Neighborite
Chakhmouradian A R, Ross K, Mitchell R H, Swainson I
Physics and Chemistry of Minerals 28 (2001) 277-284
The crystal chemistry of synthetic potassium-bearing neighborite, (Na1-xKx)MgF3
Sample studied by neutron diffraction, x = .5
One of two alternative models
_database_code_amcsd 0008543
5.566 5.566 3.953 90 90 90 P4/mbm
atom     x     y   z occ Biso
Na       0    .5  .5  .5  1.1
K        0    .5  .5  .5  1.1
Mg       0     0   0      -.5
F1       0     0  .5     1.97
F2   .2596 .7596   0     1.96