Cryptohalite
Bozorth R
Journal of the American Chemical Society 44 (1922) 1066-1070
The Crystal Structure of Ammonium Fluosilicate
_cod_database_code 1010992
_database_code_amcsd 0017907
8.38 8.38 8.38 90 90 90 Fm3m
atom    x   y   z
N1    .25 .25 .25
Si1     0   0   0
F1   .205   0   0