AM_Penkvilksite_1 Formula: Ti Si4 Na2 O13 H4 Name: Penkvilksite Unit cell: 8.956 8.727 7.387 90.0 112.74 90.0 , V=532.48 Space group: P121/C1 (14)

Merlino S , Pasero M , Artioli G , Khomyakov A P , American Mineralogist , 79 (1994) p.1185-1193, 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