S.N. Spirin

“Clathrates” (?) of noble-gas fluorides

Abstract Reactions between gold pentafluoride and alkali-earth metals fluorides in non-aqueous hydrogen fluoride were investigated. Ca(AuF 6 ) 2 , Sr(AuF 6 ) 2 and Ba(AuF 6 ) 2 were identified. The Raman spectra of the received compounds were examined in crystalline form and in the non-aqueous HF solution. It was found out, that bis-hexafluoroaurates had high solubility in non-aqueous HF. The Raman spectra of liquid system HFM II (AuF 6 )KrF 2 were investigated. The compounds of variable composition on KrF 2 , where n=1+4 (Ba, Sr) and n=1+3 (Ca) were crystallized from this system, if the solvent were evaporated slowly. The results of Raman spectra analyses of obtained compounds are presented. Interaction between KrF 2 and M II (AuF 6 ) 2 leads to essential increase of vibrational frequency of KrF bond (up to 35 cm −1 ) comparing with KrF 2 (462 cm −1 ) and to the splitting of vibrational bond. This interaction decreases with increase of n; the possible nature of interaction is discussed. The received compounds are characterized by higher thermal stability of the “bonded” KrF 2 . If heated up to 350 K KrF 2 may be quantatively obtained from the salts. If heated quickly up to 370+380 K the salts decomposes with explosion. The energy aspect of the complex salts formation is discussed. The results of interaction between M II (AuF 6 ) 2 and xenon fluorides will be also presented.

Synthesis and Spectral Properties of Hexafluoroaurates

It is established that krypton difluoride (KrF2) interacts with metallic gold in anhydrous hydrogen fluoride (HF) in the presence of alkaline and alkaline-earth metal fluorides with the formation of complex hexafluoroaurates with the general formula MIAuVF6 (MI = Li, Na, K, Rb, Cs) and bis-hexafluoroaurates MII(AuVF6)2 (MII = Mg, Ca, Sr, Ba). As a result of the subsequent interaction of bis-hexafluoroaurates with krypton difluoride, new coordination compounds with the composition MII(AuVF6)2 · nKrF2 (MII = Ca, Sr, Ba; n = 0–4) were synthesized. The Raman spectra were studied and a comparative analysis of the Raman spectra of the obtained compounds was performed. The possible variants of the structural transformation of the AuF6− anions in compounds and the position and character of the chemical bond of the “guest” (KrF2) in these compounds are discussed.

Thermochemistry of certain hexafluorometalates and tetrafluoroborates

Abstract The enthalpies of formation of K 2 NiF 6 , CaNiF 6 , (NO 2 ) 2 NiF 6 , (ClOF 2 ) 2 MnF 6 , (ClOF 2 ) 2 NiF 6 , ClOF 2 BF 4 , XeF 5 BF 4 were determined from the enthalpies of reactions with water and aqueous sodium hydroxide (0.1 N) by liquid calorimetry. The latter compounds were prepared by reactions ClOF 3 and XeF 6 with BF 3 at moderate temperatures. Other compounds were prepared by using of synthesis and purifications methods developed in our laboratory — in KrF 2 solutions in arid HF [1]. Obtained for δH 298 (reaction with H 2 O) and recommended values for δH∘ f298 studied compounds are (kJ·mole −1 ): 1 . Substance ΔH 298 Δ° f298 K 2 NiF 6 −246.8±0.7 −2010±7 CANIF 6 −363.8±5 −1951±7 XeF 5 BF 4 −404.7±4.8 −1549±5 ClOF 2 BF 4 −388±2.3 −1363±10 (NO 2 ) 2 NiF 6 −471±5.0 −1116±12 (ClOF 2 ) 2 NiF 6 −968.2±7.8 −1133±10 (ClOF 2 MnF 6 −669±11 −1608±13 For these compounds reactions with H 2 O are represented by following equations: NiF 6 2- + H 2 O = 2F − (sol) + NiF 2 (sol) + 2HF (sol) + 0.50 2 (g) ClOF 2 + + 2H 2 O = HClO 3(sol) + 2HF (sol) NO 2 + + H 2 O = HNO 3(sol) + 2HF (sol) XeF 5 BF 4(s) + 3H 2 O = XeO 3(sol) + 5HF (sol) + H[BF 4 ] (sol) ClOF 2 BF 4(s) + 2H 2 O = HClO 3(sol) + H[BF 4 ] (sol) + HF (sol)

Investigation of ClOF3HF interaction in liquid Xe

Abstract The system ClOF3HF (T=293 K) was studied formerly by means of Raman spectroscopy [Sh. Sh. Nabiev, I.I. Ostroukhova, A.V. Ryzhkov, V.B. Sokolov and S.N. Spirin, J. Fluorine Chem., 54 (1991) 333]. On the basis of polarization measurement results it was shown that in this system strong intermolecular interactions are accompanied by considerable ionization of the solute. The present work is devoted to the investigation of infrared spectra of ClOF3HF system in liquid xenon solution at T=180 K. The bands corresponding to ClF, ClO and HF bond vibrations were studied. The mechanisms of ClOF2+ and HF2− band contour formation were discussed.

Complex salts of gold pentafluoride

Abstract The results of synthesis research and vibrational spectra examination of complex compounds of gold pentafluoride, namely NOF 2 AuF 6 , NF 4 AuF 6 , ClOF 2 AuF 6 , ClO 2 AuF 6 , ClF 2 AuF 6 , ClF 4 AuF 6 , OsF 6 AuF 6 and H 3 OAuF 6 are presented. Synthesis of NOF 2 AuF 6 , ClOF 2 AuF 6 , ClO 2 AuF 6 , ClF 2 AuF 6 and ClF 4 AuF 6 were carried out by mixing the initial components in HF. Synthesis of NF 4 AuF 6 and OsF 6 AuF 6 were carried out by treatment of the mixtures of NF 3 +Au and Os+Au by krypton difluoride in anhydrous hydrogen fluoride. The assignment of AuF 6 − anion frequencies in vibrational spectra was made assuming a slightly distorted octahedron structure, and assignment of cation frequencies assuming C 2v (NOF 2 + , ClOF 2 + , ClO 2 + , ClF 4 + ), T d (NF 4 + ) and O h (OsF 6 + ) symmetry. The characteristic features of the vibrational spectra of AuF 5 complex compounds were determined. Evaluations of force field constants of the cations and anions were carried out. The interactions between the said gold pentafluoride complex compounds and water were investigated by means of Raman spectroscopy.

Fluorination of polysulfone

Abstract Fluorination of aromatic polysulfone film was achieved by treatment with XeF2 vapors. Swelling tests in certain industrial liquids and fuels showed substantial decrease in swelling of the fluorinated films. The influence of a catalyst on the fluorination process was examined. Results of gravimetric measurements, bulk analysis and ESCA-spectroscopy of the treated samples will be presented as well as the values of certain mechanical properties of the fluorinated films. The optimum time and conditions of the fluorination process for aromatic polysulfone film were determined.

Synthesis methods of fluorocontaining compounds

Experimental studies carried out resulted in the new methods of synthesis of inorganic fluorides,which satisfied practically by all the above mentioned demands: 1. Method of synthesis using catalytic-thermal generation of atomic fluorine from molecular fluorine. 2. Method of synhtesis using as fluorinating aqents such substances, so-called “carriers” of atomic fluorine, as O2F2 and KrF2. 3. Method of synthesis in solutions of fluor-oxidants (O2F2, KrF2, XeF2, XeF4) in non-aqueous hydrogen fluoride and bromine pentafluoride. Synthesis methods of fluorocontaining compounds, which have been developed on principally new base and has technological prototypes, make it possible to solve practically all problems of modern industries and by this provides the introduction of the whole row of inorganic fluorides in various branches of industry. 1. fluorides of high purity for microelectronic (PF5, AsF5, S2F10); 2. fluorides of high purity for optical materials; 3. chemical reagents; 4. fluorinating agents for organic chemistry (BiF5, PbF4, TbF4, CoF3, XeF2 …); 5. fluorine-ion conductive materials for solid state batteries and other tasks. The data obtained in this study are discussed together with existing data on classical methods of synthesis and the exchange one in unaqueous solvents.

Raman spectra of the solutions some inorganic fluorides in anhydrous hydrogen fluoride.

Abstract The laser Raman spectra for the solutions KrF 2 (1,5÷7,5), XeF 2 (0.15÷16.5), ClOF 3 (1.8÷9.2), ClOF 2 BF 4 (1.3÷2.8) and ClOF 2 AuF 6 (0.3÷2.8 mole·1 −1 ) in anhydrous HF have been recorded. The spectral study gives an evidence for a strong self-ionisation of ClOF 3 and its salts and for a weak one of XeF 2 in HF (see table): ClOF 3 [ClOF 2 BF 4 ClOF 2 AuF 6 ] = ClOF 2 + + HF 2 − (BF 4 − , AuF 6 − ) XeF 2 = FXe δ+ —[FHF] δ− = XeF 2 ··· FXe δ+ —[FHF] 1 . XeF 2 ClOF 2 HF 2 ClOF 2 BF 4 ClOF 2 AuF 6 ν Δν 1/2 ν Δν 1/2 ν Δν 1/2 ν Δν 1/2 476(47) 47 1333p 10 1334p 8 1334 6.5 539(100) 76 1321p 10 1322p 8.5 1327 7.0 474(37) 52 736p 30 742p 22 748dp 15 510(95) 25 705dp 20 711dp 14 714dp 10 540(100) The existence of ClOF 3 adducts with HF was confirmed by results of thermal analysis with these data the melting point-composition diagram was constructed. Theoretical estimations showed that the value δν 1 2 of ν 1 and ν 2 ClOF 2 + decreases with the increase of solution concentration which is connected with limitation of orientational move of soluble molecules. The orientational time for ν 1 is 1.63 ns (HF 2 − ), 1.31 ns (BF 4 − ) and 1.06 ns (AuF 6 − ), and for ν 2 -three times smaller accordingly the previous values for ν 1 . The data obtained in this study are discussed together with existing data on solid substances.

Modification of polymers by inorganic fluorocontaining oxidants

Abstract The interaction between inorganic fluorocontaining oxidants, in particular, XeF 2 , KrF 2 , ClF 5 in gas phase and polyethylene (plates and foils) in the presence and absence of Lewis fluoroacids, were examined. As a result of polyethylene treatment with fluorinating agents, the surface film, which depending upon the conditions of the process, can contain up to 40% of fluorine, is formed. It was shown that the polyethylene modification is essentially influenced by conditions of the process — the duration of the treatment, fluorinating agent concentration, the temperature of the process, the type and the presence (or absence) of catalyst. The optimum conditions of polyethylene treatment were found out. The polyethylene modified by such method has better chemical resistance, the lower adhesion for some materials. The products of fluorination were identified by the following methods — gravimetry, vibrational spectroscopy (IR and Raman) and ESCA. Some other results of polymers modification, in particular, rubbers in gas phase and polymethylmetacrylate and its copolymers in organic solution will be presented.

Aurum (V) fluorides reactions with water and their thermochemistry.

Abstract The enthalpies of reactions in water of solid Ba(AuF 6 ) 2 ·4KrF 2 and Ba(AuF 6 ) 2 were measured at 298.2 K using an air tight liquid isotermal calorimeter. These enthalpies were used to obtain an alternate set of formation standard enthalpies for these compounds. The analogous to these measurings for AuF 5 and MAuF 6 (M=Na, K, Rb) and also AuF 3 were conducted earlier. Recommended values for ΔH∘ f298 mentioned solid fluorides are: AuF 5 = −413.2±5; NaAuF 6 = −1094.5±6.5; KAuF 6 ≈ −1158.8±6.5; RbAuF 6 ≈ −1145.2±6.5; AuF 3 ≈ −473.4±5 kJ·mole −1 . For ΔH∘ f298 Au(OH) 3 was decided the value −433±6.5 kJ·mole −1 . All compounds were prepared by fluorination of gold in KrF 2 in solutions in HF (Kel-F reactor). Ba(AuF 6 ) 2 ·4Kr F2 was prepared in conditions of a large excess of KrF 2 . It is interesting to note that the reaction AuF 5 in water and aqueous sodium hydroxide (0.05 N) went to precipitation of metallic gold, for example: AuF 5 + 3.475H 2 O = 0.35Au (s) + 0.65Au(OH) 3(s) + 5HF (sol) + 0.76250 2(g) ΔH 298 = −491.9±1.6 kJ·mole −1 The separate measurements gave values of −2442±15 and −3132±15 kJ·mole −1 for ΔH∘ f298 Ba(AuF 6 ) 2 and Ba(AuF 6 ) 2 ·KrF 2 respectively, yielding. Ba(AuF 6 ) 2 + 8H 2 O = BaF 2(s) + 2Au(OH) 3(s) + 10HF (sol) + O 2(g) ΔH 298 = −729±6 kJ·mole −1 Ba(AuF 6 ) 2 ·4KrF 2 + 12H 2 O = BaF 2(s) + 2Au(OH) 3(s) + 18HF (sol) + 30 2(g) + 4Kr (g) ΔH 298 = −1548±10 kJ·mole −1 The reaction enthalpy of the process AuF 3(s) + F 2(g)  AuF 5(s) was estimated. AuF 5 was synthesised by this reaction.