data_global
_chemical_name_mineral 'Gypsum'
loop_
_publ_author_name
'Boeyens J C A'
'Ichharam V V H'
_journal_name_full 'Zeitschrift fur Kristallographie'
_journal_volume 217 
_journal_year 2002
_journal_page_first 9
_journal_page_last 10
_publ_section_title
;
 Redetermination of the crystal structure of calcium sulphate dihydrate, CaSO4*2H2O
;
_database_code_amcsd 0011093
_chemical_compound_source 'Synthetic'
_chemical_formula_sum 'Ca S O6 H4'
_cell_length_a 6.284
_cell_length_b 15.200
_cell_length_c 6.523
_cell_angle_alpha 90
_cell_angle_beta 127.41
_cell_angle_gamma 90
_cell_volume 494.899
_exptl_crystal_density_diffrn      2.311
_symmetry_space_group_name_H-M 'C 1 2/c 1'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '1/2+x,1/2+y,z'
  'x,-y,1/2+z'
  '1/2+x,1/2-y,1/2+z'
  '-x,y,1/2-z'
  '1/2-x,1/2+y,1/2-z'
  '-x,-y,-z'
  '1/2-x,1/2-y,-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_U_iso_or_equiv
Ca   0.50000   0.07956   0.75000 ?
S   0.00000   0.07724   0.75000 ?
O1   0.03720   0.13198   0.58720 ?
O2   0.24240   0.02211   0.90920 ?
OW   0.62020   0.18197   0.07840 ?
H1   0.74900   0.16200   0.25100   0.03100
H2   0.58400   0.23500   0.07300   0.05700
loop_
_atom_site_aniso_label
_atom_site_aniso_U_11
_atom_site_aniso_U_22
_atom_site_aniso_U_33
_atom_site_aniso_U_12
_atom_site_aniso_U_13
_atom_site_aniso_U_23
Ca 0.01050 0.01240 0.01040 0.00000 0.00570 0.00000
S 0.00840 0.01080 0.00900 0.00000 0.00460 0.00000
O1 0.01630 0.01870 0.01450 0.00060 0.00930 0.00520
O2 0.01150 0.01790 0.01720 0.00520 0.00750 0.00680
OW 0.03040 0.01820 0.01570 0.00130 0.00990 -0.00280