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 = 41 kbar
Note: y-coordinate of O3 altered
_database_code_amcsd 0007377
8.587 14.912 4.5901 90 90 90 Cmc2_1
atom     x     y     z Biso
Be1  .1723 .0545  .136   .8
Be2  .3297 .2233  .065   .5
Si   .3270 .1128 .6499  .45
O1   .2956 .1233     0   .8
O2   .2048 .0443 .5034   .8
O3   .2990 .2086 .4846  1.1
O4       0 .5796 .5880   .7
OH1      0 .7628 .0533   .5
OH2      0 .0947 .0762   .6