Crystallinity, carbon/graphite

Graphite anodes are made by mixing calcined petroleum coke particles and coal tar pitch binder. The desired shape is heated at 2800°C in order to convert amorphous carbon to crystalline carbon (graphite), which is immune to chloride solutions [10-11]. These anodes are normally impregnated with linseed oil or synthetic resins for reducing porosity and spalling, hi addition, the anodes are buried in the soil and backfilled with coke breeze for a uniform distribution... 

Crystalline carbons Graphite and its synthetic analogue chaoite and lonsdaleite. 

Carbon Crystalline carbons Graphite, disordered type c Winter (1983)... 

Acetylene black is very pure with a carbon content of 99.7%. It has a surface area of about 65 m /g, an average particle diameter of 40 nm, and a very high but rather weak stmcture with a DBPA value of 250 mL/100 g. It is the most crystalline or graphitic of the commercial blacks. These unique features result in high electrical and thermal conductivity, low moisture absorption, and high Hquid absorption. 

Zimbabwe. This country has one large crystalline flake graphite mine, the Lynx, located between Harare and Lake Kariba. The mine is underground and is being mined on four levels for ore averaging 35% carbon. 

Graphite is a denser crystalline form of carbon. Graphite anodes are prepared by heating calcined petroleum coke particles with a coal tar pitch binder. The mix is then shaped as required and heated to approximately 2 800°C to convert the amorphous carbon to graphite. Graphite has now superseded amorphous carbon as a less porous and more reliable anode material, particularly in saline conditions. 

Carbon. The electronically conductive carbons are derived from the hexagonal crystalline modification—graphite. 

The natural crystalline flake graphite from Zavalie field in Ukraine s Kirovograd Province has been subjected to thermochemical treatment and the resultant product, thermoexfoliated graphite, has been used as carbon material for CM creation. This material was selected because of following considerations ... 

The commonest crystalline forms of carbon, cubic diamond and hexagonal graphite, are classical examples of allotropy that arc found in every chemistry textbook. Both diamond and graphite also exist in two minor crystallographic forms hexagonal diamond and rhombohedral graphite. To these must be added carbynes and Fullerenes, both of which are crystalline carbon forms. FulleTenes are sometimes referred to as the third allotrope of carbon. However, since Fullerenes were discovered more recently than carbynes, they are... 

Synthetics and mineral fibers have other parallels. A few synthesized fibers show a higher level or secondary ordering of the crystalline structure, such as that described for chrysotile. Composed entirely of carbon, graphite fibers are synthetic fibers with such a secondary structure (see the following section). Tubular fibers of other compositions, such as aluminum silicate polymers, have also been synthesized (Farmer et al., 1977). 

The many forms of so-called amorphous (non-crystalline) carbon such as charcoals and lampblack are all actually microcrystalline forms of graphite. The latter has a covalently bonded layer structure comprising a network of joined flat hexagonal Ce rings where the separation of the layers is reported to be 3.35A. This is about equal to the sum of the Van der Waals (intermolecular) radii, indicating that the forces between layers should be relatively slight, as is evidenced by the observed softness and lubricity of the material. 

While diamond is the hardest naturally occurring material, the most common form of crystalline carbon is the much softer and flexible graphite. Graphite occurs as sheets of... 

Boron nitride has two crystalline forms, hexagonal and cubic. These forms are similar to the two common forms of carbon, graphite and diamond. 

The most common of these pigments are certain earths, such as Sienna or Italian earth—which is a brown ochre—umber, Cologne earth or Cassel brown blacks with a carbon basis graphite, consisting of more or less impure crystalline carbon. 

Small carbon grains are assumed to be the carrier of the prominent interstellar ultra violet absorption at 217 nm. To investigate this hypothesis, we produced small carbon particles by evaporating graphite in an inert quenching gas atmosphere, collected the grains on substrates, and measured their optical spectra. In the course of this work - which in the decisive final phase was carried out with the help of K. Fostiropoulos and L. D. Lamb - we showed that the smoke samples contained substantial quantities of C60. The fullerene C60 (with small admixtures of C70) was successfully separated from the sooty particles and, for the first time, characterized as a solid. We suggested the name fullerite for this new form of crystalline carbon. 

Discovery of crystalline solid C60 was actually the finding of a new form of crystalline carbon, being different in dimensionality from graphite, two-dimensional sp2 carbon. It is also different from diamond, three-dimensional sp3 carbon. From this viewpoint, crystalline C60 polymers produced via high-pressure and... 

---