Heulandite-Ca
Gunter M E, Armbruster T, Kohler T, Knowles C R
American Mineralogist 79 (1994) 675-682
Crystal structure and optical properties of Na- and Pb-exchanged
heulandite-group zeolites
Sample: nonexchanged
Atomic parameters from ICSD
17.671 17.875 7.412 90 116.39 90 C2/m
atom     x     y     z  occ  Biso
Na1  .1549     0 .6666 .228   6.3
Ca1  .1549     0 .6666  .44   6.3
Ca2  .5402     0 .2031 .484  2.74
K    .2763     0   .01  .03   9.9
Na2  .2763     0   .01 .097   9.9
Si1  .1794 .1698 .0967 .753  1.34
Al1  .1794 .1698 .0967 .247  1.34
Si2  .2886 .0899 .5008 .753  1.42
Al2  .2886 .0899 .5008 .247  1.42
Si3  .2917 .3096 .2831 .753  1.35
Al3  .2917 .3096 .2831 .247  1.35
Si4  .0646 .2984  .411 .753  1.34
Al4  .0646 .2984  .411 .247  1.34
Si5      0 .2131     0 .753   1.4
Al5      0 .2131     0 .247   1.4
O1   .3048     0 .5466        2.8
O2   .2313 .1194 .6132       3.05
O3   .1833 .1543 .8842       3.22
O4   .2385 .1065 .2555       2.45
O5       0 .3259    .5        3.4
O6    .082 .1587 .0626       2.22
O7   .3729  .266 .4508       3.26
O8   .0089 .2662 .1842       2.78
O9   .2103 .2542 .1783       2.64
O10  .1155 .3723 .3988       2.64
OH11 .2763     0   .01  .83   9.9
OH12    .5     0    .5        7.9
OH13 .4228 .0817 .0307        5.4
OH14  .094     0  .285       13.2
OH15  .082  .005  .867  .43 11.84
OH16     0 .0873    .5       20.5