2551-62-4Relevant academic research and scientific papers
Refinement of the autoneutralization lifetimes of short lived states of SF6-
Appelhans, A. D.,Delmore, J. E.
, p. 5561 - 5570 (1988)
Previous measurements of the autoneutralization lifetime of SF6- indicated there are multiple states (lifetimes) and that the distribution of states is controlled, at least in part, by the temperature of the SF6 molecules prior to electron capture.These measurements indicated the existence of a short lived state with a lifetime of the order of 2 μs.The experimental apparatus has been revised to confirm the existence of the short lived state and provide a more accurate measurement of the lifetime.
The standard molar enthalpy of formation at 298.15 K of VS1.043 by combustion calorimetry in fluorine
Lewis, Brett M.,O'Hare, P. A. G.,Mukdeeprom, Pannee,Edwards, Jimmie G.
, p. 1325 - 1331 (1987)
The standard molar enthalpy of formation ΔfH0m of VS1.043 has been determined by fluorine-combustion calorimetry.The results obtained, -(230.3+/-2.2)kJ*mol-1 at 298.15 K and p0 = 101.325 kP
Standard molar enthalpy of formation at 298.15 K of the β-modification of molybdenum ditelluride
O'Hare, P. A. G.,Hope, G. A.
, p. 701 - 708 (1989)
Fluorine-combustion calorimetry of a high-purity sample of molybdenum ditelluride has yielded the standard molar enthalpy of formation: ΔfH0m(MoTe2, cr, β, 298.15 K) = -(84.2 +/- 4.6) kJ * mol-1.At 298.15 K, the enthalpy of the hypothetical β-to-α transition in MoTe2 is approximately -6 kJ * mol-1.The present result for ΔfH0m(MoTe2) has been combined with literature values for the decomposition pressures of MoTe2 to yield ΔfH0m(Mo3Te4, cr, 298.15 K) = -(185 +/- 10) kJ * mol-1.Our previously published ΔfH0m(TeF6) (Trans.Faraday Soc. 1966, 62, 558) has been revised slightly to -(1371.8 +/- 1.8) kJ * mol-1.
The standard molar enthalpy of formation at 298.15 K of S2N+AsF6- by fluorine combustion calorimetry
O'Hare, P. A. G.,Awere, Edward G.,Parsons, Simon,Passmore, Jack
, p. 153 - 158 (1989)
The energy of combustion of S2N+AsF6- in high-pressure fluorine has been measured calorimetrically.The only fluorine-containing gases formed in the combustion were SF6 and AsF5; both NF3 and AsF3 were sought, but not detected.The standard molar
F5SN(H)Xe+; a rare example of xenon bonded to sp 3-hybridized nitrogen; synthesis and structural characterization of [F5SN(H)Xe][AsF6]
Smith, Gregory L.,Mercier, Helene P. A.,Schrobilgen, Gary J.
, p. 4173 - 4184 (2009/02/01)
The salt [F5SN(H)Xe][AsF6] has been synthesized by the reaction of [F5SNH3][AsF6] with XeF 2 in anhydrous HF (aHF) and BrF5 solvents and by solvolysis of [F3S=NXeF][AsF6] in aHF. Both F 5SN(H)Xe+ and F5SNH3+ have been characterized by 129Xe, 19F, and 1H NMR spectroscopy in aHF (-20°C) and BrF5 (supercooled to -70°C). The yellow [F5SN(H)Xe][AsF6] salt was crystallized from aHF at -20°C and characterized by Raman spectroscopy at -45°C and by single-crystal X-ray diffraction at -173°C. The Xe-N bond length (2.069(4) A) of the F5SN(H)Xe+ cation is among the shortest Xe-N bonds presently known. The cation interacts with the AsF6- anion by means of a Xe...F-As bridge in which the Xe...F distance (2.634(3) A) is significantly less than the sum of the Xe and F van der Waals radii (3.63 A) and the AsF6 - anion is significantly distorted from Oh symmetry. The 19F and 129Xe NMR spectra established that the [F 5SN(H)Xe][AsF6] ion pair is dissociated in aHF and BrF5 solvents. The F5SN(H)Xe+ cation decomposes by HF solvolysis to F5SNH3+ and XeF 2, followed by solvolysis of F5SNH3+ to SF6 and NH4+. A minor decomposition channel leads to small quantities of F5SNF2. The colorless salt, [F5SNH3][AsF6], was synthesized by the HF solvolysis of F3S≡NAsF5 and was crystallized from aHF at -35°C. The salt was characterized by Raman spectroscopy at -160°C, and its unit cell parameters were determined by low-temperature X-ray diffraction. Electronic structure calculations using MP2 and DFT methods were used to calculate the gas-phase geometries, charges, bond orders, and valencies as well as the vibrational frequencies of F5SNH 3+ and F5SN(H)Xe+ and to aid in the assignment of their experimental vibrational frequencies. In addition to F 5TeN(H)Xe+, the F5SN(H)Xe+ cation provides the only other example of xenon bonded to an sp3-hybridized nitrogen center that has been synthesized and structurally characterized. These cations represent the strongest Xe-N bonds that are presently known.
Kinetics of sulfur oxide, sulfur fluoride, and sulfur oxyfluoride anions with atomic species at 298 and 500 K
Midey, Anthony J.,Viggian
, p. 1852 - 1859 (2008/10/09)
The rate constants and product-ion branching ratios for the reactions of sulfur dioxide (SO2-), sulfur fluoride (SF n-), and sulfur oxyfluoride anions (SOxF y-) with H, H2, N, N2, NO, and O have been measured in a selected-ion flow tube (SIFT). H atoms were generated through a microwave discharge on a H2/He mixture, whereas O atoms were created via N atoms titrated with NO, where the N had been created by a microwave discharge on N2. None of the ions reacted with H 2, N2 or NO; thus, the rate constants are -12 cm3 s-1. SOxFy - ions react with H by only fluorine-atom abstraction to form HF at 298 and 500 K. Successive F-atom removal does not occur at either temperature, and the rate constants show no temperature dependence over this limited range. SO2- and F- undergo associative detachment with H to form a neutral molecule and an electron. Theoretical calculations of the structures and energetics of HSO2- isomers were performed and showed that structural differences between the ionic and neutral HSO 2 species can account for at least part of the reactivity limitations in the SO2- + H reaction. All of the SOxF y- ions react with O; however, only SO2 - reacts with both N and O. SOxFy- reactions with N (SO2- excluded) have a rate constant limit of -11 cm3 s-1. The rate constants for the SOxFy- reactions with H and O are ≤25% of the collision rate constant, as seen previously in the reactions of these ions with O3, consistent with a kinetic bottleneck limiting the reactivity. The only exceptions are the reactions of SO2 - with N and O, which are much more efficient. Three pathways were observed with O atoms: F-atom exchange in the reactant ion, F- exchange in the reactant ion, and charge transfer to the O atom. No associative detachment was observed in the N- and O-atom reactions.
Pentafluoronitrosulfane, SF5NO2
Lu, Norman,Thrasher, Joseph S.,Von Ahsen, Stefan,Willner, Helge,Hnyk, Drahomir,Oberhammer, Heinz
, p. 1783 - 1788 (2008/10/09)
The synthesis of pentafluoronitrosulfane, SF5NO2, is accomplished either by reacting N(SF5)3 with NO 2 or by the photolysis of a SF5Br/NO2 mixture using diazo lamps. The product is purified by treatment with CsF and repeated trap-to-trap condensation. The solid compound melts at -78°C, and the extrapolated boiling point is 9°C. SF5NO2 is characterized by 19F, 15N NMR, IR, Raman, and UV spectroscopy as well as by mass spectrometry. The molecular structure of SF 5NO2 is determined by gas electron diffraction. The molecule possesses C2v symmetry with the NO2 group staggering the equatorial S-F bonds and an extremely long 1.903(7) A S-N bond. Calculated bond enthalpies depend strongly on the computational method: 159 (MP2/6-311G++(3df)) and 87 kJ mol-1 (B3LYP/6-311++G-(3df)). The experimental geometry and vibrational spectrum are reproduced reasonably well by quantum chemical calculations.
HONO solubility and heterogeneous reactivity on sulfuric acid surfaces
Longfellow,Imamura,Ravishankara,Hanson
, p. 3323 - 3332 (2007/10/03)
The solubility of HONO in various wt% sulfuric acid solutions was measured. HONO becomes increasingly more soluble in high acid wt% solutions, probably resulting from the protonation of HONO to give H2ONO+, followed by dissociation and association to give NO+HSO4- (nitrosyl sulfuric acid). The reaction of HONO with HCl on 50, 60, 67, and 70 wt% sulfuric acid solutions was also studied. The measured uptake coefficients could not be explained simply by the occurrence of a bulk phase reaction, and a surface effect is found to contribute to the uptake. The reaction of HONO with HCl was measured on sulfuric acid particles, and a small reacto-diffusive length further supports a surface reaction. From extrapolating our measured uptake values to stratospheric conditions, the formation of ClNO from the heterogeneous reaction of HONO and HCl is concluded to be an insignificant process in the volcanically unperturbed stratosphere.
Low temperature fluorination of some non-metals and non-metal compounds with fluorine
Padma, D K,Kalbandkeri, R G,Suresh, B S,Bhat, V Subrahmanya
, p. 172 - 176 (2007/10/02)
Low temperature fluorination with elemental fluorine of elemental phosphorus, sulphur, silicon, amorphous carbon and phosphorus trichloride, phosphorus pentoxide, triphenylphosphine, hexafluorodisilane, hexachlorodisilane, hexabromodisilane, tetrasulphur tetranitride, sulphur dioxide, thionyl chloride and sulphuryl chloride has been carried out in freon-11 medium.The corresponding fluoro compounds have been isolated in near quanititative yields, purified by low temperature fractional condensation and characterised by IR spectroscopy and elemental analysis.
