10022-50-1Relevant articles and documents
+/Metal and [XeF5]+/Non-Metal Mixed-Cation Salts of Hexafluoridoantimonate(V)
Mazej, Zoran,Goreshnik, Evgeny
, p. 1453 - 1456 (2015)
New types of [XeF5]+ salts, i.e., NO2XeF5(SbF6)2 and XeF5[Cu(SbF6)3], are derived from reactions between XeF5SbF6 and NO2Sb
Atmospheric Chemistry of FNO and FNO2: Reactions of FNO with O3, O(3P), HO2, and HCl and the Reaction of FNO2 with O3
Wallington, Timothy J.,Schneider, William F.,Szente, Joseph J.,Maricq, M. Matti,Nielsen, Ole John,Sehested, Jens
, p. 984 - 989 (1995)
Upper limits for the rate constants of the following gas phase reactions have been determined at 296 K: k(FNO+O3) -18, k(FNO+O(3P)) -13, k(FNO+HO2) -12, k(FNO+HCl) -18, and k(FNO2+O3) 8
Kinetics and mechanisms of the thermal gas-phase reactions of CF3OF and CF3OOCF3 with NO2
Czarnowski
, p. 83 - 94 (1999)
The kinetics of the reactions of CF3OF and CF3OOCF3 with NO2 have been investigated using a conventional static system. The reaction between CF3OF and NO2 has been studied in a quartz reactor in the temperature range of 313.2-334.2 K, varying the initial pressure of CF3OF between 19.4 and 165.2 Torr and that of NO2 + N2O4 between 18.2 and 179.2 Torr. Some experiments were made in presence of 506.5-600.8 Torr of N2. The total pressure had no influence on the reaction rate. COF2 and FNO2 were identified as reaction products. The expression obtained for the rate constant for the abstraction of fluorine atom from CF3OF by NO2 was: k1 = (1.1±0.2) × 109 exp(-16.4±1 kcal mol-1/ RT) dm3 mol-1 s-1. The reaction of CF3OOCF3 with NO2 has been studied in an aluminum reactor in the temperature range of 474.0-512.5 K, varying the initial pressure of CF3OOCF3 between 24.1 and 202.5 Torr and that of NO2 between 24.7 and 202.7 Torr. Several experiments were made in presence of 399.8-490.5 Torr of N2. The reaction rate was proportional to [CF3OOCF3]1/2. The reaction approached the first order with respect to NO2 at low pressure of NO2. Increasing the pressure of NO2, the ratio of the reaction rates increased more rapidly than the ratio of the corresponding concentrations of NO2. Three products were formed: COF2, FNO and O2. The expression obtained for the rate constant for the abstraction of the fluorine atom from the radical CF3O by NO2 was: k8 = (1.72±0.4) × 109 exp(-10.8±1 kcal mol-1/RT) dm3 mol-1 s-1. The mechanisms for both reactions were postulated. by Oldenbourg Wissenschaftsverlag, Muenchen.
Kinetics of the gas phase reaction OH + NO( + M) → HONO( + M) and the determination of the UV absorption cross sections of HONO
Pagsberg, Palle,Bjergbakke, Erling,Ratajczak, Emil,Sillesen, Alfred
, p. 383 - 390 (1997)
The reaction OH + NO( + M) → HONO( + M) with M = SF6 as a third body has been employed as a clean source for recording the near-ultraviolet absorption spectrum of HONO without interference from other absorbing species. The reaction was initiated by the pulse radiolysis of SF6/H2O/NO mixtures with total pressures in the range 10-1000 mbar at 298 K. The pressure dependence of the rate coefficient was studied by time-resolved UV and IR spectroscopy. By analysis of the fall-off curve we have derived a value for the limiting low pressure rate constant k0/[SF6] = (1.5 ± 0.1) × 10-30 cm6 molecule-2 s-1 at 298 K, using the values of k∞ = (3.3 ± 0.3) × 10-11 cm3 molecule-1 s-1 and Fcent = 0.81 reported by Troe and co-workers. The UV spectrum of HONO was recorded in the range 320-400 nm and an absolute absorption cross section of σ = (5.02 ± 0.76) × 10-19 cm2 molecule-1 has been determined for the strongest band of HONO located at 354.2 nm. Differential absorption cross sections to be used for field measurements of HONO were also investigated.
14N Quadrupole Coupling Constants and 14N and 19F Spin-Rotation Coupling Constants of Nitrosyl Fluoride, FNO, and Nitryl Fluoride, FNO2
Styger, Christian,Gatehouse, Bethany,Heineking, Nils,Jaeger, Wolfgang,Gerry, Michael C. L.
, p. 1899 - 1902 (1993)
High-resolution pure rotational spectra of nitrosyl fluoride, FNO, and nitryl fluoride, FNO2, have been measured using a cavity pulsed microwave Fourier-transform spectrometer.The samples were prepared using a pulsed electric discharge through precursor substances, with the discharge apparatus mounted as part of the pulsed nozzle of the spectrometer.Nuclear quadrupole and magnetic hyperfine structures due to 14N and 19F have been resolved for both molecules, and precise values for the nuclear quadrupole and spin-rotation coupling constants have been obtained.The 14N quadrupole coupling constants of FNO2 have been rationalized in terms of a ?-withdrawal of electron density from NO2 towards F.This view is corroborated by the magnetic shielding estimated from the F spin-rotation constants.
XeOF3-, an example of an AX3YE2 valence shell electron pair repulsion arrangement; Syntheses and structural characterizations of [M][XeOF3] (M = Cs, N(CH3) 4)
Brock, David S.,Mercier, Helene P. A.,Schrobilgen, Gary J.
, p. 10935 - 10943 (2010/09/16)
The XeOF3- anion has been synthesized as its Cs + and N(CH3)4+ salts and structurally characterized in the solid state by low-temperature Raman spectroscopy and quantum-chemical calculations. Vibrational frequency assignments for [Cs][XeOF3] and [N(CH3) 4][XeOF3] were aided by 18O enrichment. The calculated anion geometry is based on a square planar AX3YE 2 valence-shell electron-pair repulsion arrangement with the longest Xe-F bond trans to the oxygen atom. The F-Xe-F angle is bent away from the oxygen atom to accommodate the greater spatial requirement of the oxygen double bond domain. The experimental vibrational frequencies and trends in their isotopic shifts are reproduced by the calculated gas-phase frequencies at several levels of theory. The XeOF3- anion of the Cs + salt is fluorine-bridged in the solid state, whereas the anion of the N(CH3)4+ salt has been shown to best approximate the gas-phase anion. Although [Cs][XeOF3] and [N(CH 3)4][XeOF3] are shock-sensitive explosives, the decomposition pathways for the anions have been inferred from their decomposition products at 20°C. The latter consist of XeF2, [Cs][XeO2F3], and [N(CH3)4][F]. Enthalpies and Gibbs free energies of reaction obtained from Born-Fajans-Haber thermochemical cycles support the proposed decomposition pathways and show that both disproportionation to XeF2, [Cs][XeO2F3], and CsF and reduction to XeF2, CsF, and O2 are favorable for [Cs][XeOF3], while only reduction to XeF2 accompanied by [N(CH3)4][F] and O2 formation are favorable for [N(CH3)4][XeOF3]. In all cases, the decomposition pathways are dominated by the lattice enthalpies of the products.
Kinetic and mechanistic studies of the reactions of CF3O radicals with NO and NO2
Fockenberg,Somnitz,Bednarek,Zellner
, p. 1411 - 1420 (2007/10/03)
The reactions of CF3O radicals with (1) NO and (2) NO2 were-studied using two different experimental techniques. A laser photolysis/LIF detection method was applied for measuring the rate constants as a function of temperature (T=222-302 K) and total pressure (ptot = 7-107 mbar). Whereas the reaction with (1) NO was found to be independent of temperature and pressure with k1 = (4.5±1.2)×10-11 cm3 s-1, the reaction with (2) NO2 was found to be dependent on both of these variables. The temperature dependence of k2 in the high pressure limit can be given by the expression k2, ∞ (T)=(8±5)×10-13 exp ((863±194) K/T) cm3 s-1. The product distributions of the two reactions were determined in separate experiments using steady-state photolysis combined with FTIR spectroscopy. For reaction (1) only CF2O was found as a reaction product with a yield of 0.93±0.10, independent of temperature. For reaction (2) several products (CF3ONO2, CF2O, FNO2) were identified, the overall yield, however, is dominated (≥90%) by the recombination product CF3ONO2. A theoretical analysis of the detailed mechanisms of both reactions was made by performing ab initio energy and geometry predictions in combination with RRKM calculations. Both reactions were found to proceed via an initial addition mechanism involving the CF3ONOx (x=1, 2) intermediate and a four-center transition state. A direct abstraction of an F atom by NO or NO2 can be excluded. WILEY-VCH Verlag GmbH, 1997.
Fluorine-oxygen exchange reactions in IF5, IF7, and IF5O
Christe, Karl O.,Wilson, William W.,Wilson, Richard D.
, p. 904 - 908 (2008/10/08)
When reacted with alkali-metal nitrates, IF5 readily exchanges two fluorine ligands for a doubly bonded oxygen atom. In all cases MIF4O salts (M = Li, K, Cs) and FNO2 are formed as the primary products. The FNO2 byproduct undergoes a fast secondary reaction with MNO3 to yield equimolar amounts of N2O5 and MF. The N2O5 decomposes to N2O4 and 0.5 mol of O2, while the MF, depending on the nature of M, does or does not undergo complexation with the excess of IF5. Pure MIF4O salts, free of MF or MF·nIF5 byproducts, were prepared from MF, I2O5, and IF5 in either CH3CN or IF5 as a solvent. The new compounds LiIF4O, NaIF4O, RbIF4O, and NOIF4O were characterized by vibrational spectroscopy. It was also shown that, contrary to a previous report, FNO2 does not form a stable adduct with IF5 at temperatures as low as -78°C. An excess of IF7 reacts with MNO3 (M = Li, Na) to give MF, FNO2, IF5, and 0.5 mol of O2, but surprisingly no IF5O. With CsNO3, the reaction products are analogous, except for the CsF reacting with both the IF5 product and the excess of IF7 to give CsIF6·2IF5 and CsIF8, respectively. When in the IF7 reaction an excess of LiNO3, is used, the IF5 product undergoes further reaction with LiNO3, as described above. The IF5O molecule was found to be rather unreactive. It does not react with either LiF or CsF at 25 or 60°C or with LiNO3 or CsNO3 at 25°C. At 60°C with LiNO3, it slowly loses oxygen, with the IF5 product reacting to yield LiIF4O, as described above.
Reactions of chlorine fluorides and oxyfluorides with the nitrate anion and alkali-metal fluoride catalyzed decomposition of ClF5
Christe, Karl O.,Wilson, William W.,Wilson, Richard D.
, p. 675 - 677 (2008/10/08)
The binary chlorine fluorides ClF5, ClF3, and ClF, when used in an excess, all undergo facile fluorine-oxygen exchange reactions with the nitrate anion, forming FClO2, unstable FClO, and ClONO2, respectively, as the primary products. Whereas FClO3 does not react with LiNO3 at temperatures as high as 75°C, FClO2 readily reacts with either LiNO3 or N2O5 to give ClONO2 and O2 in high yield, probably via the formation of an unstable O2ClONO2 intermediate. With an excess of ClF, chlorine nitrate undergoes a slow reaction to give FNO2 and Cl2O as the primary products, followed by Cl2O reacting with ClF to give Cl2, ClF, and FClO2. The alkali-metal fluorides CsF, RbF, and KF catalyze the decomposition of ClF5 to ClF3 and F2, which can result in the generation of substantial F2 pressures at temperatures as low as 25°C.
New syntheses and properties of XeO2F2, Cs+XeO2F3-, and NO2+[XeO2F3·nXeO 2F2]-
Christe, Karl O.,Wilson, William W.
, p. 3763 - 3768 (2008/10/08)
Alkali-metal nitrates and N2O5 are useful reagents for the stepwise replacement of two fluorine atoms by one oxygen atom in xenon fluorides or oxyfluorides. Thus, the reaction of an excess of XeF6 with CsNO3 yields XeOF4, FNO2, and CsXeF7 in high yield. With CsNO3 in excess, the primary products are CsXeOF5 and FNO2, and after longer reaction times some CsXeO2F3 is also formed. The reaction of CsNO3 with an excess of XeOF4 produces FNO2 and XeO2F2 in quantitative yield with a mixture of CsF and CsXeOF5 as the byproducts. Recrystallization of this CsF-CsXeOF5-XeO2F2 mixture from anhydrous HF provides a convenient synthesis for CsXeO2F3. The reaction of N2O5 with an excess of XeOF4 results in XeO2F2 and FNO2, thus providing a new safe synthesis for XeO2F2. Vibrational spectra of liquid, solid, and Ar-matrix-isolated XeO2F2 are reported. With FNO2, xenon dioxide difluoride forms an unstable NO2+[XeO2F3·nXeO 2F2]- adduct, which was characterized by Raman spectroscopy. The vibrational spectra of CsXeO2F3 were recorded and assigned. It is shown that the two oxygen atoms in XeO2F3- are cis and not trans to each other and that the Raman spectrum previously attributed to Cs+XeO2F3- is due to a Cs+[XeO2F3·nXeF2]- adduct.
