Reversible intercalation of graphite by fluorine and related synthetic and thermodynamic studies

Technical Report · Fri Jul 01 04:00:00 EDT 1983

OSTI ID:5484598

Mallouk, T E

The pentafluorogermanate salts of a variety of cations (ClO/sub 2//sup +/, NO/sup +/, SF/sub 3//sup +/, NO/sub 2//sup +/, and XeF/sub 5//sup +/) were synthesized and characterized by x-ray crystallographic and vibrational methods. The pentafluorogermanate ion was found to exist in one monomeric and at least three polymeric modifications in its salts. Lattice energy calculations and vapor pressure/temperature measurements established the following gas phase fluoride ion affinities: GeF/sub 4/, 100(6); BF/sub 3/, 92(6); AsF/sub 5/, 115(7); XeF/sub 5//sup +/, 202(7); ClF/sub 2//sup +/, 223(7); SF/sub 3//sup +/, 211(7); IF/sub 6//sup +/, 211(7) kcal mole/sup -1/. The electron affinities of the third row transition metal hexafluorides were likewise re-evaluated. The new graphite bifluorides, C/sub 12//sup +/HF/sub 2//sup -/ and C/sub 18//sup +/HF/sub 2//sup -/, were prepared; their crystal structures establish that they are correctly formulated as graphite salts. Fluorination of graphite in the presence of HF produced these salts and the first-stage hydrofluorides C/sub x/F/sub 1-delta/(HF)/sub delta/ (5 > x > 2, x/delta approx. = 12), which were studied by XPS, NMR, vibrational spectroscopy, and crystallographic methods. In these compounds, fluorine forms weak, semi-ionic bonds to the carbon atoms, which are disposed in virtually undistorted, planar sheets. For the range of composition in which C/sub x/F/sub 1-delta/(HF)/sub delta/ is an electrical conductor (x greater than or equal to 2.3), the fluorination was found to be electrochemically reversible.

• Research Organization: Lawrence Berkeley Lab., CA (USA)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 5484598
• Report Number(s): LBL-16778; ON: DE84004315
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360600* -- Other Materials
BORON COMPOUNDS
BORON FLUORIDES
CARBON
CLATHRATES
COMPLEXES
ELEMENTAL MINERALS
ELEMENTS
FLUORIDES
FLUORINE
FLUORINE COMPOUNDS
GERMANIUM COMPOUNDS
GERMANIUM FLUORIDES
GRAPHITE
HALIDES
HALOGEN COMPOUNDS
HALOGENS
HYDROFLUORIC ACID
HYDROGEN COMPOUNDS
INORGANIC ACIDS
MINERALS
NONMETALS