Abstract:
Improved NF 4   +  compositions for solid propellant NF 3  -F 2  gas generators are described which produce NF 3  and F 2  free of gaseous Lewis acids and do not require clinker forming additives for their complexing. The novel self-clinkering compositions (NF 4 ) 2  SnF 6 , NF 4  SnF 5 , (NF 4 ) 2  TiF 6 , NF 4  Ti 2  F 9 , NF 4  Ti 3  F 13 , and NF 4  Ti 6  F 25  and processes for their production are disclosed.

Description:
The invention herein described was made in the course of or under a contract or subcontract thereunder, (or grant) with the United States Navy. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to compositions of matter and methods of producing the same and is particularly directed to improved solid propellant NF 3  -F 2  gas generators derived from self-clinkering NF 4   +  salts, together with methods for producing such gas generators. 
     2. Description of the Prior Art 
     NF 4   +  salts are the key ingredients for solid propellant NF 3  -F 2  gas generators, as shown by D. Pilipovich in U.S. Pat. No. 3,963,542. These propellants consist of a highly over-oxidized grain using NF 4   +  salts as the oxidizer. Burning these propellants with a small amount of fuel, such as aluminum powder, generates sufficient heat to thermally dissociate the bulk of the oxidizer. This is shown for NF 4  BF 4  in the following equation: 
     
         NF.sub.4 BF.sub.4 →NF.sub.3 +F.sub.2 +BF.sub.3 
    
     As can be seen from the equation the gaseous combustion products contain the volatile Lewis acid BF 3 . This disadvantage of a volatile Lewis acid byproduct is shared by all the previously known NF 4   +  compositions. These volatile Lewis acids possess a relatively high molecular weight and a low γ value (γ= C.sub. vi), relative to the preferred diluent helium and frequently act as a deactivator for the chemical HF-DF laser. Consequently, these volatile Lewis acids must be removed from the generated gas prior to its use in an efficient chemical laser. Based on the state of the art, heretofore, this would be achieved by adding a clinker forming agent, such as KF, to the solid propellant formulation. The function of this additive served to convert the volatile Lewis acid, such as BF 3 , to a non-volatile salt as shown by the following equation: 
     
         KF+BF.sub.3 →KBF.sub.4 
    
     The principal disadvantges of this approach are that, even if an excess of KF is used, complete clinkering cannot always be guaranteed, and that the addition of the KF severly degrades the yield of NF 3  -F 2  obtainable per pound of formulation. This problem could be solved by using NF 4   +  containing compositions derived from non-volatile Lewis acids. However, the synthesis of such compositions has previously been unknown, since highly stable and non-volatile Lewis acids are polymeric and contain coordination-wise saturated central atoms. Consequently, these compounds possess very little or no acidity, which renders the synthesis of such salts very difficult. 
     BRIEF SUMMARY AND OBJECTS OF THE INVENTION 
     The above described problem of obtaining a Lewis acid free NF 3  -F 2  gas stream from NF 4   +  compositions without clinker forming additives is overcome by the present invention. We have found that NF 4   +  salts, derived from the polymeric non-volatile Lewis acids SnF 4  (subliming at 704° C.) and TiF 4  (1 atm vapor pressure at 284° C.) can be prepared. The lack of acidity of SnF 4  at temperatures, at which NF 4   30   salts can be formed and exist, was demonstrated. It was shown that mixtures of NF 3 , F 2 , and SnF 4 , when heated to temperatures of up to 300° C. at autogenous pressures of about 150 atm, did not show any eevidence for NF 4   +  formation. 
     Since a direct synthesis of an NF 4   +  salt derived from SnF 4  was not possible, we have studied metathetical and displacement reactions. Because SnF 6   --  salts are stable in anhydrous HF, the metathetical and displacement reactions were carried out in this solvent. The following methathetical reaction 
     
         2NF.sub.4 SbF.sub.6 +Cs.sub.2 SnF.sub.6.sup.HF solution 2CsSbF.sub.6↓+(NF.sub.4).sub.2 SnF.sub.6 
    
     was carried out. It resulted in the precipitation of the rather insoluble salt CsSbF 6 , while the soluble (NF 4 ) 2  SnF 6  remained in solution. The two products were separated by a simple filtration step. The composition (in mol%) of the crude product was: (NF 4 ) 2  SnF 6 , 83; NF 4  SbF 6 , 13; CsSbF 6 , 4. The purity of this product can be easily increased by following the procedures outlined for NF 4  BF 4  in our co-pending application Ser. No. 731,198 filed Oct. 12, 1976, and now U.S. Pat. No. 4,107,275. 
     Another NF 4   +  salt derived from SnF 4  was obtained by the following quantitative displacement reaction in anhydrous HF as a solvent. 
     
         NF.sub.4 BF.sub.4 +SnF.sub.4.sup.HF solution NF.sub.4 SnF.sub.5 +BF.sub.3 
    
     for TiF 4 , the direct synthesis of an NF 4   +  salt from NF 3 , F 2 , and TiF 4  is still possible, since TiF 4  possesses already some vapor pressure at temperatures where NF 4   +  salts can be formed. However, the product thus obtained is very rich in TiF 4 , as shown by the following equation: ##STR1## The NF 4   +  content of this salt could not be significantly increased by any changes in the reaction conditions. 
     Displacement reactions between NF 4  BF 4  and TiF 4 , either in HF solution or in the absence of a solvent, produced NF 4   +  salts according to 
     
         NF.sub.4 BF.sub.4 +n TiF.sub.4 →NF.sub.4 TiF.sub.5.(n-1)TiF.sub.4 +BF.sub.3 
    
     where, depending on the exact reaction conditions, n equals either 3 or 2. 
     A further increase in the NF 4   +  content was possible by the following metathetical reaction which yielded (NF 4 ) 2  TiF 6  : 
     
         2nf.sub.4 sbF.sub.6 +Cs.sub.2 TiF.sub.6.sup.HF solution 2CsSbF.sub.6↓ +(NF.sub.4).sub.2 TiF.sub.6 
    
     the separation and purification procedure for this product is analogous to that outlined above for (NF 4 ) 2  SnF 6 . 
     The advantages of the above disclosed concept of using these novel self-clinkering NF 4   +  composition for NF 3  -F 2  gas generators become obvious from a comparison of their theoretical performance data. In Table I, the theoretical yields of usable fluorine, expressed in weight percent, of (NF 4 ) 2  SnF 6  and (NF 4 ) 2  TiF 6  are compared to that of KF clinkered NF 4  BF 4 , the highest performing presently known system. The novel self-clinkering compositions clearly outperform KF clinkered NF 4  BF 4 . Furthermore, the risk of incomplete clinkering which always exists for a clinkered formulation is avoided. 
     
                       TABLE I______________________________________A Comparison of the Theoretical Performanceof Self-clinkering (NF.sub.4).sub.2 SnF.sub.6 and(NF.sub.4).sub.2 TiF.sub.6 with KF-clinkered NF.sub.4 BF.sub.4System        Performance (Weight % Usable F)______________________________________NF.sub.4 BF.sub.4 . 1.2KF         38.5(NF.sub.4).sub.2 SnF.sub.6         46.0(NF.sub.4).sub.2 TiF.sub.6         55.6______________________________________ 
    
     Accordingly, it is an object of the present invention to provide higher performing solid propellant NF 3  -F 2  gas generator compositions. 
     Another object of the present invention is to provide self-clinkering NF 4   +  compositions capable of generating Lewis acid free NF 3  and F 2 . 
     Another object of the present invention is to provide processes for the production of self-clinkering NF 4   +  compositions. 
     These and other objects and features of the present invention will be apparent from the following examples. It is understood, however, that these examples are merely illustrative of the invention and should not be considered as limiting the invention in any sense. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     EXAMPLE I 
     Metathetical reactions were carried out in an apparatus consisting of three Teflon FEP U-traps interconnected by Monel unions and closed off at each end by a Monel valve. The union between trap II and trap III contained a Teflon filter and was held in place by a press fit. The passivated apparatus was taken to the dry box and Cs 2  SnF 6  and NF 4  SbF 6  (in a 1:2 mole ratio) were placed into traps I and II, respectively. The apparatus was connected to the vacuum line through flexible corrugated Teflon FEP tubing. Anhydrous HF, in an amount sufficient to just dissolve the starting materials, was added to traps I and II. Trap I was flexed to allow the Cs 2  SnF 6  solution to run into trap II containing the NF 4  SbF 6  solution. Upon contact of the two solutions, copious amounts of a white precipitate (CsSbF 6 ) formed. The contents of trap II were agitated for several minutes to obtain good mixing. Then the apparatus was inverted to allow the solution to run onto the filter. To generate a pressure differential across the filter, trap III was cooled to -80° C. After completion of the filtration step, trap III was warmed to ambient temperature and the HF solvent was pumped off. The solid residue on top of the filter consisted mainly of CsSbF 6 , whereas the solid collected in trap III was mainly the desired (NF 4 ) 2  SnF 6 . 
     The following example gives a typical product distribution obtainable with the above procedure and apparatus. Starting materials: NF 4  SbF 6  (9.72 mmol), Cs 2  SnF 6  (4.86 mmol); weight of solid on filter= 4.24 g; weight of solid in trap III= 1.36 g (weight calcd for 4.86 mmol of (NF 4 ) 2  SnF 6  = 2.01 g). Elemental analysis for solid from trap III. Found: NF 3 , 31.5; Sn, 25.1; Sb, 5.9; Cs, 1.3. Calculated analysis for a mixture (mol %) of 82.8 (NF 4 ) 2  SnF 6 , 12.9 NF 4  SbF 6 , and 4.3 CsSbF 6  : NF 3 , 31.72; Sn, 24.60; Sb, 5.24; Cs, 1.43. 
     (NF 4 ) 2  SnF 6  is a white, crystalline, hygroscopic solid, stable at room temperature but decomposing at 240° C. Its characteristic x-ray powder pattern is listed in Table II. Its ionic composition, i. e. the presence of discrete NF 4   +  cations and SnF 6   --  anions was established by  19  F nmr, infrared and Raman spectroscopy. 
     The  19  F nmr spectrum, recorded for a BrF 5  solution, showed in addition to the solvent lines a triplet of equal intensity with φ=-220, J NF=  229.6 Hz, and a line width at half height of about 5 Hz, which is characteristic of tetrahedral NF 4   + . In addition, a narrow singlet at φ=149 was observed with the appropriate .sup. 117/119Sn satellites (average J SnF  = 1549 Hz), characteristic of octahedral SnF 6   -- . The vibrational spectra of (NF 4 ) 2  SnF 6  and their assignments are summarized in Table III. 
     EXAMPLE II 
     A mixture of NF 4  BF 4  and SnF 4  (9.82 mmol each) was placed into a passivated Teflon-FEP ampoule containing a Teflon coated magnetic stirring bar. Anhydrous HF (10 ml liquid) was added at -78° C., and the resulting suspension was stirred at 25° C. for 2 hours. The volatile material was pumped off at 35° C. leaving behind a white stable solid which, on the basis of its weight (3.094 g) and Raman spectrum, consisted of 83 mol percent NF 4  SnF 5  and 17 mol percent unreacted starting materials. The HF treatment was repeated (again for 2 hours) and the non-volatile residue (2.980 g, weight calcd for 9.82 mmol of NF 4  SnF 5  =2.982 g) was shown by infrared, Raman, and  19  F nmr spectroscopy to be essentially pure NF 4  SnF 5 . Anal. Calcd for NF 4  SnF 5  : NF 3 , 23.38; Sn, 39.08. Found: NF 3 , 23.6; Sn, 38.7. 
     
                       TABLE II______________________________________X-RAY POWDER DATE FOR (NF.sub.4).sub.2 SnF.sub.6.sup.ad obsd      d calcd     Int       h k l______________________________________6.27        6.36        w         1 1 15.67        5.70        vs        0 0 24.99        5.04        vw        1 0 23.67        3.69        w         2 1 23.55        3.59        s         1 0 33.42        3.42        s         3 1 02.990       2.990       s         2 1 32.851       2.851       ms        0 0 42.492       2.490       m         3 3 12.347       2.356       w         3 2 32.230       2.228       s         4 2 22.120       2.123       mw        5 1 02.023       2.024       mw        5 0 21.961       1.963       w         4 0 41.917       1.914       m         4 4 01.882       1.881       mw        5 0 31.834       1.832       w         5 3 11.813       1.814       mw        4 4 21.763       1.765       vw        5 3 21.712       1.712       w         6 2 01.686       1.686       m         5 4 0,3 0 61.662       1.662       m         3 1 61.616       1.614       mw        6 3 01.570       1.570       mw        5 0 51.500       1.501       mw        6 4 01.397       1.396       mw        6 4 31.387       1.386       w         6 5 01.359       1.359       mw        7 0 6,5 4 51.331                   mw1.314                   mw1.263                   w1.231                   w1.212                   mw1.192                   w1.177                   mw______________________________________ .sup.a tetragonal, a = 10.828A, c = 11.406A, Cu K.sub.α radiation N filter 
    
     
                       TABLE III______________________________________VIBRATIONAL SPECTRA OF SOLID (NF.sub.4).sub.2 SnF.sub.6Obsd Freq (cm.sup.-1) andRel Inten         Assignments (Point Group)IR     Raman          NF.sub.4.sup.+ (T.sub.d)                            SnF.sub.6.sup.-- (O.sub.h)______________________________________1224 mw               2ν.sub.4 (A.sub.1`+ E + F.sub.2)1160 vs.  1158 (1.5)     ν.sub.3 (F.sub.2)1132 sh,vw                       ν.sub.1 + ν.sub.3 (F.sub.1u)1059 vw               ν.sub.2 + ν.sub.4 (F.sub.1 + F.sub.2)1026 vw                          ν.sub.2 + ν.sub.3 (F.sub.1u +                            F.sub.2u)  881 (0.1)      2ν.sub.2 (A.sub.1 + A.sub.2 + E)854 vvw  853 (10)       ν.sub.1 (A.sub.1)613 mw 613 (5.0)605 mw 607 (1.5)      ν.sub.4 (F.sub.2)  579 (8.3)                 ν.sub.1 (A.sub.1g)550 vs                           ν.sub.3 (F.sub.1u)  470 (0+) br               ν.sub.2 (E.sub.g)  449 (3.1)  442 (2.9)      ν.sub.2 (E)  251 (3.3)                 ν.sub.5 (F.sub.2g)  84 (0.3)       Lattice Vibration______________________________________ 
    
     NF 4  SnF 5  is a white, crystalline, hygroscopy solid, stable at room temperature and decomposing above 200° C. Its characteristic x-ray powder pattern is listed in Table IV. 
     
                       TABLE IV______________________________________X-RAY POWDER DATA FOR NF.sub.4 SnF.sub.5d obsd       Int       d obsd     Int______________________________________7.72         mw        2.571      mw6.32         vs        2.519      vw5.69         w         2.276      w5.29         w         2.146      w4.51         m         2.064      ms4.19         m         1.965      mw3.80         vs        1.929      w3.46         m         1.820      m3.32         m         1.780      mw3.17         mw        1.757      mw2.868        w         1.732      mw2.802        w         1.700      mw2.743        m         1.661      vw2.683        w         1.639      w                  1.615      w______________________________________ 
    
     its ionic structure, i.e., presence of NF 4   +  cations, was established by its  19  F nmr spectrum in BrF 5  solution. In addition to the solvent lines, it showed the triplet (see above) at φ=-220, characteristic of NF 4   + . Two resonances were observed for SnF 5   -  at φ=145.4 and 162.4, respectively, with an area ratio of 1:4. At -20° C. the resonances consisted of broad lines, but at lower temperatures the φ=162.4 signal showed splittings. Based on a more detailed analysis of these data, the SnF 5   -  anion appears to have a diameric or polymeric structure. The vibrational spectrum of NF 4  SnF 5  is listed in Table V and again establishes the presence of discrete NF 4   +  cations. 
     EXAMPLE III 
     When a mixture of NF 4  BF 4  and SnF 4  in a mol ratio of 2:1 was treated 8 times, as described in Example II, with liquid HF for a total of 35 days, the resulting non-volatile residue consisted mainly of NF 4  SnF 5 , unreacted NF 4  BF 4 , and only a small amount of (NF 4 ) 2  SnF 6 . 
     EXAMPLE IV 
     The metathetical synthesis of (NF 4 ) 2  TiF 6  from saturated HF solutions of NF 4  SbF 6  (10.00 mmol) and Cs 2  TiF 6  (5.00 mmol) was carried out in the apparatus described in Example I for the synthesis of (NF 4 ) 2  SnF 6 . After combination of the solutions of the two starting materials at room temperature and formation of a CsSbF 6  precipitate, the mixture was cooled to -78° C. and filtered. The volatile materials were pumped off at 50° C. for 1 hour. The filter cake (3.85 g) was shown by its x-ray powder diffraction pattern and vibrational spectroscopy to be mainly CsSbF 6  containing, due to the hold up of some mother liquor, a small amount of (NF 4 ) 2  TiF 6 . The filtrate residue (1.55 g, weight calcd for 5 mmol of (NF 4 ) 2  TiF 6  =1.71 g) had the composition (mol%): 88.5 (NF 4 ) 2  TiF 6  and 11.5 CsSbF 6 . Found: NF 3 , 36.2; Ti, 12.21; Sb, 4.11; Cs, 4.4. Calcd for a mixture of 88.5 (NF 4 ) 2  TiF 6  and 11.5 CsSbF 6  : NF 3 , 36.43; Ti, 12.29; Sb, 4.06; Cs, 4.43. Based on the observed Raman spectrum, the composition of the filtrate residue was estimated to be 90 (NF 4 ) 2  TiF 6  and 10 CsSbF 6 , in good agreement with the above elemental analysis. 
     (NF 4 ) 2  TiF 6  is a white, crystalline, hygroscopic solid, stable at room temperature, but decomposing above 200° C. Its characteristic x-ray powder pattern is listed in Table VI. 
     
                       TABLE V______________________________________VIBRATIONAL SPECTRA OF SOLID NF.sub.4 SnF.sub.5Obsd Freq (cm.sup.-1) and RelIntensNF.sub.4 SnF.sub.5     Assignments (Point Group)IR        Raman            NF.sub.4.sup.+ (T.sub.d)______________________________________1222 mw                      2ν.sub.4 (A.sub.1 + E + F.sub.2)         1168 (0.4)1165 vs       1159 (0.8)     ν.sub.3 (F.sub.2)         1150 sh1134 w,sh1061 w                        ν.sub.2 + ν.sub.4 (F.sub.1 + F.sub.2).                        -1048 w          811 (0.2)     2ν.sub.2 (A.sub.1 + A.sub.2 + E)850 wv         851 (10)      ν.sub.1 (A.sub.1)635 vs          622 (9.2)605 mw         606 (3.3)     ν.sub.4 (F.sub.2)575 vs          574 (0.5)559 w, sh      558 (2.0)490 m          490 (0+)458 m          448 (2.5)                        ν.sub.2 (E)          440 (2.3)          272 (0.6)          247 (1.4)          222 (1.1)          197 (0.6)          154 (0+)          135 (0.2)______________________________________ 
    
     
                       TABLE VI______________________________________X-RAY POWDER DATE FOR (NF.sub.4).sub.2 TiF.sub.6.sup.ad obsd      d calcd     Int       h k l______________________________________6.23        6.26        vw        1 1 15.57        5.56        vs        0 0 24.93        4.93        w         1 0 23.49        3.50        s         1 0 33.39        3.39        s         3 1 02.94        2.93        ms        2 1 32.782       2.778       m         0 0 42.465       2.463       w         3 3 12.315       2.318       mw        3 2 32.201       2.200       s         4 2 22.100       2.101       w         5 1 01.990       1.990       vw        5 2 0,5 0 21.892       1.894       m         4 4 01.789       1.789       mw        6 0 0,4 4 21.663       1.664       mw        2 2 61.641       1.644       mw        3 0 6______________________________________ .sup.a tetragonal, a = 10.715A, c = 11.114A, Cu K.sub.60  radiation Ni filter 
    
     Its ionic structure, i.e. the presence of discrete NF 4   +  cations and TiF 6   --  anions was established by  19  F nmr and vibrational spectroscopy. The  19  F nmr spectrum showed the triplet at φ=-220, characteristic for NF 4   +  as shown above, and the characteristic TiF 6   --  signal at φ=-81.7. The vibrational spectra are listed in Table VII. 
     
                       TABLE VII______________________________________VIBRATIONAL SPECTRA OF SOLID (NF.sub.4).sub.2 TiF.sub.6Obsd Freq (cm.sup.-1) andRel Intens     Assignments (Point Group)IR       Raman     NF.sub.4.sup.+ (T.sub.d)                            TiF.sub.6.sup.-- (O.sub.h)______________________________________1219 mw                  2ν.sub.4 (A.sub.1 + E + F.sub.2)1160 vs      1158   (1.4)1132 sh,vw               ν.sub.3 (F.sub.2)1060 vw                  ν.sub.2 + ν.sub.4 (F.sub.1 + F.sub.2)1021 w910  vw                              ν.sub.1 + ν.sub.4 (F.sub.1u)        883    (0.1)                    2ν.sub.2 (A.sub.1 + A.sub.2 + E)850  sh,vw   853    (10) ν.sub.1 (A.sub.1)804  w611  mw      612    (5)  ν.sub.4 (F.sub.2)        607    sh        601    (8.0)            ν.sub.1 (A.sub.1g)563  vs                              ν.sub.3 (F.sub.1u)452  vw      450    (3.3)        442    (2.6)                    ν.sub.2 (E)        289    (8.2)            ν.sub.5 (F.sub.2g)        107    (0+)  86   (2)    Lattice Vibrations______________________________________ 
    
     EXAMPLE V 
     TiF 4  (11.3 mmol), NF 3  (200 mmol), and F 2  (200 mmol) were heated in a passivated 90 ml Monel cylinder to various temperatures for different time periods. After each heating cycle, the volatile products were temporarily removed and the progress of the reaction was followed by determining the weight gain of the solid and recording its vibrational spectra. Heating to 200° C. for 3 days resulted in a weight gain of 8 mg and the vibrational spectra showed mainly unreacted TiF 4  in addition to a small amount of NF 4   +  and a polyperfluorotitanate (IV) anion (probably Ti 6  F 25   - ) having its strongest Raman line at 784 cm -1 . During the next two heating cycles (190°-195° C. for 14 days and 180° C. for 35 days) the solid gained 149 and 41 mg, respectively, in weight. The vibrational spectra did not show any evidence of unreacted TiF 4 , and the relative intensities of the bands due to NF 4   +  had significantly increased. Furthermore, the 784 cm -1  Raman line had become by far the most intense Raman line. Additional heating to 230° C. for 3 days did not result in significant changes in either the weight or the vibrational spectra of the solid. Based on the observed weight increase and on the lack of spectroscopic evidence for the presence of lower polyperfluorotitanate (IV) anions, the solid product appears to have the approximate composition NF 4  Ti 6  F 25  (calcd weight increase, 205 mg; obsd weight increase 198 mg). 
     EXAMPLE VI 
     Displacement reactions were carried out either in HF solution at room temperature or by heating the starting materials in the absence of a solvent in a Monel cylinder. For the HF solution reactions, the solid starting materials (6 mmol of NF 4  BF 4  in each experiment) were placed in a passivated Teflon FEP ampoule and 15 ml of liquid anhydrous HF was added. The mixture was stirred with a Teflon coated magnetic stirring bar at room temperature for a given time period. The volatile products were pumped off at 50° C. for 3 hours and the composition of the solid residue was determined by elemental and spectroscopic analyses and from the observed material balances. 
     The thermal displacement reactions were carried out in a prepassivated 90 ml Monel cylinder which was heated in an electric oven for a specified time period. The volatile products were separated by fractional condensation in a vacuum line, measured by PVT, and identified by infrared spectroscopy. The solid residues were weighed and characterized by elemental and spectroscopic analyses. The results of these experiments are summarized in Table VIII. 
     
                                           TABLE VIII__________________________________________________________________________Results from the Displacement Reactions between NF.sub.4 BF.sub.4 andTiF.sub.4Reactants (mol)          Reaction Conditions                    Products (mol)__________________________________________________________________________NF.sub.4 BF.sub.4 (6), untreated TiF.sub.4 (6)          HF, 24° C., 18h                    NF.sub.4 Ti.sub.2 F.sub.9 (4), NF.sub.4 BF.sub.4                    (4)NF.sub.4 BF.sub.4 (6), untreated TiF.sub.4 (12)          HF, 24° C., 72h                    NF.sub.4 Ti.sub.2 F.sub.9 (6)NF.sub.4 BF.sub.4 (6), prefluor. TiF.sub.4 (6)          HF, 24° C., 138h                    HF.sub.4 Ti.sub.3 F.sub.13 (˜2), NF.sub.4                    BF.sub.4 (˜4),                    small amount of NF.sub.4 TI.sub.2 F.sub.9NF.sub.4 BF.sub.4 (6), prefluor. TiF.sub.4 (12)          HF, 24° C., 96h                    NF.sub.4 Ti.sub.3 F.sub.13 (4), NF.sub.4                    BF.sub.4 (2),NF.sub.4 BF.sub.4 (6), untreated TiF.sub.4 (6)          190° C., 18h                    NF.sub.4 Ti.sub.2 F.sub.9 (˜3), NF.sub.3                    (˜3), BF.sub.3 (˜6),                    small amounts of NF.sub.4 BF.sub.4 and NF.sub.4                    Ti.sub.3 F.sub.13NF.sub.4 BF.sub.4 (6), untreated TiF.sub.4 (6)          160°  C., 60h                    NF.sub.4 Ti.sub.3 F.sub.13 (2),. NF.sub.4                    BF.sub.4 (1.4), NF.sub.3 (2.6),                    BF.sub.3 (4.6)NF.sub.4 BF.sub.4 (6), prefluor. TiF.sub.4 (6)          170° C., 20h                    NF.sub.4 Ti.sub.2 F.sub.9 (3), NF.sub.4 BF.sub.4                    (3), BF.sub.3 (3)NF.sub.4 BF.sub.4 (6), prefluor. TiF.sub.4 (12)          170° C., 20h                    NF.sub.4 Ti.sub.2 F.sub.9 (3.6), NF.sub.4                    Ti.sub.3 F.sub.13 (1.6),                    BF.sub.3 (5.4), NF.sub.4 BF.sub.4 (0.6)NF.sub.4 BF.sub.4 (6), prefluor. TiF.sub.4 (12)          170° C., 192h                    NF.sub.4 Ti.sub.2 F.sub.9 (6),__________________________________________________________________________                    BF.sub.3 (6) 
    
     Obviously, numerous variations and modifications may be made without departing from the present invention. Accordingly, it should be clearly understood that the forms of the present invention described above are illustrative only and are not intended to limit the scope of the present invention.