Fluoro-eckermannite
Oberti R, Hawthorne F C, Camara F, Raudsepp M
American Mineralogist 84 (1999) 102-111
Unusual M3+ cations in synthetic amphiboles with nominal fluoro-eckermannite
composition: Deviations from stoichiometry and structural effects of the
cummingtonite component
Sample: Ga, Na.94Na1.07Mg.93Mg4.87Ga.13Si8O22F2
_database_code_amcsd 0002061
9.666 17.902 5.272 90 102.84 90 C2/m
atom       x     y     z occ Biso
Si(1)  .2844 .0849 .2836      .44
Si(2)  .2921 .1707 .7878      .56
Mg(1)      0 .0889    .5      .72
Ga(2)      0 .1798     0 .07  .77
Mg(2)      0 .1798     0 .93  .77
Mg(3)      0     0     0      .63
Mg(4)      0 .2643    .5 .47 1.84
Na(4)      0 .2643    .5 .53 1.84
NaA        0    .5     0 .26 2.63
NaA(m) .0444    .5 .1015 .35 2.78
O1     .1139 .0850 .2134      .47
O2     .1204 .1695 .7231      .79
F3     .1037     0 .7071      .73
O4     .3683 .2485 .7846     1.38
O5     .3504 .1284 .0696     1.56
O6     .3468 .1187 .5708     2.09
O7     .3456     0 .2838     1.15