data_global
_chemical_name_mineral 'Portlandite'
loop_
_publ_author_name
'Henderson D M'
'Gutowsky H S'
_journal_name_full 'American Mineralogist'
_journal_volume 47 
_journal_year 1962
_journal_page_first 1231
_journal_page_last 1251
_publ_section_title
;
 A nuclear magnetic resonance determination of the hydrogen positions in Ca(OH)2
 T = 25 C
;
_database_code_amcsd 0000117
_chemical_formula_sum 'Ca O2 H2'
_cell_length_a 3.5925
_cell_length_b 3.5925
_cell_length_c 4.905
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 120
_cell_volume 54.823
_exptl_crystal_density_diffrn      2.244
_symmetry_space_group_name_H-M 'P -3 m 1'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '-y,-x,z'
  'y,-x+y,-z'
  '-x,-x+y,-z'
  '-x+y,-x,z'
  '-x+y,y,z'
  '-x,-y,-z'
  'y,x,-z'
  '-y,x-y,z'
  'x,x-y,z'
  'x-y,x,-z'
  'x-y,-y,-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
Ca   0.00000   0.00000   0.00000
O   0.33333   0.66667   0.23300
H   0.33333   0.66667   0.41800