Biotite
Ohta T, Takeda H, Takeuchi Y
American Mineralogist 67 (1982) 298-310
Mica polytypism: Similarities in the crystal structures of coexisting 1M and
2M(1) oxybiotite
Sample: in the 2M1 setting
_database_code_amcsd 0000862
5.3175 9.212 19.976 90 95.09 90 C2/c
atom     x      y       z  occ B(1,1) B(2,2) B(3,3) B(1,2) B(1,3)  B(2,3)
Mg1    .75    .25       0 .612  .0051  .0015 .00071      0 .00014       0
Fe1    .75    .25       0 .200  .0051  .0015 .00071      0 .00014       0
Al1    .75    .25       0 .188  .0051  .0015 .00071      0 .00014       0
Mg2  .2321 .07750 -.00001 .513  .0077 .00186 .00068  .0016      0  .00009
Fe2  .2321 .07750 -.00001 .296  .0077 .00186 .00068  .0016      0  .00009
Ti2  .2321 .07750 -.00001 .168  .0077 .00186 .00068  .0016      0  .00009
Al2  .2321 .07750 -.00001 .023  .0077 .00186 .00068  .0016      0  .00009
Si1  .4624 .24902  .13850 .712  .0046  .0015 .00065  .0003 .00007       0
Al1  .4624 .24902  .13850 .280  .0046  .0015 .00065  .0003 .00007       0
Fe1  .4624 .24902  .13850 .008  .0046  .0015 .00065  .0003 .00007       0
Si2  .9645  .4163  .13857 .708  .0049  .0017 .00063  .0003 .00003  .00004
Al2  .9645  .4163  .13857 .264  .0049  .0017 .00063  .0003 .00003  .00004
Fe2  .9645  .4163  .13857 .028  .0049  .0017 .00063  .0003 .00003  .00004
K        0  .0832     .25       .0164  .0056 .00178      0 .00043       0
O11  .7421  .3139   .1664       .0102  .0047 .00089 -.0016  .0001  .00015
O21  .2416  .3512   .1677       .0103  .0045 .00088  .0024 -.0001 -.00032
O22  .4352  .0822   .1675       .0163  .0028 .00085 -.0001  .0008       0
O31  .4309  .2477  .05473       .0054  .0017 .00064  .0011  .0001  -.0001
O32  .9392  .4172  .05466       .0053  .0018 .00060  .0014      0  -.0001
O4   .9333  .0827  .04994       .0071  .0023 .00066  .0020      0  -.0003