Thermodynamics of allotropic modifications of carbon: Synthetic diamond, graphite, fullerene C60 and carbyne

Tsvetkova, L. Ya.; Zhogova, K. B.

doi:10.1016/s0040-6031(97)00148-2

Cited by 16 publications

(8 citation statements)

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“…In this connection, it was of interest to compare the temperature dependences of the heat capacities of the nanostructures under study with those of graphite 27, 28 and diamond 26,28 at Т < 100 K (see Fig. 3).…”

Section: Resultsmentioning

confidence: 99%

“…The zero point entropies of the substances under study were taken equal to zero and the absolute entropies of fullerite C 60 , graphite, and dia mond were taken from Ref. 28. All calculations were car ried out per mole of C 60 (M = 720.66 g mol -1 ).…”

Section: Resultsmentioning

confidence: 99%

“…Low temperature heat capacities of diamond26 (1), graph ite like nanostructures I (2) and II (3), graphite 27 (4), and sam ple III28 (5) (calculated per mole of the C atoms).…”

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Thermodynamic properties of graphite-like nanostructures prepared by thermobaric treatment of fullerite C60

et al. 2008

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Temperature dependences of the heat capacities of disordered graphite like nanostructures prepared by the thermobaric treatment of fullerite C 60 (p = 2 and 8 GPa, T = 1373 K) were measured in the temperature ranges from 7 to 360 K in an adiabatic vacuum calorimeter and from 330 to 650 K in a differential scanning calorimeter. At Т < 50 K, the dependences obtained were analyzed using the Debye theory of the heat capacity of solids and its multifractal version. The fractal dimensions D were determined and some conclusions on the heterodynamic charac ter of the structures studied were made. The thermodynamic functions С р°( Т), Н°(Т) -Н°(0), S°(T) -S°(0), and G°(T) -H°(0) were calculated in the temperature range from Т → 0 to 610 (650) K. The thermodynamic properties of the graphite like nanostructures studied and some carbon allotropes were compared. The standard entropies of formation Δ f S° of the graphite nanostructures studied and diamond were calculated along with the standard entropies of the reactions of their synthesis from the face centered cubic phase of fullerite C 60 and their inter conversions at Т = 298.15 K.There is considerable literature on the studies of fullerenes, their derivatives, and materials based on them. 1-8 The thermobaric treatment of fullerite C 60 followed by abrupt pressure drop from several GPa to р = 0.1 MPa and lowering the temperature to 298.15 K pro duces new carbon materials. 4-12 Under these conditions, the systems are thermodynamically metastable but kineti cally stable. In some cases, the thermobaric treatment of the face centered cubic (fcc) phase of fullerite C 60 causes breakdown of the molecular cage and formation of di sordered nanostructures 4,8,11-13 containing the sp 2 and sp 3 hybridized carbon atoms. These structures are similar in physicochemical properties to graphite and diamond. The fraction of the sp 3 hybridized C atoms in the fi nal product significantly increases under pressures of 8-10 GPa. 14 Interest in carbon materials is due to their unique properties, e.g., superhardness, 4,8,15 superconductivity, 16,17 high plasticity, 4,15 and controlled anisotropy of elastic properties. 12 There is a demand for studies of the thermo dynamic properties of carbon materials and optimization of technology of their production.The purpose of this work is to carry out a calorimetric study of the temperature dependences of the heat capacity of the graphite like nanostructures (GNS) produced by the thermobaric treatment of fullerite C 60 in the tempera ture interval from 7 to 610-650 K; to analyze these de pendences at T < 50 K in the framework of the Debye theory of the heat capacity of solids and its multifractal version; to calculate the standard thermodynamic func tions in the temperature range from Т → 0 to 610-650 K; to compare the standard thermodynamic properties of the GNS and some carbon allotropes; and to establish how their physicochemical properties depend on the structure. ExperimentalDoubly sublimed, finely crystalline powdered fullerite C 60 (grain size ~10...

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Thermodynamic properties of graphite-like nanostructures prepared by thermobaric treatment of fullerite C60

et al. 2008

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“…Structure and property relationship of the cationic conjugated polyelectrolytes, which are a new class of conjugated polymers, and conjugated polyelectrolytes with applications in many substantially different technologies is reported by Sheng et al [395]. Despite considerable interest in these species, there are few determinations of the enthalpy of formation of any conjugated polymer-indeed, only polyacetylene [396], polyaniline [397], carbyne [398], and poly(phenylacetylene) (and some copolymers thereof) [399] have seemingly been studied by experimentalists.…”

Section: Issuementioning

confidence: 99%

Interplay of thermochemistry and Structural Chemistry, the journal (volume 18, 2007) and the discipline

Ponikvar

Liebman

2008

Struct Chem

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In this study, we relate the contents of the journal Structural Chemistry for the calendar year 2007 and thermochemistry. The year's articles were briefly summarized and a thermochemical comment written to supplement them. Frequently questions were asked and future research was suggested.Keywords Structural Chemistry Á Thermochemistry Á Thermodynamics Á Enthalpy of formation Á Enthalpy of phase change Á Enthalpy of reaction As practiced disciplines, structural chemistry and thermochemistry are very often unrelated. In this study, these disciplines are linked as relations are explicitly made using the contents of the journal Structural Chemistry (Vol. 18) for the calendar year 2007 as a scaffold for our analysis, for our selected articles in the discipline of structural chemistry. These studies have been reviewed by us, where we give them a thermochemical flavor. While this commentary is most generally written in terms of brief summaries of literature papers involving enthalpies of formation and/or reaction, not uncommonly we raise questions and even suggest possible future research. We are not, however, going to give a thermochemical slant on book reviews, honorary dedications, and obituaries although these works will be cited in our text.As such, this article is a sequel to our earlier related reviews of Structural Chemistry for the calendar years 2000 through 2004 [1-5]. Reviews for 2005 and 2006 are currently being prepared. Issue 1In the first article in the first issue of Structural Chemistry for 2007, Hargittai [6] asserted that while research is currently usually carried out in big groups, the most important ideas, observations and discoveries still belong to individuals who have to bring down dogmas or open entirely new areas in science. This may bring solace to the thermochemical community in which research groups are generally small, and the number of new practitioners sadly few.In the past decade, the crystal engineering of multidimensional arrays and networks containing metal ions has achieved considerable progress because of the increased interest in the potential utility of these compounds as zeolite-like materials [7-11], catalysts [12], or magnetic materials [13][14][15]. The thermochemistry of these species is complicated by their inherent complexity: however, estimation approaches of their key thermochemical quantities are increasingly reliable [16]. In the second article of this issue, by Wang et al. [17], the versatility of malonate dianion as a ligand for the construction of extended networks with different topologies dependent on the coordination geometry of the metal ion was discussed. The synthesis and structure of a novel malonate-bridged copper(II) compound in which copper(II) ions have two different coordination environments in a novel three-dimensional (3D) network was described. Metal malonates have been studied from a

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“…For example, in the case of carbon, measurements with an adiabatic calorimeter by Lebedev et al show that at room temperature there is a difference of 30% between the specific heats of diamond and graphite. 3 Therefore, in order to test the validity of the rule of mixtures for complex clay based materials, measurements are necessary.…”

Section: Introductionmentioning

confidence: 99%

Effect of dehydroxylation on the specific heat of simple clay mixtures

Michot

Smith

Degot

et al. 2011

Journal of the European Ceramic Society

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Thermodynamics of allotropic modifications of carbon: Synthetic diamond, graphite, fullerene C60 and carbyne

Cited by 16 publications

References 6 publications

Thermodynamic properties of graphite-like nanostructures prepared by thermobaric treatment of fullerite C60

Thermodynamic properties of graphite-like nanostructures prepared by thermobaric treatment of fullerite C60

Interplay of thermochemistry and Structural Chemistry, the journal (volume 18, 2007) and the discipline

Effect of dehydroxylation on the specific heat of simple clay mixtures

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