data_global
_amcsd_formula_title 'K2Ca2(SO4)3'
loop_
_publ_author_name
'Speer D'
'Salje E'
_journal_name_full 'Physics and Chemistry of Minerals'
_journal_volume 13 
_journal_year 1986
_journal_page_first 17
_journal_page_last 24
_publ_section_title
;
 Phase transitions in langbeinites I: Crystal chemistry
 and structures of K-double sulfates of the langbeinite
 type M2++K2(SO4)3, M++=Mg,Ni,Co,Zn,Ca
 Sample: K2Ca2(SO4)3, T = 260 C
;
_database_code_amcsd 0007370
_chemical_formula_sum 'K2 Ca2 S3 O12'
_cell_length_a 10.4289
_cell_length_b 10.4289
_cell_length_c 10.4289
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 90
_cell_volume 1134.267
_exptl_crystal_density_diffrn      2.615
_symmetry_space_group_name_H-M 'P 21 3'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '1/2-z,-x,1/2+y'
  '-z,1/2+x,1/2-y'
  '1/2+z,1/2-x,-y'
  'z,x,y'
  '1/2+y,1/2-z,-x'
  '1/2-y,-z,1/2+x'
  '-y,1/2+z,1/2-x'
  'y,z,x'
  '-x,1/2+y,1/2-z'
  '1/2+x,1/2-y,-z'
  '1/2-x,-y,1/2+z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
K1   0.81580   0.81580   0.81580
K2   0.05200   0.05200   0.05200
Ca1   0.33010   0.33010   0.33010
Ca2   0.58850   0.58850   0.58850
S1   0.22810   0.37460   0.00950
O1   0.31590   0.28050   0.95840
O2   0.10080   0.32240   0.00880
O3   0.23340   0.48440   0.92730
O4   0.26520   0.41560   0.13520