O(4)Ca3Tl3 octahedra, edges with two equivalent O(5)CaTl4 square pyramids,  an edgeedge with one O(3)Ca3Tl tetrahedra, and edges with three equivalent O(2)Ca3Tl2 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 9-42°. In the second O site, O(2) is bonded to one Ca(1), two equivalent Ca(2), one Tl(1), and one Tl(2) atom to form distorted OCa3Tl2 trigonal bipyramids that share  a cornercorner with one O(4)Ca3Tl3 octahedra, corners with three equivalent O(5)CaTl4 square pyramids, corners with four equivalent O(3)Ca3Tl tetrahedra, corners with three equivalent O(2)Ca3Tl2 trigonal bipyramids, edges with three equivalent O(4)Ca3Tl3 octahedra,  an edgeedge with one O(5)CaTl4 square pyramid,  an edgeedge with one O(3)Ca3Tl tetrahedra, and edges with three equivalent O(1)Ca3Tl2 trigonal bipyramids. The corner-sharing octahedral tilt angles are 41°. In the third O site, O(3) is bonded to one Ca(1), two equivalent Ca(2), and one Tl(1) atom to form OCa3Tl tetrahedra that share  a cornercorner with one O(4)Ca3Tl3 octahedra, corners with three equivalent O(5)CaTl4 square pyramids, corners with two equivalent O(3)Ca3Tl tetrahedra, corners with four equivalent O(1)Ca3Tl2 trigonal bipyramids, corners with four equivalent O(2)Ca3Tl2 trigonal bipyramids, edges with two equivalent O(4)Ca3Tl3 octahedra,  an edgeedge with one O(1)Ca3Tl2 trigonal bipyramid, and  an edgeedge with one O(2)Ca3Tl2 trigonal bipyramid. The corner-sharing octahedral tilt angles are 7°. In the fourth O site, O(4) is bonded to one Ca(2), two equivalent Ca(1), one Tl(1), one Tl(2), and one Tl(3) atom to form OCa3Tl3 octahedra that share corners with two equivalent O(4)Ca3Tl3 octahedra,  a cornercorner with one O(3)Ca3Tl tetrahedra,  a cornercorner with one O(2)Ca3Tl2 trigonal bipyramid, corners with three equivalent O(1)Ca3Tl2 trigonal bipyramids,  an edgeedge with one O(4)Ca3Tl3 octahedra, edges with four equivalent O(5)CaTl4 square pyramids, edges with two equivalent O(3)Ca3Tl tetrahedra, edges with two equivalent O(1)Ca3Tl2 trigonal bipyramids, and edges with three equivalent O(2)Ca3Tl2 trigonal bipyramids. The corner-sharing octahedra are not tilted. In the fifth O site, O(5) is bonded to one Ca(1), one Tl(2), one Tl(3), and two equivalent Tl(1) atoms to form OCaTl4 square pyramids that share corners with two equivalent O(5)CaTl4 square pyramids, corners with three equivalent O(3)Ca3Tl tetrahedra,  a cornercorner with one O(1)Ca3Tl2 trigonal bipyramid, corners with three equivalent O(2)Ca3Tl2 trigonal bipyramids, edges with four equivalent O(4)Ca3Tl3 octahedra,  an edgeedge with one O(5)CaTl4 square pyramid,  an edgeedge with one O(2)Ca3Tl2 trigonal bipyramid, and edges with two equivalent O(1)Ca3Tl2 trigonal bipyramids. is represented by the CIF file [CIF]
data_Ca2Tl2O5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   13.544
_cell_length_b   5.863
_cell_length_c   6.707
_cell_angle_alpha   73.478
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   510.558
_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
  Ca  Ca0  1  0.112  0.547  0.864  1.0
  Ca  Ca1  1  0.761  0.941  0.763  1.0
  Ca  Ca2  1  0.888  0.453  0.136  1.0
  Ca  Ca3  1  0.239  0.059  0.237  1.0
  Ca  Ca4  1  0.388  0.547  0.364  1.0
  Ca  Ca5  1  0.739  0.941  0.263  1.0
  Ca  Ca6  1  0.261  0.059  0.737  1.0
  Ca  Ca7  1  0.612  0.453  0.636  1.0
  Tl  Tl8  1  0.386  0.543  0.862  1.0
  Tl  Tl9  1  0.000  0.000  0.000  1.0
  Tl  Tl10  1  0.614  0.457  0.138  1.0
  Tl  Tl11  1  0.500  0.000  0.000  1.0
  Tl  Tl12  1  0.114  0.543  0.362  1.0
  Tl  Tl13  1  0.500  0.000  0.500  1.0
  Tl  Tl14  1  0.886  0.457  0.638  1.0
  Tl  Tl15  1  0.000  0.000  0.500  1.0
  O  O16  1  0.643  0.165  0.959  1.0
  O  O17  1  0.855  0.159  0.963  1.0
  O  O18  1  0.255  0.343  0.918  1.0
  O  O19  1  0.947  0.724  0.821  1.0
  O  O20  1  0.537  0.704  0.821  1.0
  O  O21  1  0.053  0.276  0.179  1.0
  O  O22  1  0.745  0.657  0.082  1.0
  O  O23  1  0.357  0.835  0.041  1.0
  O  O24  1  0.145  0.841  0.037  1.0
  O  O25  1  0.463  0.296  0.179  1.0
  O  O26  1  0.857  0.165  0.459  1.0
  O  O27  1  0.645  0.159  0.463  1.0
  O  O28  1  0.553  0.724  0.321  1.0
  O  O29  1  0.245  0.343  0.418  1.0
  O  O30  1  0.963  0.704  0.321  1.0
  O  O31  1  0.037  0.296  0.679  1.0
  O  O32  1  0.447  0.276  0.679  1.0
  O  O33  1  0.143  0.835  0.541  1.0
  O  O34  1  0.355  0.841  0.537  1.0
  O  O35  1  0.755  0.657  0.582  1.0
[/CIF]
.
The compound described by Ca2Tl2O5 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to one O(1), one O(2), one O(3), one O(5), and two equivalent O(4) atoms to form CaO6 octahedra that share  a cornercorner with one Tl(1)O6 octahedra, corners with two equivalent Tl(3)O6 octahedra,  an edgeedge with one Ca(1)O6 octahedra,  an edgeedge with one Tl(3)O6 octahedra, edges with two equivalent Tl(2)O6 octahedra, and edges with three equivalent Tl(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 2-63°. In the second Ca site, Ca(2) is bonded in a 7-coordinate geometry to one O(4), two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. There are three inequivalent Tl sites. In the first Tl site, Tl(1) is bonded to one O(1), one O(2), one O(3), one O(4), and two equivalent O(5) atoms to form TlO6 octahedra that share  a cornercorner with one Ca(1)O6 octahedra, corners with two equivalent Tl(2)O6 octahedra,  an edgeedge with one Tl(1)O6 octahedra,  an edgeedge with one Tl(2)O6 octahedra, edges with two equivalent Tl(3)O6 octahedra, and edges with three equivalent Ca(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-63°. In the second Tl site, Tl(2) is bonded to two equivalent O(2), two equivalent O(4), and two equivalent O(5) atoms to form TlO6 octahedra that share corners with four equivalent Tl(1)O6 octahedra, edges with two equivalent Tl(1)O6 octahedra, edges with two equivalent Tl(3)O6 octahedra, and edges with four equivalent Ca(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-14°. In the third Tl site, Tl(3) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(5) atoms to form TlO6 octahedra that share corners with four equivalent Ca(1)O6 octahedra, edges with two equivalent Ca(1)O6 octahedra, edges with two equivalent Tl(2)O6 octahedra, and edges with four equivalent Tl(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 2-14°. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Ca(1), two equivalent Ca(2), one Tl(1), and one Tl(3) atom to form distorted OCa3Tl2 trigonal bipyramids that share corners with three equivalent O(4)Ca3Tl3 octahedra,  a cornercorner with one O(5)CaTl4 square pyramid, corners with four equivalent O(3)Ca3Tl tetrahedra, corners with three equivalent O(1)Ca3Tl2 trigonal bipyramids, edges with two equivalent O(4)Ca3Tl3 octahedra, edges with two equivalent O(5)CaTl4 square pyramids,  an edgeedge with one O(3)Ca3Tl tetrahedra, and edges with three equivalent O(2)Ca3Tl2 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 9-42°. In the second O site, O(2) is bonded to one Ca(1), two equivalent Ca(2), one Tl(1), and one Tl(2) atom to form distorted OCa3Tl2 trigonal bipyramids that share  a cornercorner with one O(4)Ca3Tl3 octahedra, corners with three equivalent O(5)CaTl4 square pyramids, corners with four equivalent O(3)Ca3Tl tetrahedra, corners with three equivalent O(2)Ca3Tl2 trigonal bipyramids, edges with three equivalent O(4)Ca3Tl3 octahedra,  an edgeedge with one O(5)CaTl4 square pyramid,  an edgeedge with one O(3)Ca3Tl tetrahedra, and edges with three equivalent O(1)Ca3Tl2 trigonal bipyramids. The corner-sharing octahedral tilt angles are 41°. In the third O site, O(3) is bonded to one Ca(1), two equivalent Ca(2), and one Tl(1) atom to form OCa3Tl tetrahedra that share  a cornercorner with one O(4)Ca3Tl3 octahedra, corners with three equivalent O(5)CaTl4 square pyramids, corners with two equivalent O(3)Ca3Tl tetrahedra, corners with four equivalent O(1)Ca3Tl2 trigonal bipyramids, corners with four equivalent O(2)Ca3Tl2 trigonal bipyramids, edges with two equivalent O(4)Ca3Tl3 octahedra,  an edgeedge with one O(1)Ca3Tl2 trigonal bipyramid, and  an edgeedge with one O(2)Ca3Tl2 trigonal bipyramid. The corner-sharing octahedral tilt angles are 7°. In the fourth O site, O(4) is bonded to one Ca(2), two equivalent Ca(1), one Tl(1), one Tl(2), and one Tl(3) atom to form OCa3Tl3 octahedra that share corners with two equivalent O(4)Ca3Tl3 octahedra,  a cornercorner with one O(3)Ca3Tl tetrahedra,  a cornercorner with one O(2)Ca3Tl2 trigonal bipyramid, corners with three equivalent O(1)Ca3Tl2 trigonal bipyramids,  an edgeedge with one O(4)Ca3Tl3 octahedra, edges with four equivalent O(5)CaTl4 square pyramids, edges with two equivalent O(3)Ca3Tl tetrahedra, edges with two equivalent O(1)Ca3Tl2 trigonal bipyramids, and edges with three equivalent O(2)Ca3Tl2 trigonal bipyramids. The corner-sharing octahedra are not tilted. In the fifth O site, O(5) is bonded to one Ca(1), one Tl(2), one Tl(3), and two equivalent Tl(1) atoms to form OCaTl4 square pyramids that share corners with two equivalent O(5)CaTl4 square pyramids, corners with three equivalent O(3)Ca3Tl tetrahedra,  a cornercorner with one O(1)Ca3Tl2 trigonal bipyramid, corners with three equivalent O(2)Ca3Tl2 trigonal bipyramids, edges with four equivalent O(4)Ca3Tl3 octahedra,  an edgeedge with one O(5)CaTl4 square pyramid,  an edgeedge with one O(2)Ca3Tl2 trigonal bipyramid, and edges with two equivalent O(1)Ca3Tl2 trigonal bipyramids. is represented by the CIF file [CIF]
data_Ca2Tl2O5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   13.544
_cell_length_b   5.863
_cell_length_c   6.707
_cell_angle_alpha   73.478
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   510.558
_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
  Ca  Ca0  1  0.112  0.547  0.864  1.0
  Ca  Ca1  1  0.761  0.941  0.763  1.0
  Ca  Ca2  1  0.888  0.453  0.136  1.0
  Ca  Ca3  1  0.239  0.059  0.237  1.0
  Ca  Ca4  1  0.388  0.547  0.364  1.0
  Ca  Ca5  1  0.739  0.941  0.263  1.0
  Ca  Ca6  1  0.261  0.059  0.737  1.0
  Ca  Ca7  1  0.612  0.453  0.636  1.0
  Tl  Tl8  1  0.386  0.543  0.862  1.0
  Tl  Tl9  1  0.000  0.000  0.000  1.0
  Tl  Tl10  1  0.614  0.457  0.138  1.0
  Tl  Tl11  1  0.500  0.000  0.000  1.0
  Tl  Tl12  1  0.114  0.543  0.362  1.0
  Tl  Tl13  1  0.500  0.000  0.500  1.0
  Tl  Tl14  1  0.886  0.457  0.638  1.0
  Tl  Tl15  1  0.000  0.000  0.500  1.0
  O  O16  1  0.643  0.165  0.959  1.0
  O  O17  1  0.855  0.159  0.963  1.0
  O  O18  1  0.255  0.343  0.918  1.0
  O  O19  1  0.947  0.724  0.821  1.0
  O  O20  1  0.537  0.704  0.821  1.0
  O  O21  1  0.053  0.276  0.179  1.0
  O  O22  1  0.745  0.657  0.082  1.0
  O  O23  1  0.357  0.835  0.041  1.0
  O  O24  1  0.145  0.841  0.037  1.0
  O  O25  1  0.463  0.296  0.179  1.0
  O  O26  1  0.857  0.165  0.459  1.0
  O  O27  1  0.645  0.159  0.463  1.0
  O  O28  1  0.553  0.724  0.321  1.0
  O  O29  1  0.245  0.343  0.418  1.0
  O  O30  1  0.963  0.704  0.321  1.0
  O  O31  1  0.037  0.296  0.679  1.0
  O  O32  1  0.447  0.276  0.679  1.0
  O  O33  1  0.143  0.835  0.541  1.0
  O  O34  1  0.355  0.841  0.537  1.0
  O  O35  1  0.755  0.657  0.582  1.0
[/CIF]
.