Fullerenes molecular crystals

Karataev, V. I. (1998). Anomalous properties of C74 fullerene. Molecular Crystals and Liquid Crystals Science and Technology Section C-Molecular... 

J.E. Fischer and a team of researchers (University of Pennsylvania) report, The recent discovery of an efficient synthesis of C and C711... has facilitated the study of a new class of molecular crystals Cfullcrilcs ) based on these molecules ( fullerenes ). In the Fischer reference listed, a study of the compressibility of solid is described. 

The first discovered solid phase of fullerenes C6o represents typical molecular crystal. Later it was established that high pressure applied to solid C6o at high temperature induces polymerization of C6o [1-2]. Using the computer modeling methods allows confirming the existence of at least three different planar polymerized structures of fullerene Cgo with coordination numbers 2, 4, 6, and besides the values 4 and 6 are more probable ones. 

In this section, I have included a few of my papers dealing with synthesis, defects and certain properties of oxidic materials and fullerenes, besides a general article dealing with important directions in materials chemistry. There is also an article dealing with experimental charge densities in organic molecular crystals. These articles should indicate the diversity and breadth of coverage in materials chemistry. 

In this entry, the principal chemical features of defect populations (defect chemistry) will be described from the restricted viewpoint of crystalline inorganic solids. The influence of defects upon mechanical properties will be excluded and defects that may have greatest relevance to physical properties will be treated from the point of view of chemical importance. Defects in molecular crystals and amorphous and glassy solids will be omitted see Noncrystalline Solids), as will the important areas of alloys see Alloys), thin films see Thin Film Synthesis of Solids), and carbon nanotubes and related nanoparticles see Carbon Fullerenes). References to the literature before 1994 are to be found in the corresponding article in the first edition of this Encyclopedia. ... 

Among the few determinations of of molecular crystals, the CPHF/ INDO smdy of Yamada et al. [25] is unique because, on the one hand, it concerns an open-shell molecule, the p-nitrophenyl-nitronyl-nitroxide radical (p-NPNN) and, on the other hand, it combines in a hybrid way the oriented gas model and the supermolecule approach. Another smdy is due to Luo et al. [26], who calculated the third-order nonlinear susceptibility of amorphous thinmultilayered films of fullerenes by combining the self-consistent reaction field (SCRF) theory with cavity field factors. The amorphous namre of the system justifies the choice of the SCRF method, the removal of the sums in Eq. (3), and the use of the average second hyperpolarizability. They emphasized the differences between the Lorentz Lorenz local field factors and the more general Onsager Bbttcher ones. For Ceo the results differ by 25% but are in similar... 

Thus the thermodynamic characteristics of adsorption at small coverage of different classes organic compounds determined by gas chromatography show that surface of ful-lerene molecular crystals and surface of graphitized carbon black have essentially different adsorption properties. On adsorption on fullerene crystals the electron-acceptor and electron-donor properties of fullerene molecules are manifested. Adsorption data on fullerenes Ceo nd C70 show that properties of fullerene Ceo a-nd C70 molecules arranged in surface layer of crystals are different. 

There is also a distinction to be drawn between nanoscience and nanotechnology. Nanoscience is the sub-discipline of science that involves the study of nanoscale materials, processes, phenomena and/or devices. Nanoscience includes materials and phenomena at the nanoscale (typically 0.1-100 nm) hence, it includes areas such as carbon nanoscience (e.g. fullerenes), molecular scale electronics, molecular self-assembly, quantum size effects and crystal engineering. Nanotechnology involves the design, characterization, manipulation, incorporation and/or production of materials and structures in the nanoscale range. These applications exploit the properties of the nanoscale components, distinct from bulk or macroscopic systems. Naturally, there is a substantial overlap of scale between nanotechnology and colloid technology. 

Molecular Crystals Fullerites. Organic crystals are usually prone to ionization damage and decompose very rapidly under electron irradiation they can thus be studied for only a short time (a few. seconds) and only with a very low electron beam intensity. Transmission electron microscopy has, therefore, seldom been applied to organic crystals. However, the all-carbon molecules Qo, C70. etc., (fullerenes) discovered at the end of the 1980s resist electron radiation fairly well. Early structural studies on the crystalline phases of ftil-lerenes (fullerites) were performed mainly by electron microscopy because only small quantities of sufficiently pure material were available. At room... 

Miyake, Y., Minami, T> Kikuchi, K.> Kainosho, M., 8c Achiba, Y. (2000). Trends in structure and growth of higher fullerenes isomer structure of Cg6 and Molecular Crystals and Liquid Crystals, 340, 553-558. 

Pekker et al., 2005] S. Pekker et al. Rotor-stator molecular crystals of fullerenes with cubane. Nature Materials 4 764-767, 2005. 

Fullerenes are described in detail in Chapter 2 and therefore only a brief outline of their structure is presented here to provide a comparison with the other forms of carbon. The C o molecule, Buckminsterfullerene, was discovered in the mass spectrum of laser-ablated graphite in 1985 [37] and crystals of C o were fust isolated from soot formed from graphite arc electrodes in 1990 [38]. Although these events are relatively recent, the C o molecule has become one of the most widely-recognised molecular structures in science and in 1996 the codiscoverers Curl, Kroto and Smalley were awarded the Nobel prize for chemistry. Part of the appeal of this molecule lies in its beautiful icosahedral symmetry - a truncated icosahedron, or a molecular soccer ball, Fig. 4A. 

Since the structure and properties of fullerene solids are strongly dependent on the structure and properties of the constituent fullerene molecules, we first review the structure of the molecules, which is followed by a review of the structure of the molecular solids formed from Ceo, C70 and higher mass fullerenes, and finally the structure of Cgo crystals. 

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