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: 11a, heat treated at 600 C
_database_code_amcsd 0001753
9.5048 18.1343 5.3077 90 102.009 90 P2_1/m
atom      x     y     z  occ  Biso
Fe1  -.2499 .3369 .4929 .258  .692
Mg1  -.2499 .3369 .4929 .742  .692
Fe2  -.2501 .4273 .9923 .165  .653
Mg2  -.2501 .4273 .9923 .828  .653
Al2  -.2501 .4273 .9923 .007  .653
Fe3  -.2497   .25 .9940 .220  .567
Mg3  -.2497   .25 .9940 .780  .567
Fe4  -.2510 .5089 .4903 .778  .931
Mg4  -.2510 .5089 .4903 .167  .931
Ca4  -.2510 .5089 .4903 .055  .931
Si1a  .0383 .3343 .2652       .514
Si2a  .0467 .4194 .7718       .539
Si1b  .5374 .8339 .2814       .524
Si2b  .5487 .9182 .7876       .549
O1a  -.1353 .3368 .2024       .586
O2a  -.1278 .4223 .7089       .739
O3a  -.1349   .25 .7006       .743
O4a   .1292 .4968 .7756       .923
O5a   .1001 .3756 .0421      1.052
O6a   .1021 .3756 .5371      1.213
O7a   .0945   .25 .2851      1.153
O1b   .3641 .8370 .2161       .688
O2b   .3742 .9229 .7262       .674
O3b   .3619   .75 .7143       .854
O4b   .6324 .9938 .7633       .927
O5b   .6017 .8847 .0794       .915
O6b   .5979 .8636 .5732       .972
O7b   .5927   .75 .2613       .841