NIST-JANAF Thermochemical Tables for Oxygen Fluorides

Abstract

The thermodynamic and spectroscopic properties of the oxygen fluoride species have been reviewed. Recommended thermochemical tables are given for five gaseous oxygen fluorides: OF, OFO, FOO, FOF, and O2F2. Sufficient information is not available to generate thermochemical tables for any condensed phase species. Annotated bibliographies (over 600 references) are provided for all neutral oxygen fluorides which have been reported in the literature. There are needs for additional experimental and theoretical data to reduce the uncertainties in the recommended values for these five species. Of all the species mentioned in the literature, many have not been isolated and characterized. In fact, some do not exist. Throughout this paper, uncertainties attached to recommended values correspond to the uncertainty interval, equal to twice the standard deviation of the mean.

A Computational Study of the Thermochemistry of Bromine- and Iodine-Containing Methanes and Methyl Radicals

“…These were obtained from the computed enthalpies of formation of methane and the corresponding methyl radical and the experimental value for an H atom (218.0 kJ mol -1 ). 8 The data reveal a consistent trend of C-H bond weakening with increasing Br or I substitution. Figure 3 indicates that the number of halogen atoms is more important than their nature, and the trend line drawn corresponds to a weakening of 18.3 kJ mol -1 per halogen atom.…”

“…This molecule is important because it anchors the contrasting interpolation schemes of Papina et al 50 and Bickerton et al, 14 where the latter authors use 83.9( 3.4 kJ mol -1 . The JANAF tables 8 give an even lower value of 50.2 kJ mol -1 , which must be in error. Our calculated value lies between contradictory earlier calculations of 119.2 ( 4.2 and 105.6 ( 3.3 kJ mol -1 , where presumably at least one set of error limits has been underestimated.…”

“…Computed bond lengths and angles in the halomethanes and halomethyl radicals are presented in Table 1, together with available experimental data on the former species. 8,9,37 To the authors' knowledge, no geometries have been reported for the radicals to date. The agreement of calculated geometric parameters with experiment is good, with bond lengths accurate to within 0.01-0.03 Å (computed lengths are higher) and bond angles to within 1°.…”

“…While there is considerable thermochemical information available [6][7][8] for the lighter halogens, experimental data are sparse for bromine-and especially iodine-containing species. There are also some extraordinarily large discrepancies in the literature, which in the case of the enthalpy of formation of CI 4 exceeds 200 kJ mol -1 .…”

Quantitative Chemically Specific Coherent Diffractive Imaging of Reactions at Buried Interfaces with Few Nanometer Precision

“…2e,f) and in the simple model for the coated sample. Adding an Al 2 O 3 layer on top of the Al layer could not resolve this contrast inversion, nor could assuming that the Al scavenged O from the copper oxides to form Al 2 O 3 at the interface, which is an energetically favorable reaction since 2Al + 3CuO → Al 2 O 3 + 3Cu corresponds to ∆ f H • = −1207.52 kJ/mol [41].…”