Structural aspects and conformation of linear carbon polytypes (carbynes)

Dynamic Pressure Synthesis of Carbynes

“…The formation of carbyne has been confirmed in studies on intercalation of metals into polyacetylene under quasi-hydrostatic pressure of 20-40 kbar [29], and in experiments on intercalation of carbyne prepared by chemical dehydrochlorination of poly(vinylidene chloride) (PVOC) powder mixed with potassium hydroxide in ethanol and THF [30] using a procedure reported in [31]. Adapting the kinked-chain model [32] to the results of the analysis conducted on the products of intercalation, a structure of linear carbon chains with intercalated Na atoms (CIC-Na) was proposed to explain the observed diffraction pattern shown in Table VI.…”

“…Combining the kink-chain model [32] with the possible presence of intercalated metal atoms [29,30] and the presence of Sp_Sp2 atoms in such a structure, an "intuitive" unit cell of a carbyne material was proposed recently (see Chapter 6.4.). …”

Dehydroplycondensation of acetylene

“…The former was assigned to intermolecular interference in a bundle of closely packed polyyne chains of carbon, and the latter is attributable to intramolecular interference in a carbon chain. However, in view of the existence of more than ten distinct crystallographic modifications of carbyne reported to date [21,22], this assignment appears to be highly questionable, and the use of crystallographically derived terms, viz., aand ~-carbyne, for describing the type of chemical bonds in carbynes may turn out to be incorrect. These data are attributable to the presence of a considerable amount of amorphous matter [8,12,13].…”

High-Pressure Structural Transformations of Carbyne

“…Since carbon is a low-Z element, the density of carbon materials is rather low, while the strong covalent bonding in these materials leads to record levels of mechanical properties and high thermal stability. The discovery of new carbon allotropes, such as fullerenes [1], nanotubes [2], and carbynes (polymer chain compounds) [3][4][5][6][7]; the synthesis of various sp 2sp 3 amorphous phases [8,9]; and the theoretical prediction of new stable carbon structures [10][11][12][13][14][15] demonstrate that carbon has exceptional potential for solidstate physics and materials research.…”

“…Carbyne, one of the carbon allotropes, exists in a number of crystalline and amorphous forms [3][4][5][6][7] consisting of quasi-one-dimensional carbon chains. The carbon atoms in the chains are predominantly in sp (divalent) states.…”