Perfluoroammonium salts of metal heptafluoride anions

Journal Article · Sat May 01 04:00:00 EDT 1982 · Inorg. Chem.; (United States)

DOI:https://doi.org/10.1021/ic00135a075· OSTI ID:5226022

Wilson, W W; Christe, K O

A method for the preparation of (NF/sub 4/)/sub 2/SiF/sub 6/ was discovered in which equilibrium 1 was successfully shifted to the right by repeatedly treating a highly concentrated NF/sub 4/HF/sub 2/-HF solution with an excess of SiF/sub 4/ while periodically stripping off the HF. (1) 2NF/sub 4/HF/sub 2/nHF + SiF/sub 4/ ..-->.. (nF/sub 4/)/sub 2/SiF/sub 6/ + 2 (H + 1) HF. This method was extended to the synthesis of NF/sub 4/WF/sub 7/ and NF/sub 4/UF/sub 7/ according to (2) and provided the first known examples of NF/sub 4//sup +/ salts containing complex anions with more than six ligands about their central atom. (2) NF/sub 4/HF/sub 2/.nHF + XF/sub 6/ ..-->.. NF/sub 4/XF/sub 7/ + (n + 1) HF (X = W, U). The infrared and Raman spectra of NF/sub 4/WF/sub 7/ and NF/sub 4/UF/sub 7/ establish beyond doubt the presence of NF/sub 4//sup +/ cations and WF/sub 7//sup -/ and UF/sub 7//sup -/ anions. The ionic nature of NF/sub 4/ X F/sub 7/ salts in BrF/sub 5/ solution was established by /sup 19/F NMR spectroscopy. The successful synthesis of NF/sub 4/WF/sub 7/ and NF/sub 4/UF/sub 7/ shows that even very weak Lewis acids such as metal hexafluorides are capable of forming stable NF/sub 4//sup +/ salts. This surprising result is a further manifestation of the unique properties of the NF/sub 4//sup +/ cation.

• Research Organization: Rocketdyne, Canoga Park, CA
• OSTI ID: 5226022
• Journal Information: Inorg. Chem.; (United States), Journal Name: Inorg. Chem.; (United States) Vol. 21:5; ISSN INOCA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400201* -- Chemical & Physicochemical Properties
400702 -- Radiochemistry & Nuclear Chemistry-- Properties of Radioactive Materials
ACTINIDE COMPLEXES
AMMONIUM COMPOUNDS
COMPLEXES
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
INFRARED SPECTRA
NMR SPECTRA
PHYSICAL PROPERTIES
RAMAN SPECTRA
SPECTRA
STRUCTURAL CHEMICAL ANALYSIS
SYNTHESIS
TRANSITION ELEMENT COMPLEXES
TUNGSTEN COMPLEXES
URANIUM COMPLEXES