The Heats of Formation and Polymerization of Carbon Suboxide

Kybett, Brian D.; Johnson, Gerald K.; Barker, C. K.; Margrave, John L.

doi:10.1021/j100894a060

Cited by 32 publications

(13 citation statements)

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“…From Ref. [15], we find a gas phase enthalpy of formation of -97.8 ± 1.8 kJ/mol and a liquid phase enthalpy of formation of -121.5 ± 1.0 kJ/mol. Consider reaction 4 for which the reaction is exothermic by 30.8 kJ/mol.…”

mentioning

confidence: 81%

Paradigms and paradoxes: organic thermochemistry without hydrogen: carbon oxides and nitrides

Slayden

Liebman

2008

Struct Chem

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All organic compounds contain carbon. Most contain hydrogen. This brief study discusses the enthalpy of formation of a collection of organic compounds containing only oxygen or nitrogen accompanying the carbon.By definition, organic chemistry is the chemistry of carboncontaining compounds. Almost always, in practice organic chemistry is also the chemistry of compounds containing hydrogen. Relatedly, organic thermochemistry discusses the thermochemistry of carbon-, and most often, hydrogen-, containing species. There are several thousand organic species for which the enthalpies of formation is known. In the current note we discuss the enthalpies of formation of those species that lack hydrogen, in particular, carbon oxides and carbon nitrides but not halocarbons. The current study will be limited to those species for which these data are found from experiment, whether or not the species be isolable. We will also limit our attention to neutral species and so ignore all ions such as the commonplace CN -and rather exotic CN + . We proceed first through the oxides and then the nitrides of carbon. Within each group, the compounds are discussed in order of increasing number of carbons, and then by increasing number of oxygens or nitrogens. All unreferenced enthalpies of formation in the current study are taken from Ref.[1] and may tacitly be assumed to refer to gaseous species at 298 K and 1 atm unless otherwise said.While there are a respectable number of species containing only carbon and oxygen, there are only three isolable compounds for which enthalpy of formation data are available: carbon monoxide (CO), carbon dioxide (CO 2 ) and propadienedione (C 3 O 2 ), the so-called carbon suboxide. Not limiting our species of interest by grounds of isolability allows us to consider other oxides of carbon, CO 3 , C 2 O, and C 3 O.Enthalpies of formation of CO and CO 2 are found from numerous sources. We choose the values -110.525 and -393.509 kJ/mol [2]. These values are well-established, the latter providing a benchmark value for the enthalpies of formation and combustion of nearly all organic compounds. Perhaps the only thermochemical observation of consequence we will make in this study relates to their carbon-oxygen bond energies. The ratio of the C-O bond energy in CO 2 to that of (the mean) value for CO is very nearly the same as the ratio for the Si-O bond energies in SiO 2 and gaseous SiO despite the fact that CO 2 is ''naturally'' a gas while SiO 2 is ''naturally'' a solid. Perhaps this is not so strange: this near constant ratio in the gas phase for some other pairs of species containing group 14-16 atoms was first pointed out in Ref. [3], and extended by consideration of experimentally unexplored neutrals [4] as well as valence isoelectronic pairs of cations [5], anions [5], and some hydrogen-containing pentatomics as well [6]. Summarizing, for 10 valence electron AB and 16 valence electron AB 2 , we findThis is a comfortably simple approximation for bond energies and a good example of how the investigation of

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mentioning

confidence: 81%

Paradigms and paradoxes: organic thermochemistry without hydrogen: carbon oxides and nitrides

Slayden

Liebman

2008

Struct Chem

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“…The major peaks in the IR spectrum of the C 3 O 2 residue (with possible functional group assignments based on their peak wavenumber) fall at 2156 (CO groups), 1781 (C= =O bonds), 1617 (C= =C bonds), and 1388/1361 cm −1 (O= =C-O groups). Weak absorption features also appear in the 3600-2850 cm −1 region, indicative of cyclic carbon structures; these features may imply the presence of C 3 O 2 thermal polymer, as its structure is likely a polycyclic unsaturated lactone as described in Kybett et al (1965) and the references therein. The residue of irradiated CO has a much weaker feature near 2160 cm −1 , and strong peaks at 1712, 1614, 1449, 1288, and 1031 cm −1 .…”

Section: Figmentioning

confidence: 92%

Carbon Suboxide in Astrophysical Ice Analogs

Gerakines

Moore

2001

Icarus

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“…Three main peaks are detected at 3303, 2155, and 1785 cm −1 , and a fourth at 1762 cm −1 blended with the 1785 cm −1 band. The broad peak at 3303 cm −1 could be related to carbon suboxide polymers (Kybett et al 1965; see also discussion in Gerakines & Moore 2001). The broad peak at 2155 cm −1 indicative of aC=C=O bond overlaps with the new C n O 2 species detected in the infrared spectra that survive up to high temperature during the warm-up (see Figure 4).…”

Section: Products Of the Irradiationmentioning

confidence: 93%

Chemical Evolution of a Co Ice Induced by Soft X-Rays

Ciaravella

Chen

Cecchi‐Pestellini

et al. 2016

ApJ

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We irradiated a pure carbon monoxide ice with soft X-rays of energies up to 1.2 keV. The experiments were performed using the spherical grating monochromator beamline at the National Synchrotron Radiation Research Center in Taiwan, exploiting both monochromatic (at 0.3 and 0.55 keV) and broader energy (0.25-1.2 keV) fluxes. The infrared spectra of the irradiated ices showed the formation of a number of products such as polycarbon monoand dioxides C n O m , and chains containing up to 10 carbon atoms. While a gentle increase in the energy absorbed by the ice sample is reflected by an increase in the column densities of newly born species, such correlation breaks down at very high fluxes. In this regime the production yield falls down sharply by about a factor of 100. The refractory residue obtained in the broad energy irradiation is a "compromise" between those obtained with proton irradiation of C 3 O 2 and CO ices in previous experiments. Finally, we discuss the possible implications for space chemistry

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The Heats of Formation and Polymerization of Carbon Suboxide

Cited by 32 publications

References 0 publications

Paradigms and paradoxes: organic thermochemistry without hydrogen: carbon oxides and nitrides

Paradigms and paradoxes: organic thermochemistry without hydrogen: carbon oxides and nitrides

Carbon Suboxide in Astrophysical Ice Analogs

Chemical Evolution of a Co Ice Induced by Soft X-Rays

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