data_global
_chemical_name_mineral 'Gypsum'
loop_
_publ_author_name
'Schofield P F'
'Knight K S'
'Stretton I C'
_journal_name_full 'American Mineralogist'
_journal_volume 81 
_journal_year 1996
_journal_page_first 847
_journal_page_last 851
_publ_section_title
;
 Thermal expansion of gypsum investigated by neutron powder diffraction
 T = 150 K
;
_database_code_amcsd 0001808
_chemical_formula_sum 'Ca S O6 D4'
_cell_length_a 5.6742
_cell_length_b 15.1236
_cell_length_c 6.5018
_cell_angle_alpha 90
_cell_angle_beta 118.495
_cell_angle_gamma 90
_cell_volume 490.357
_exptl_crystal_density_diffrn      2.387
_symmetry_space_group_name_H-M 'I 1 2/a 1'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '1/2+x,1/2+y,1/2+z'
  '-x,y,1/2-z'
  '1/2-x,1/2+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,-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   0.07984   0.25000   0.00262
S   0.00000   0.07695   0.75000   0.00300
O1   0.96371   0.13292   0.55070   0.00762
O2   0.75753   0.02170   0.66443   0.00656
Ow   0.38222   0.18229   0.46024   0.01007
D1   0.25341   0.16210   0.50655   0.02420
D2   0.40493   0.24446   0.49252   0.02189