Linear acetylenic carbon (LAC), also known as carbyne or Linear Carbon Chain (LCC), is an allotrope of carbon that has the chemical structure as a repeat unit, with alternating single and triple bonds. It would thus be the ultimate member of the polyyne family.
This polymeric carbyne is of considerable interest to nanotechnology as its Young's modulus is 32.7TPa – forty times that of diamond; this extraordinary number is, however, based on a novel definition of cross-sectional area that does not correspond to the space occupied by the structure. Carbyne has also been identified in interstellar space; however, its existence in condensed phases has been contested recently, as such chains would crosslink exothermically (and perhaps explosively) if they approached each other.
The first claims of detection of this allotrope were made in 1960 and repeated in 1978. A 1982 re-examination of samples from several previous reports determined that the signals originally attributed to carbyne were in fact due to silicate impurities in the samples. Absence of carbyne crystalline rendered the direct observation of a pure carbyne-assembled solid still a major challenge, because carbyne crystals with well-defined structures and sufficient sizes are not available to date. This is indeed the major obstacle to general acceptance of carbyne as a true carbon allotrope. The mysterious carbyne still attracted scientists with its possible extraordinary properties.
During the past thirty five years an increasing body of experimental and theoretical work has been published in the scientific literature dealing with the preparation of carbyne and the study of its structure, properties and potential applications.
In 1968 a silver-white new mineral was discovered in graphitic gneisses of the Ries Crater (Nordlingen, Bavaria, Germany). This material was found to consist entirely of carbon and its hexagonal cell dimensions matched those reported earlier for carbine by Russians scientists.
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Carbon is capable of forming many allotropes (structurally different forms of the same element) due to its valency. Well-known forms of carbon include diamond and graphite. In recent decades, many more allotropes have been discovered and researched, including ball shapes such as buckminsterfullerene and sheets such as graphene. Larger-scale structures of carbon include nanotubes, nanobuds and nanoribbons. Other unusual forms of carbon exist at very high temperatures or extreme pressures.
Graphene (ˈgræfiːn) is an allotrope of carbon consisting of a single layer of atoms arranged in a hexagonal lattice nanostructure. The name is derived from "graphite" and the suffix -ene, reflecting the fact that the graphite allotrope of carbon contains numerous double bonds. Each atom in a graphene sheet is connected to its three nearest neighbors by σ-bonds and a delocalised π-bond, which contributes to a valence band that extends over the whole sheet.
A fullerene is an allotrope of carbon whose molecule consists of carbon atoms connected by single and double bonds so as to form a closed or partially closed mesh, with fused rings of five to seven atoms. The molecule may be a hollow sphere, ellipsoid, tube, or many other shapes and sizes. Graphene (isolated atomic layers of graphite), which is a flat mesh of regular hexagonal rings, can be seen as an extreme member of the family. Fullerenes with a closed mesh topology are informally denoted by their empirical formula Cn, often written Cn, where n is the number of carbon atoms.
The high conductivity of graphene material (or its derivatives) and its very large surface area enhance the direct electron transfer, improving non-enzymatic electrochemical sensors sensitivity and its other characteristics. The offered large pores facilit ...
MDPI2022
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We report experimental studies of spin-wave excitations in individual 22-nm-thick Ni80Fe20 nanotubes with diameters of about 150 nm. We apply Brillouin light-scattering spectroscopy under microwave irradiation, and we resolve sets of discrete resonances in ...
Nanostructured graphitic materials, including graphene hosting Å to nanometer-sized pores, have attracted attention for various applications such as separations, sensors, and energy storage. Graphene with Å-scale pores is a promising next-generation materi ...