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 = 7.90 GPa
_database_code_amcsd 0001976
9.2099 17.7605 5.1930 90 103.173 90 P2_1/m
atom      x     y     z  occ Biso
Fe1  -.2510 .3359 .4736 .405  .59
Mg1  -.2510 .3359 .4736 .595  .59
Fe2  -.2516 .4249 .9756 .207  .64
Mg2  -.2516 .4249 .9756 .789  .64
Al2  -.2516 .4249 .9756 .004  .64
Fe3  -.2489   .25 .9755 .393  .62
Mg3  -.2489   .25 .9755 .607  .62
Fe4  -.2602 .5107 .4657 .927  .67
Mg4  -.2602 .5107 .4657 .035  .67
Ca4  -.2602 .5107 .4657 .038  .67
Si1A  .0454 .3342 .2561       .54
Si1B  .5502 .8329 .3118       .68
Si2A  .0458 .4214 .7618       .59
Si2B  .5558 .9163 .8132       .61
O1A  -.1305 .3360 .1873       .82
O1B   .3724 .8361 .2344       .68
O2A  -.1283 .4210 .6968       .79
O2B   .3821 .9208 .7480       .81
O3A  -.1251   .25 .6896       .71
O3B   .3728   .75 .7367       .76
O4A   .1222 .5022 .7859       .53
O4B   .6322 .9932 .7545       .83
O5A   .1117 .3692 .0176       .96
O5B   .6100 .8930 .1259       .90
O6A   .1134 .3842 .5194       .75
O6B   .6093 .8527 .6215       .59
O7A   .1118   .25 .3141       .93
O7B   .6091   .75 .2542       .44