Cummingtonite Yang H, Hazen R M, Prewitt C T, Finger L W, Lu R, Hemley R J American Mineralogist 83 (1998) 288-299 High-pressure single-crystal X-ray diffraction and infrared spectroscopic studies of the C2/m-P2_1/m phase transition in cummingtonite Sample: P = 5.09 GPa _database_code_amcsd 0001975 9.2993 17.8900 5.2321 90 102.979 90 P2_1/m atom x y z occ Biso Fe1 -.2497 .3364 .4800 .405 .57 Mg1 -.2497 .3364 .4800 .595 .57 Fe2 -.2522 .4253 .9785 .207 .77 Mg2 -.2522 .4253 .9785 .789 .77 Al2 -.2522 .4253 .9785 .004 .77 Fe3 -.2492 .25 .9829 .393 .71 Mg3 -.2492 .25 .9829 .607 .71 Fe4 -.2577 .5107 .4715 .927 .68 Mg4 -.2577 .5107 .4715 .035 .68 Ca4 -.2577 .5107 .4715 .038 .68 Si1A .0434 .3347 .2591 .56 Si1B .5464 .8330 .3051 .70 Si2A .0461 .4208 .7656 .72 Si2B .5545 .9167 .8084 .63 O1A -.1322 .3356 .1933 1.03 O1B .3700 .8370 .2262 .81 O2A -.1259 .4215 .6986 .55 O2B .3790 .9211 .7446 .68 O3A -.1292 .25 .6951 .75 O3B .3743 .75 .7300 .83 O4A .1241 .4993 .7863 .79 O4B .6333 .9933 .7536 .67 O5A .1096 .3718 .0281 .81 O5B .6098 .8918 .1170 .63 O6A .1126 .3817 .5277 .76 O6B .6038 .8561 .6099 .91 O7A .1066 .25 .3033 .96 O7B .6057 .75 .2616 .75