However, the electricity is only conducted along the plane of the layers. These electrons are free to move, so are able to conduct electricity. Graphite conducts electricity, due to delocalization of the pi bond electrons above and below the planes of the carbon atoms. Therefore, it is used in thermochemistry as the standard state for defining the heat of formation of carbon compounds. Likewise, under standard conditions, graphite is the most stable form of carbon. Thus, it can be used in, for instance, electrical arc lamp electrodes. Unlike diamond, graphite is an electrical conductor. Graphite, named by Abraham Gottlob Werner in 1789, from the Greek γράφειν ( graphein, "to draw/write", for its use in pencils) is one of the most common allotropes of carbon. Significant research efforts in Japan, Europe, and the United States are under way to capitalize on the potential offered by diamond's unique material properties, combined with increased quality and quantity of supply starting to become available from synthetic diamond manufacturers. Garnering much excitement is the possible use of diamond as a semiconductor suitable to build microchips from, or the use of diamond as a heat sink in electronics. With the continuing advances being made in the production of synthetic diamond, future applications are beginning to become feasible. In addition to mined diamonds, synthetic diamonds found industrial applications almost immediately after their invention in the 1950s another 400 million carats (80 tonnes) of synthetic diamonds are produced annually for industrial use, which is nearly four times the mass of natural diamonds mined over the same period. This helps explain why 80% of mined diamonds (equal to about 100 million carats or 20 tonnes annually) are unsuitable for use as gemstones and known as bort, are destined for industrial use. Industrial diamonds are valued mostly for their hardness and heat conductivity, making many of the gemological characteristics of diamond, including clarity and color, mostly irrelevant. The market for industrial-grade diamonds operates much differently from its gem-grade counterpart. Specialized applications include use in laboratories as containment for high pressure experiments (see diamond anvil), high-performance bearings, and specialized windows of technical apparatuses. Diamonds are embedded in drill tips and saw blades, or ground into a powder for use in grinding and polishing applications (due to its extraordinary hardness). Most uses of diamonds in these technologies do not require large diamonds, and most diamonds that are not gem-quality can find an industrial use. The dominant industrial use of diamond is cutting, drilling ( drill bits), grinding (diamond edged cutters), and polishing. Diamond is thermodynamically less stable than graphite at pressures below 1.7 GPa. This network of unstrained covalent bonds makes diamond extremely strong. The bonding occurs through sp 3 hybridized orbitals to give a C-C bond length of 154 pm. These tetrahedrons together form a 3-dimensional network of six-membered carbon rings in the chair conformation, allowing for zero bond angle strain. Each carbon atom is covalently bonded to four other carbons in a tetrahedral geometry. The crystal structure of diamond is a face-centred cubic lattice having eight atoms per unit cell to form a diamond cubic structure. In diamond form, carbon is one of the costliest elements. No known naturally occurring substance can cut or scratch diamond, except another diamond. This makes it an excellent abrasive and makes it hold polish and luster extremely well. Diamond is the hardest known natural mineral. The hardness, extremely high refractive index, and high dispersion of light make diamond useful for industrial applications and for jewellery. Missing: cyclocarbon, carbon nanobuds, schwarzites, glassy carbon, and linear acetylenic carbon (carbyne) Part of a series of articles onĭiamond is a well-known allotrope of carbon. Eight allotropes of carbon: (a) diamond, (b) graphite, (c) lonsdaleite, (d) C 60 buckminsterfullerene, (e) C 540 fullerite (f) C 70 fullerene, (g) amorphous carbon, (h) zig-zag single-walled carbon nanotube. Two familiar allotropes of carbon: graphite and diamond.
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