The compound described by SrCa2I6 is trigonal omega-derived structured and crystallizes in the monoclinic P2_1/c space group. Sr(1) is bonded to two equivalent I(1), two equivalent I(2), and two equivalent I(3) atoms to form SrI6 octahedra that share corners with four equivalent Ca(1)I6 pentagonal pyramids and edges with four equivalent Ca(1)I6 pentagonal pyramids. Ca(1) is bonded to two equivalent I(1), two equivalent I(2), and two equivalent I(3) atoms to form distorted CaI6 pentagonal pyramids that share corners with two equivalent Sr(1)I6 octahedra, corners with two equivalent Ca(1)I6 pentagonal pyramids, edges with two equivalent Sr(1)I6 octahedra, and edges with two equivalent Ca(1)I6 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 47-75°. There are three inequivalent I sites. In the first I site, I(1) is bonded in a T-shaped geometry to one Sr(1) and two equivalent Ca(1) atoms. In the second I site, I(2) is bonded in a distorted T-shaped geometry to one Sr(1) and two equivalent Ca(1) atoms. In the third I site, I(3) is bonded in a T-shaped geometry to one Sr(1) and two equivalent Ca(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_SrCa2I6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.055
_cell_length_b   7.419
_cell_length_c   14.679
_cell_angle_alpha   62.755
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   779.869
_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
  Sr  Sr0  1  0.000  0.000  0.000  1.0
  Sr  Sr1  1  0.500  0.000  0.500  1.0
  Ca  Ca2  1  0.604  0.670  0.255  1.0
  Ca  Ca3  1  0.104  0.330  0.245  1.0
  Ca  Ca4  1  0.896  0.670  0.755  1.0
  Ca  Ca5  1  0.396  0.330  0.745  1.0
  I  I6  1  0.327  0.706  0.091  1.0
  I  I7  1  0.810  0.570  0.093  1.0
  I  I8  1  0.427  0.060  0.264  1.0
  I  I9  1  0.927  0.940  0.236  1.0
  I  I10  1  0.310  0.430  0.407  1.0
  I  I11  1  0.827  0.294  0.409  1.0
  I  I12  1  0.173  0.706  0.591  1.0
  I  I13  1  0.690  0.570  0.593  1.0
  I  I14  1  0.073  0.060  0.764  1.0
  I  I15  1  0.573  0.940  0.736  1.0
  I  I16  1  0.190  0.430  0.907  1.0
  I  I17  1  0.673  0.294  0.909  1.0
[/CIF]
.
The compound described by SrCa2I6 is trigonal omega-derived structured and crystallizes in the monoclinic P2_1/c space group. Sr(1) is bonded to two equivalent I(1), two equivalent I(2), and two equivalent I(3) atoms to form SrI6 octahedra that share corners with four equivalent Ca(1)I6 pentagonal pyramids and edges with four equivalent Ca(1)I6 pentagonal pyramids. Ca(1) is bonded to two equivalent I(1), two equivalent I(2), and two equivalent I(3) atoms to form distorted CaI6 pentagonal pyramids that share corners with two equivalent Sr(1)I6 octahedra, corners with two equivalent Ca(1)I6 pentagonal pyramids, edges with two equivalent Sr(1)I6 octahedra, and edges with two equivalent Ca(1)I6 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 47-75°. There are three inequivalent I sites. In the first I site, I(1) is bonded in a T-shaped geometry to one Sr(1) and two equivalent Ca(1) atoms. In the second I site, I(2) is bonded in a distorted T-shaped geometry to one Sr(1) and two equivalent Ca(1) atoms. In the third I site, I(3) is bonded in a T-shaped geometry to one Sr(1) and two equivalent Ca(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_SrCa2I6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.055
_cell_length_b   7.419
_cell_length_c   14.679
_cell_angle_alpha   62.755
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   779.869
_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
  Sr  Sr0  1  0.000  0.000  0.000  1.0
  Sr  Sr1  1  0.500  0.000  0.500  1.0
  Ca  Ca2  1  0.604  0.670  0.255  1.0
  Ca  Ca3  1  0.104  0.330  0.245  1.0
  Ca  Ca4  1  0.896  0.670  0.755  1.0
  Ca  Ca5  1  0.396  0.330  0.745  1.0
  I  I6  1  0.327  0.706  0.091  1.0
  I  I7  1  0.810  0.570  0.093  1.0
  I  I8  1  0.427  0.060  0.264  1.0
  I  I9  1  0.927  0.940  0.236  1.0
  I  I10  1  0.310  0.430  0.407  1.0
  I  I11  1  0.827  0.294  0.409  1.0
  I  I12  1  0.173  0.706  0.591  1.0
  I  I13  1  0.690  0.570  0.593  1.0
  I  I14  1  0.073  0.060  0.764  1.0
  I  I15  1  0.573  0.940  0.736  1.0
  I  I16  1  0.190  0.430  0.907  1.0
  I  I17  1  0.673  0.294  0.909  1.0
[/CIF]
.