Cummingtonite
Fischer K F
American Mineralogist 51 (1966) 814-818
A further refinement of the crystal structure of cummingtonite
(Mg,Fe)7(Si4O11)2(OH)2
_database_code_amcsd 0000145
9.51 18.19 5.33 90 101.9 90 C2/m
atom     x     y     z occ Biso
Si1  .2874 .0842 .2746      .36
Si2  .2977 .1688 .7817      .43
Mg1      0 .0872   1/2 .84  .38
Fe1      0 .0872   1/2 .16  .38
Mg2      0 .1773     0 .95  .36
Fe2      0 .1773     0 .05  .36
Mg3      0     0     0 .84  .30
Fe3      0     0     0 .16  .30
Mg4      0 .2597   1/2 .13  .79
Fe4      0 .2597   1/2 .87  .79
O1   .1135 .0874 .2087      .56
O2   .1232 .1721 .7193      .67
O3   .1134     0 .7067      .81
O4   .3798 .2460 .7716      .89
O5   .3514 .1310 .0659      .89
O6   .3488 .1185 .5597     1.01
O7   .3417     0 .2719      .88