Cummingtonite
Yang H, Hirschmann M M
American Mineralogist 80 (1995) 916-922
Crystal structure of P2_1/m ferromagnesian amphibole and the role of cation
ordering and composition in the P2_1/m - C2/m transition in cummingtonite
Sample: 1c, heat treated at 700 C
_database_code_amcsd 0001754
9.5057 18.1187 5.3059 90 102.031 90 P2_1/m
atom      x     y     z  occ  Biso
Fe1  -.2493 .3369 .4923  .25  .673
Mg1  -.2493 .3369 .4923  .75  .673
Fe2  -.2501 .4273 .9914 .163  .650
Mg2  -.2501 .4273 .9914 .830  .650
Al2  -.2501 .4273 .9914 .007  .650
Fe3  -.2495   .25 .9933 .221  .544
Mg3  -.2495   .25 .9933 .789  .544
Fe4  -.2517 .5089 .4897 .713  .916
Mg4  -.2517 .5089 .4897 .237  .916
Ca4  -.2517 .5089 .4897 .050  .916
Si1a  .0386 .3344 .2649       .614
Si2a  .0461 .4194 .7710       .575
Si1b  .5368 .8339 .2818       .499
Si2b  .5491 .9183 .7880       .595
O1a  -.1354 .3368 .2025       .747
O2a  -.1275 .4228 .7075       .655
O3a  -.1362   .25 .7009       .773
O4a   .1285 .4972 .7774       .965
O5a   .1011 .3751 .0403      1.074
O6a   .1036 .3756 .5360      1.126
O7a   .0951   .25 .2865       .887
O1b   .3640 .8371 .2163       .636
O2b   .3740 .9229 .7267       .783
O3b   .3634   .75 .7160       .979
O4b   .6326 .9937 .7620       .873
O5b   .6004 .8850 .0801       .920
O6b   .5965 .8633 .5744      1.093
O7b   .5918   .75 .2593      1.167