Properties of Carbon

Discuss this statement as it applies to the Group IV elements, C, Si, Ge, Sn, Pb, indicating any properties of carbon which appear anomalous. Illustrate your answer by considering ... 

Oxygen is the most abundant element on earth The earths crust is rich in carbonate and sili cate rocks the oceans are almost entirely water and oxygen constitutes almost one fifth of the air we breathe Carbon ranks only fourteenth among the elements in natural abundance but trails only hydro gen and oxygen in its abundance in the human body It IS the chemical properties of carbon that make it uniquely suitable as the raw material forthe building blocks of life Let s find out more about those chemi cal properties... 

During the nineteenth century the growth of thermodynamics and the development of the kinetic theory marked the beginning of an era in which the physical sciences were given a quantitative foundation. In the laboratory, extensive researches were carried out to determine the effects of pressure and temperature on the rates of chemical reactions and to measure the physical properties of matter. Work on the critical properties of carbon dioxide and on the continuity of state by van der Waals provided the stimulus for accurate measurements on the compressibiUty of gases and Hquids at what, in 1885, was a surprisingly high pressure of 300 MPa (- 3,000 atmor 43,500 psi). This pressure was not exceeded until about 1912. 

Table 3. Properties of Carbon Black-Filled Natural Rubber Vulcanizates With Various Cure Systems ...

Table 3. Physical Properties of Carbon and Silicon and Their Bonds to Hydrogen ...

The physical properties of carbon electrodes are deterrnined by the raw materials and processes used in their manufacturer. There are no universal grade designations and the pubHshed properties are quite broad. Table 3 shows ranges for some of the common commercially available grades. 

Table 1. Mechanical and Physical Properties of Carbon Fibers ...

Most recent studies (69) on elevated temperature performance of carbon fiber-based composites show that the oxidation resistance and elevated temperature mechanical properties of carbon fiber reinforced composites are complex and not always direcdy related to the oxidation resistance of the fiber. To some extent, the matrix acts as a protective barrier limiting the diffusion of oxygen to the encased fibers. It is therefore critical to maintain interfacial bonding between the fiber and the matrix, and limit any microcracking that may serve as a diffusion path for oxygen intmsion. Since interfacial performance typically deteriorates with higher modulus carbon fibers it is important to balance fiber oxidative stabiHty with interfacial performance. 

Available data on the thermodynamic and transport properties of carbon dioxide have been reviewed and tables compiled giving specific volume, enthalpy, and entropy values for carbon dioxide at temperatures from 255 K to 1088 K and at pressures from atmospheric to 27,600 kPa (4,000 psia). Diagrams of compressibiHty factor, specific heat at constant pressure, specific heat at constant volume, specific heat ratio, velocity of sound in carbon dioxide, viscosity, and thermal conductivity have also been prepared (5). 

The following tables of properties of carbon dioxide are available enthalpy, entropy, and heat capacity at 0 and 5 MPa (0 and 50 atm, respectively) from 273 to 1273 K pressure—volume product (PV), enthalpy, and isobaric heat capacity (C from 373 to 1273 K at pressures from 5 to 140 MPa (50-1,400 atm) (14). 

The physical and thermodynamic properties of carbon monoxide are well documented in a number of excellent summaries (1 8). The thermochemical data cited here are drawn predominantly from references 1—3 physical property data from reference 5. A summary of particularly useful physical constants is presented in Table 1. 

The physical properties of carbon tetrachloride are Hsted in Tables 1 and 2. 

Table 1. Some properties of carbon-carbon bonds...

The diameter distribution of single-wall carbon nanotubes is of great interest for both theoretical and experimental reasons, since theoretical studies indicate that the physical properties of carbon nanotubes are strongly dependent on the nanotube diameter. Early results for the diameter distribution of Fe-catalyzed single-wall nanotubes (Fig. 15) show a diameter range between 0.7 nm and 1.6 nm, with the largest peak in the distribution at 1.05 nm, and with a smaller peak at 0.85 nm [154]. The smallest reported diameter for a single-wall carbon nanotube is 0.7 nm [154], the same as the diameter of the Ceo molecule (0.71 nm) [162]. 

Hamada, T., Nishida, T., Sajiki, Y. and Matsumoto, M., Structures and physical properties of carbon fibers from coal tar mesophase pitch, J Mat Res, 1987, 2(6), 850 857. 

Low density, carbon fiber-carbon binder composites are fabricated from a variety of carbon fibers, including fibers derived from rayon, polyacrylonitrile (PAN), isotropic pitch, and mesophase pitch. The manufacture, structure, and properties of carbon fibers have been thoroughly reviewed elsewhere [3] and. therefore, are... 

The term activation refers to the development of the adsorption properties of carbon. Raw materials such as coal and charcoal do have some adsorption capacity, but this is greatly enhanced by the activation process. There are three main forms of activated carbon. 

Abstract—The fundamental relations governing the geometry of carbon nanotubes are reviewed, and explicit examples are pre.sented. A framework is given for the symmetry properties of carbon nanotubes for both symmorphic and non-symmorphic tubules which have screw-axis symmetry. The implications of symmetry on the vibrational and electronic structure of ID carbon nanotube systems are considered. The corresponding properties of double-wall nanotubes and arrays of nanotubes are also discussed. 

This journal issue features the many unusual properties of carbon nanotubes. Most of these unusual properties are a direct consequence of their ID quantum behavior and symmetry properties, including their unique conduction propertiesjll] and their unique vibrational spectra[8]. 

ELECTRONIC PROPERTIES OF CARBON NANOTUBES EXPERIMENTAL RESULTS... 

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