The chemistry of neptunium fluorides in liquid anhydrous hydrogen fluoride. The isolation and characterization of NpF5

Abstract Pure NpF 5 is precipitated from solutions of the alkali metal salts, MNpF 6 , in liquid anhydrous hydrogen fluoride by acid-base displacement reaction with BF 3 NpF 5 has the αUF 5 structure. It decomposes rapidly only above 280°C to give NpF 6 and NpF 4 . On hydrolysis in 1 M HC10 4 it disproportionates to give NpF 4 and NpO ++ 2 . Characteristic optical spectra of the pure compound and the salts derived from it are given.