Rankamaite
Atencio D, Contreira R R, Mills S J, Coutinho J M V,
Honorato S B, Ayala A P, Ellena J, De Andrade M B
American Mineralogist 96 (2011) 1455-1460
Rankamaite from the Urubu pegmatite, Itinga, Minas Gerais,
Brazil: Crystal chemistry and Rietveld refinement
Note: Identification of OH not reported
Locality: Urubu pegmatite, Itinga, Minas Gerais, Brazil
_database_code_amcsd 0018556
17.224 17.687 3.9361 90 90 90 C222
atom      x      y  z occ Biso
K1    .8322      0 .5 .63  4.5
Na2   .4990      0 .5 .43  4.5
Na3     .25    .25 .5 .68  4.5
Ta1       0      0  0 .71    2
Nb1       0      0  0 .29    2
Ta2       0 .67188  0 .72    2
Nb2       0 .67188  0 .28    2
Ta3  .18037 .39406  0 .85    2
Al3  .18037 .39406  0 .15    2
Ta4  .11190 .82225  0 .89    2
Nb4  .11190 .82225  0 .11    2
O1    .3235  .1061 .5        1
O2    .6165  .6777 .5        1
O3    .1376  .2915  0        1
O4    .0711  .5780  0        1
O5    .2790  .3377  0        1
O6    .1103  .9442  0        1
O7        0  .3334 .5        1
O8        0  .2011  0        1
O9    .7108      0  0        1
O10       0      0 .5        1