Penkvilksite Merlino S, Pasero M, Artioli G, Khomyakov A P American Mineralogist 79 (1994) 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 2O _database_code_amcsd 0001688 16.3721 8.7492 7.4020 90 90 90 Pnca atom x y z occ Uiso Ti 0 .5 0 .9 .0310 Zr 0 .5 0 .1 .0310 Si1 .0825 .1613 .1247 .0312 Si2 .1567 .4399 .2603 .0161 Na .1023 .6911 .6220 .063 O1 .1599 .2612 .2006 .025 O2 .0501 .0372 .2695 .028 O3 .0074 .2704 .0633 .025 O4 .1162 .0507 -.0389 .033 O5 .1115 .5394 .1052 .021 O6 .25 .5 .2705 .016 OW .1954 .6844 -.1548 .049 H1 .173 .586 -.108 .10 H2 .242 .650 -.232 .14