AM_Na33K67MgF3
Formula: (Na.33 K.67) Mg F3
Name: Na.33K.67MgF3
Unit cell: 3.9622 3.9622 3.9622 90.0 90.0 90.0 , V=62.20
Space group: PM3M (221)

Chakhmouradian A R , Ross K , Mitchell R H , Swainson I , Physics and Chemistry of Minerals , 28 (2001) p.277-284, The crystal chemistry of synthetic potassium-bearing neighborite, (Na1-xKx)MgF3, Sample x = .67