Simpsonite
Ercit T S, Cerny P, Hawthorne F C
The Canadian Mineralogist 30 (1992) 663-671
The crystal chemistry of simpsonite
_database_code_amcsd 0005281
7.381 7.381 4.516 90 90 120 P3
atom     x     y    z U(1,1) U(2,2) U(3,3) U(1,2) U(1,3) U(2,3)
Ta   .1118 .3910    0  .0085  .0088  .0119  .0042  .0009  .0003
Al1   .423  .303 .496  .0120  .0149  .0139  .0059  .0014  .0007
Al2      0     0 .499  .0087  .0087  .0159      0      0      0
O1    .246  .062 .730  .0077  .0125  .0148 -.0002  .0020  .0007
O2    .392  .472 .777  .0261  .0464  .0154  .0295 -.0055 -.0070
O3    .192  .238 .274  .0231  .0146  .0111  .0102 -.0067 -.0024
O4    .482  .111 .265  .0112  .0239  .0210 -.0003  .0063  .0046
O5     1/3   2/3 .194  .0095  .0095  .0053  .0048      0      0
OH6    2/3   1/3 .691  .0354  .0354  .0098      0      0  .0177