Gonnardite
Lee Y, Hriljac J A, Vogt T
American Mineralogist 90 (2005) 247-251
Variable-temperature structural studies of tetranatrolite from Mt. Saint-Hilaire:
Synchrotron X-ray powder diffraction and Rietveld analysis
Sample: T = 200 C
12.9815 12.9815 6.6808 90 90 90 I-42d
atom     x     y     z  occ  Uiso
SiT1     0     0     0 .537 .0119
AlT1     0     0     0 .463 .0119
SiT2 .0564 .1340 .6224 .537 .0119
AlT2 .0564 .1340 .6224 .463 .0119
O1   .3842   .25  .125      .0206
O2   .1356 .0591 .4881      .0206
O3   .0533 .0950 .8650      .0206
Na   .6925   .25  .125 .731 .0240
Ca   .6925   .25  .125 .237 .0240
Wat4 .1258   .25  .125       .027
Wat5  .942   .25  .125 .051  .027