The suggested approach "Selected set of samples + selected set of analytical tools" occurred quite efficient when applying to sp 2 amorphous carbons, thus providing a transformation of 'amorphous' representation of the issue, based on particulars, into a 'crystalline' one based on a limited set of fixed commonalities. The slogan first part implies a set of different-origin solid samples. The second part concerns analytical tools, the most suitable to achieve the goal. The parts combining means the application of each tool to the whole set of samples. In the current study, two natural sp 2 amorphous carbons, namely, shungite carbon and antraxolite, as well as two engineered products -carbon blacks CB632 and CB624, all of the four bodies belonging to the elitist highest-carbon-content sp 2 species, were subjected to analytical study by using modern structural and compositional analytical techniques. The approach has allowed disclosing the following steady points that are common to the whole class of this carbon allotrope and that may lay the foundation of consolidate, more 'crystalline' representation of what are sp 2 amorphous carbons:1. sp 2 Amorphous carbons are products of particular chemical reactions related to their basic structural units. Further macroscopic agglomeration of the latter plays a subsidiary role. 2. The units represent framed graphene molecules of 1-2 nm and 1-x*10 (x=1-3) nm in size in the case of natural and engineered products, respectively.3. Framing of graphene molecules, predominantly incomplete with respect to the number of vacant places, concerns only edge atoms and is implemented by the related chemical additives, such as hydrogen, oxygen, nitrogen, sulfur and halogens which are attached to the carbon core via chemical bonding. 4. The molecules small size provides a countable number of newly formed chemical bonds.INS and XPS allow attributing the bonds to chemical compositions restricted by number while QCh ensures reliable support. 5. Temperature and pressure as well as physical state and chemical content of surrounding media are the main factors governing geochemistry and technical chemistry of carbon products. 6. Graphene molecules, laying the foundation of sp 2 amorphous carbons, are strongly radicalized due to which the latter acquire a new facet in the space of their properties, being the largest repository of stable radicals.

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The response of a nanographene sheet to external stresses was considered in terms of a mechanochemical reaction. The quantum chemical realization of the approach was based on the coordinate-of-reaction concept for the purpose of introducing a mechanochemical internal coordinate (MIC) that specifies a deformational mode. The related force of response is calculated as the energy gradient along the MIC, while the atomic configuration is optimized over all of the other coordinates under the MIC constant-pitch elongation. The approach is applied to the benzene molecule and (5,5) nanographene. A drastic anisotropy in the microscopic behavior of both objects under elongation along a MIC was observed when the MIC was oriented either along or normally to the C-C bond chain. Both the anisotropy and the high stiffness of the nanographene originate from the response of the benzenoid unit to stress.

ABSTRACT:The response of a nanographene sheet to external stresses is considered in terms of a mechanochemical reaction. The quantum chemical realization of the approach is based on a coordinate-of-reaction concept for the purpose of introducing a mechanochemical internal coordinate (MIC) that specifies a deformational mode. The related force of response is calculated as the energy gradient along the MIC, while the atomic configuration is optimized over all of the other coordinates under the MIC constant-pitch elongation. The approach is applied to the benzene molecule and (5, 5) nanographene. A drastic anisotropy in the microscopic behavior of both objects under elongation along a MIC has been observed when the MIC is oriented either along or normally to the C-C bonds chain. Both the anisotropy and high stiffness of the nanographene originate at the response of the benzenoid unit to stress.Key words: mechanochemical reaction, mechanochemical internal coordinate, uniaxial tension, quantum chemistry, benzene molecule, nanographene Oppositely to real physical experiments, when changing the object shape under loading is usually monitored, computational experiments deal with the total energy response to the object shape deformation that simulates either tension and contraction or bending, screwing, shift, and so forth. As for graphene and carbon nanotubes (CNTs), whose mechanical properties are amenable to experimental study with difficult, the computational experiments takes on great significance.A lot of works are devoted to the calculation of mechanical properties of nanographenes and CNTs in due course of which two approaches, namely, continuum and atomistic ones have been formulated. The continuum approach is based on the well developed theory of elasticity of continuous solid media applied to shells, plates, beams, rods, and trusses. The latter are structure elements used for the continuum description. When applying to either CNT or nanographene, their lattice molecular structure is presented in terms of the above continuum structure elements and the

Neutron powder diffraction and inelastic neutron scattering (INS) were used to determine the structure and hydrogen content of basic structure units (BSUs) of sp2 amorphous carbons at the atomic level. A comparative study of two natural (shungite carbon and antraxolite) and two synthetic (carbon blacks) species of the highest-rank carbonization revealed nanosize stack structure of all samples. The stacks are formed by BSUs representing framed graphene molecules (graphene oxyhydrides) of ∼2.5 nm lateral dimension. The INS study showed the presence of hydrogen atoms in the BSU framing area as well as of adsorbed water in the sample pores configured by BSU stacks. Simulated INS spectra of adsorbed water showed its monolayer disposition within the pores. BSU INS spectra were simulated for a set of particular models simulating H-standard features of the INS spectra of graphene-based species, in general, and BSU hydrogen component of the studied samples, in particular. Simulations were performed in the framework of both spin-independent (density functional theory) and spin-dependent (unrestricted Hartree–Fock) molecular vibrational dynamics. The obtained results allowed a reliable presentation of the hydrogeneous component of the BSU atomic structure and proposing a specific INS classification of sp2 amorphous carbons with respect to their hydrogeneousness.