Bertrandite
Hazen R M, Au A Y
Physics and Chemistry of Minerals 13 (1986) 69-78
High-pressure crystal chemistry of phenakite (Be2SiO4)
and bertrandite (Be4Si2O7(OH)2)
Sample: P = 23 kbar
Note: x-coordinate of O2 altered
_database_code_amcsd 0007376
8.641 15.051 4.5338 90 90 90 Cmc2_1
atom     x     y     z Biso
Be1  .1679 .0536  .094   .6
Be2  .3246 .2214  .061  .06
Si   .3261 .1135 .6546  .52
O1   .2939 .1246     0   .8
O2   .2067 .0438 .4987  1.0
O3   .2948 .2081 .4904   .9
O4       0 .5821 .5843   .9
OH1      0 .7600 .0826  .87
OH2      0 .0916 .0760   .6