Eucryptite
Pillars W W, Peacor D R
American Mineralogist 58 (1973) 681-690
The crystal structure of beta eucryptite as a function of temperature
T = 335 C
_database_code_amcsd 0000378
10.500 10.500 11.194 90 90 120 P6_422
atom     x     y     z Biso
Si1  .2502     0     0  .54
Si2  .2474 .4948     0  .73
Al1  .2530     0   1/2  .60
Al2  .2503 .5006   1/2  .78
Li1      0     0   1/2  3.2
Li2    1/2     0     0  2.7
Li3    1/2     0  .324  2.3
O1   .0870 .1945 .2454 1.24
O2   .6035 .7019 .2653 1.04
O3   .1061 .7109 .2585 2.58
O4   .5924 .2035 .2497 1.36