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 2O
;
_database_code_amcsd 0001688
_chemical_formula_sum '(Ti.9 Zr.1) Si4 Na2 O13 H4'
_cell_length_a 16.3721
_cell_length_b 8.7492
_cell_length_c 7.4020
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 90
_cell_volume 1060.283
_exptl_crystal_density_diffrn      2.647
_symmetry_space_group_name_H-M 'P n c a'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '1/2+x,y,-z'
  '1/2-x,-y,z'
  'x,1/2-y,1/2+z'
  '-x,1/2+y,1/2-z'
  '1/2-x,1/2+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_occupancy
_atom_site_U_iso_or_equiv
Ti   0.00000   0.50000   0.00000   0.90000   0.03100
Zr   0.00000   0.50000   0.00000   0.10000   0.03100
Si1   0.08250   0.16130   0.12470   1.00000   0.03120
Si2   0.15670   0.43990   0.26030   1.00000   0.01610
Na   0.10230   0.69110   0.62200   1.00000   0.06300
O1   0.15990   0.26120   0.20060   1.00000   0.02500
O2   0.05010   0.03720   0.26950   1.00000   0.02800
O3   0.00740   0.27040   0.06330   1.00000   0.02500
O4   0.11620   0.05070  -0.03890   1.00000   0.03300
O5   0.11150   0.53940   0.10520   1.00000   0.02100
O6   0.25000   0.50000   0.27050   1.00000   0.01600
OW   0.19540   0.68440  -0.15480   1.00000   0.04900
H1   0.17300   0.58600  -0.10800   1.00000   0.10000
H2   0.24200   0.65000  -0.23200   1.00000   0.14000