data_global
_chemical_name_mineral 'Penkvilksite'
loop_
_publ_author_name
'Merlino S'
'Pasero M'
'Artioli G'
'Khomyakov A P'
_journal_name_full 'American Mineralogist'
_journal_volume 79 
_journal_year 1994
_journal_page_first 1185
_journal_page_last 1193
_publ_section_title
;
 Penkvilksite, a new kind of silicate structure: OD character, X-ray
 single-crystal (1M), and powder Rietveld (2O) refinements of two MDO polytypes
 Note: polytype 1M
 Data has been corrected according to the ICSD
;
_database_code_amcsd 0001689
_chemical_formula_sum 'Ti Si4 Na2 O13 H4'
_cell_length_a 8.956
_cell_length_b 8.727
_cell_length_c 7.387
_cell_angle_alpha 90
_cell_angle_beta 112.74
_cell_angle_gamma 90
_cell_volume 532.482
_exptl_crystal_density_diffrn      2.608
_symmetry_space_group_name_H-M 'P 1 21/c 1'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  'x,1/2-y,1/2+z'
  '-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
Ti   0.00000   0.50000   0.00000   0.00720
Si1   0.15980   0.15990   0.19810   0.00810
Si2   0.31380   0.44230   0.40670   0.00820
Na   0.19280   0.69120   0.71360   0.02660
O1   0.31360   0.26210   0.34620   0.01240
O2   0.10320   0.03790   0.32020   0.01180
O3   0.02070   0.27810   0.06770   0.01190
O4   0.23470   0.05190   0.07040   0.01260
O5   0.20910   0.53870   0.21530   0.01090
O6   0.50000   0.00000   0.00000   0.01420
OW   0.36960   0.68880   0.02860   0.04510
H1   0.33000   0.60500   0.09300   0.17000
H2   0.48800   0.66700   0.06600   0.17000