data_global
_chemical_name_mineral 'Sewardite'
loop_
_publ_author_name
'Roberts A C'
'Cooper M A'
'Hawthorne F C'
'Criddle A J'
'Stirling J A R'
_journal_name_full 'The Canadian Mineralogist'
_journal_volume 40 
_journal_year 2002
_journal_page_first 1191
_journal_page_last 1198
_publ_section_title
;
 Sewardite, CaFe2(AsO4)2(OH)2, the Ca-analogue of carminite,
 from Tsumeb, Namibia: Description and crystal structure
;
_database_code_amcsd 0005788
_chemical_compound_source 'Tsumeb, Namibia'
_chemical_formula_sum 'Ca Fe2 As2 O10 H2'
_cell_length_a 16.461
_cell_length_b 7.434
_cell_length_c 12.131
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 90
_cell_volume 1484.484
_exptl_crystal_density_diffrn      4.149
_symmetry_space_group_name_H-M 'C c c m'
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,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'
  '-x,-y,z'
  '1/2-x,1/2-y,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
Ca1   0.00000   0.00000   0.25000   0.01850
Ca2   0.25000   0.75000   0.00000   0.01010
Fe   0.37896   0.13210   0.13404   0.00560
As1   0.04504   0.74470   0.00000   0.00540
As2   0.21374   0.00000   0.25000   0.00480
O1   0.01440   0.22460   0.11190   0.00500
O2   0.08850   0.52900   0.00000   0.00600
O3   0.12190  -0.11400   0.00000   0.01200
O4   0.15110   0.17770   0.23890   0.01100
O5   0.27200  -0.01500   0.13780   0.00500
O-H6   0.17110   0.23300   0.00000   0.00500
O-H7   0.42430   0.00000   0.25000   0.01700