The material described by NaCr12(Si2O7)4Br crystallizes in the tetragonal I4mm space group. The structure consists of two hydrogen bromide atoms inside a NaCr12(Si2O7)4 framework. In the NaCr12(Si2O7)4 framework, Na(1) is bonded in a distorted square co-planar geometry to four equivalent O(5) atoms. There are three inequivalent Cr sites. In the first Cr site, Cr(1) is bonded in a square co-planar geometry to two equivalent O(1) and two equivalent O(3) atoms. In the second Cr site, Cr(2) is bonded in a square co-planar geometry to two equivalent O(2) and two equivalent O(4) atoms. In the third Cr site, Cr(3) is bonded in a square co-planar geometry to two equivalent O(3) and two equivalent O(4) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(5), and two equivalent O(4) atoms to form corner-sharing SiO4 tetrahedra. In the second Si site, Si(2) is bonded to one O(2), one O(5), and two equivalent O(3) atoms to form corner-sharing SiO4 tetrahedra. There are five inequivalent O sites. In the first O site, O(5) is bonded in a distorted trigonal planar geometry to one Na(1), one Si(1), and one Si(2) atom. In the second O site, O(1) is bonded in a distorted trigonal planar geometry to two equivalent Cr(1) and one Si(1) atom. In the third O site, O(2) is bonded in a trigonal planar geometry to two equivalent Cr(2) and one Si(2) atom. In the fourth O site, O(3) is bonded in a distorted trigonal planar geometry to one Cr(1), one Cr(3), and one Si(2) atom. In the fifth O site, O(4) is bonded in a distorted trigonal planar geometry to one Cr(2), one Cr(3), and one Si(1) atom. is represented by the CIF card [CIF]
data_NaCr12Si8BrO28
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.913
_cell_length_b   9.913
_cell_length_c   9.913
_cell_angle_alpha   116.388
_cell_angle_beta   116.388
_cell_angle_gamma   96.379
_symmetry_Int_Tables_number   1
_cell_volume   721.578
_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
  Na  Na0  1  0.038  0.038  0.000  1.0
  Cr  Cr1  1  0.285  0.055  0.770  1.0
  Cr  Cr2  1  0.285  0.515  0.230  1.0
  Cr  Cr3  1  0.515  0.285  0.230  1.0
  Cr  Cr4  1  0.055  0.285  0.770  1.0
  Cr  Cr5  1  0.716  0.946  0.230  1.0
  Cr  Cr6  1  0.716  0.486  0.770  1.0
  Cr  Cr7  1  0.486  0.716  0.770  1.0
  Cr  Cr8  1  0.946  0.716  0.230  1.0
  Cr  Cr9  1  0.500  0.175  0.675  1.0
  Cr  Cr10  1  0.500  0.825  0.325  1.0
  Cr  Cr11  1  0.825  0.500  0.325  1.0
  Cr  Cr12  1  0.175  0.500  0.675  1.0
  Si  Si13  1  0.894  0.894  0.564  1.0
  Si  Si14  1  0.329  0.329  0.436  1.0
  Si  Si15  1  0.329  0.894  0.000  1.0
  Si  Si16  1  0.894  0.329  0.000  1.0
  Si  Si17  1  0.105  0.105  0.433  1.0
  Si  Si18  1  0.672  0.672  0.567  1.0
  Si  Si19  1  0.672  0.105  0.000  1.0
  Si  Si20  1  0.105  0.672  0.000  1.0
  Br  Br21  1  0.476  0.476  0.000  1.0
  O  O22  1  0.060  0.060  0.716  1.0
  O  O23  1  0.344  0.344  0.284  1.0
  O  O24  1  0.344  0.060  0.000  1.0
  O  O25  1  0.060  0.344  0.000  1.0
  O  O26  1  0.939  0.939  0.285  1.0
  O  O27  1  0.654  0.654  0.715  1.0
  O  O28  1  0.654  0.939  0.000  1.0
  O  O29  1  0.939  0.654  0.000  1.0
  O  O30  1  0.254  0.068  0.557  1.0
  O  O31  1  0.512  0.697  0.443  1.0
  O  O32  1  0.512  0.068  0.814  1.0
  O  O33  1  0.254  0.697  0.186  1.0
  O  O34  1  0.697  0.254  0.186  1.0
  O  O35  1  0.068  0.512  0.814  1.0
  O  O36  1  0.068  0.254  0.557  1.0
  O  O37  1  0.697  0.512  0.443  1.0
  O  O38  1  0.745  0.931  0.442  1.0
  O  O39  1  0.489  0.303  0.558  1.0
  O  O40  1  0.489  0.931  0.186  1.0
  O  O41  1  0.745  0.303  0.814  1.0
  O  O42  1  0.303  0.745  0.814  1.0
  O  O43  1  0.931  0.489  0.186  1.0
  O  O44  1  0.931  0.745  0.442  1.0
  O  O45  1  0.303  0.489  0.558  1.0
  O  O46  1  0.837  0.837  0.674  1.0
  O  O47  1  0.163  0.163  0.326  1.0
  O  O48  1  0.163  0.837  0.000  1.0
  O  O49  1  0.837  0.163  0.000  1.0
[/CIF]
.
The material described by NaCr12(Si2O7)4Br crystallizes in the tetragonal I4mm space group. The structure consists of two hydrogen bromide atoms inside a NaCr12(Si2O7)4 framework. In the NaCr12(Si2O7)4 framework, Na(1) is bonded in a distorted square co-planar geometry to four equivalent O(5) atoms. There are three inequivalent Cr sites. In the first Cr site, Cr(1) is bonded in a square co-planar geometry to two equivalent O(1) and two equivalent O(3) atoms. In the second Cr site, Cr(2) is bonded in a square co-planar geometry to two equivalent O(2) and two equivalent O(4) atoms. In the third Cr site, Cr(3) is bonded in a square co-planar geometry to two equivalent O(3) and two equivalent O(4) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(5), and two equivalent O(4) atoms to form corner-sharing SiO4 tetrahedra. In the second Si site, Si(2) is bonded to one O(2), one O(5), and two equivalent O(3) atoms to form corner-sharing SiO4 tetrahedra. There are five inequivalent O sites. In the first O site, O(5) is bonded in a distorted trigonal planar geometry to one Na(1), one Si(1), and one Si(2) atom. In the second O site, O(1) is bonded in a distorted trigonal planar geometry to two equivalent Cr(1) and one Si(1) atom. In the third O site, O(2) is bonded in a trigonal planar geometry to two equivalent Cr(2) and one Si(2) atom. In the fourth O site, O(3) is bonded in a distorted trigonal planar geometry to one Cr(1), one Cr(3), and one Si(2) atom. In the fifth O site, O(4) is bonded in a distorted trigonal planar geometry to one Cr(2), one Cr(3), and one Si(1) atom. is represented by the CIF card [CIF]
data_NaCr12Si8BrO28
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.913
_cell_length_b   9.913
_cell_length_c   9.913
_cell_angle_alpha   116.388
_cell_angle_beta   116.388
_cell_angle_gamma   96.379
_symmetry_Int_Tables_number   1
_cell_volume   721.578
_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
  Na  Na0  1  0.038  0.038  0.000  1.0
  Cr  Cr1  1  0.285  0.055  0.770  1.0
  Cr  Cr2  1  0.285  0.515  0.230  1.0
  Cr  Cr3  1  0.515  0.285  0.230  1.0
  Cr  Cr4  1  0.055  0.285  0.770  1.0
  Cr  Cr5  1  0.716  0.946  0.230  1.0
  Cr  Cr6  1  0.716  0.486  0.770  1.0
  Cr  Cr7  1  0.486  0.716  0.770  1.0
  Cr  Cr8  1  0.946  0.716  0.230  1.0
  Cr  Cr9  1  0.500  0.175  0.675  1.0
  Cr  Cr10  1  0.500  0.825  0.325  1.0
  Cr  Cr11  1  0.825  0.500  0.325  1.0
  Cr  Cr12  1  0.175  0.500  0.675  1.0
  Si  Si13  1  0.894  0.894  0.564  1.0
  Si  Si14  1  0.329  0.329  0.436  1.0
  Si  Si15  1  0.329  0.894  0.000  1.0
  Si  Si16  1  0.894  0.329  0.000  1.0
  Si  Si17  1  0.105  0.105  0.433  1.0
  Si  Si18  1  0.672  0.672  0.567  1.0
  Si  Si19  1  0.672  0.105  0.000  1.0
  Si  Si20  1  0.105  0.672  0.000  1.0
  Br  Br21  1  0.476  0.476  0.000  1.0
  O  O22  1  0.060  0.060  0.716  1.0
  O  O23  1  0.344  0.344  0.284  1.0
  O  O24  1  0.344  0.060  0.000  1.0
  O  O25  1  0.060  0.344  0.000  1.0
  O  O26  1  0.939  0.939  0.285  1.0
  O  O27  1  0.654  0.654  0.715  1.0
  O  O28  1  0.654  0.939  0.000  1.0
  O  O29  1  0.939  0.654  0.000  1.0
  O  O30  1  0.254  0.068  0.557  1.0
  O  O31  1  0.512  0.697  0.443  1.0
  O  O32  1  0.512  0.068  0.814  1.0
  O  O33  1  0.254  0.697  0.186  1.0
  O  O34  1  0.697  0.254  0.186  1.0
  O  O35  1  0.068  0.512  0.814  1.0
  O  O36  1  0.068  0.254  0.557  1.0
  O  O37  1  0.697  0.512  0.443  1.0
  O  O38  1  0.745  0.931  0.442  1.0
  O  O39  1  0.489  0.303  0.558  1.0
  O  O40  1  0.489  0.931  0.186  1.0
  O  O41  1  0.745  0.303  0.814  1.0
  O  O42  1  0.303  0.745  0.814  1.0
  O  O43  1  0.931  0.489  0.186  1.0
  O  O44  1  0.931  0.745  0.442  1.0
  O  O45  1  0.303  0.489  0.558  1.0
  O  O46  1  0.837  0.837  0.674  1.0
  O  O47  1  0.163  0.163  0.326  1.0
  O  O48  1  0.163  0.837  0.000  1.0
  O  O49  1  0.837  0.163  0.000  1.0
[/CIF]
.