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