secondary cells with lithium anodes and immobilized fused_salt

The TI-F bond is lengthened over that in NF3 and the N=N bond is shortened compared
to tixt (1.24 1) in N2(CH3)2.
The N-F ar.d N=N bond energies of the trans form is
68 and 139 kcalfmol, respectively. The trans N2F2 is conveniently prepared by re-
Zction of N2F4 at 10~7 pressure with AlC13 at -80". The trans form is converted to
the form in over 90% yield at 75" in a well-passivated stainless steel cylinder.
?he N2Fp is obteined nearly quantitatively by the decomposition at 20" of the com-
:>lox KF"HNF2 formed at -80°C. Difluorodiazine has also been offered commercially.
'TI?€ cis W2F2 is more reactive chemically than trans N2F2, but both can act as fluorir.2ti.X
atepts. The so-called N=N double bond is unusually inert and does not
Ldcrgo cddition reactions. Detonations, especially with the cis isomer, have occurrcd
upon epplication of high pressure. The fluorination of N2F2 to N2F4 has
t?xrcrtly fiot been reported. %-N2F2 undergoes the fluoride abstraction with
Lewis -cids to give a stable salt of the N2F+ ion
T!ic isomer also gives this reaction with SbF5.
Tetrafluorohydrazine has the structure in the gas phase on the left below
(2 2nd 1 isomers) but the Tynretrical isomer on the right has also been observed in
the li?uid at 101; temperature.
i;-F Ii-11 1.53 1.39 8, F a I?@"
L F'NF 104'
L WTF 102O
diiiedral angle 69"
F
F
..
F
19F iMR -65.2,
-44.0,
-53.2,
-31.9 $
-60.4 6
(ill IF3 at -155")
Thc 2b:bnormally long N-N bond (compared to 1.45 in N2H4) has a low dissociation
cpcr,3 (25 kcalfmol) and N2F4 exists in equilibrium with stable NF2 radicals.
Tttrzflucrohydrazine has been available commercially since 1960 and its reactions
.?-.-c becr. studid ictensively. It enters into at least five types of reactions:
(1) normal 192 radical reactions including addition to olefins or a second radical,
xd -ibstraction reactions; (2) excited NF2 reactions resulting from photolysis at
obont 265' w; (3) fluorination (oxidation) reactions; (4) reduction reactions;
(5) fluoride abstraction reaction. Exmples of each are illustrated in Figure 2.
Trifluoramine oxide, IIF30, was reprted in 1965.
,
It can be prepared by
electric discharge at--19€i0 in mixtures of NF3 and 02 or OFg, by the flame fluori-
:.ztior. of I;O irith fast quench, or more conveniently at 25O by the fluorination of
ii0 with F2 photochemically or with certain metal hexafluorides such as IrF6. The
IZ3O hos a tetrahedral structure in which the N-F and N + 0 bonds are slightly