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Chemical Fact Sheet

Carbon

Chemical Abstract Number (CAS #) 7440-44-0
Synonyms ACETYLENE-BLACK; ACTICARBONE; ACTIVATED-CARBON; ADSORBIT; AG-3- [ADSORBENT]; AG-5- [ADSORBENT]; AK- [ADSORBENT]; ANTHRASORB-; AQUA-NUCHAR-; AR-3-; ART-2-; AU-3-; BAU-; BENZOL-BLACK-; BLACK-140-; BLACK-PEARLS-; CALCOTONE-BLACK-; CARBOLAC-; CARBON-12; CARBOPOL-EXTRA; CARBOPOL-M; CARBOPOL-Z-4; CARBOPOL-Z-EXTRA; CLF-II; CMB-200; CMB-50; COKE-POWDER; COLUMBIA-LCK; CONDUCTEX; CWN-2; FILTRASORB; FILTRASORB-200; FILTRASORB-400; GROSAFE; IRGALITE-1104; K-257; MA-100- [CARBON]; NORIT; OU-B; PELIKAN-C-11/1431A; SKG; SKT; SKT- [ADSORBENT]; SU2000-; SUCHAR-681; SUPERSORBON-IV; SUPERSORBON-S1; WITCARB-940; XE-340-; XF-4175L
Analytical Methods SM5310
Atomic Symbol C

Synopsis from the CRC Handbook of Chemistry and Physics 92nd Edition 2011-2013

Carbon — (L. carbo, charcoal), C; at. wt. 12.0107(8); at. no. 6; sublimes at 3825 °C; triple point (graphite-liquid-gas), 4489 °C; sp. gr. amorphous 1.8 to 2.1, graphite 1.9 to 2.3, diamond 3.15 to 3.53 (depending on variety); gem diamond 3.513 (25 °C); valence 2, 3, or 4. Carbon, an element of prehistoric discovery, is very widely distributed in nature. It is found in abundance in the sun, stars, comets, and atmospheres of most planets. Carbon in the form of microscopic diamonds is found in some meteorites. Natural diamonds are found in kimberlite or lamporite of ancient formations called “pipes,” such as found in South Africa, Arkansas, and elsewhere. Diamonds are now also being recovered from the ocean floor off the Cape of Good Hope. About 30% of all industrial diamonds used in the U.S. are now made synthetically. The energy of the sun and stars can be attributed at least in part to the wellknown carbon-nitrogen cycle. Carbon is found free in nature in three allotropic forms: amorphous, graphite, and diamond. Graphite is one of the softest known materials while diamond is one of the hardest. Graphite exists in two forms: alpha and beta. These have identical physical properties, except for their crystal structure. Naturally occurring graphites are reported to contain as much as 30% of the rhombohedral (beta) form, whereas synthetic materials contain only the alpha form. The hexagonal alpha type can be converted to the beta by mechanical treatment, and the beta form reverts to the alpha on heating it above 1000 °C. Of recent interest is the discovery of all-carbon molecules, known as “buckyballs” or fullerenes, which have a number of unusual properties. These interesting molecules, consisting of 60 or 70 carbon atoms linked together, seem capable of withstanding great pressure and trapping foreign atoms inside their network of carbon. They are said to be capable of magnetism and superconductivity and have potential as a nonlinear optical material. Buckyball films are reported to remain superconductive at temperatures as high as 45 K. In combination, carbon is found as carbon dioxide in the atmosphere of the Earth and dissolved in all natural waters. It is a component of great rock masses in the form of carbonates of calcium (limestone), magnesium, and iron. Coal, petroleum, and natural gas are chiefly hydrocarbons. Carbon is unique among the elements in the vast number and variety of compounds it can form. With hydrogen, oxygen, nitrogen, and other elements, it forms a very large number of compounds, carbon atom often being linked to carbon atom. There are close to ten million known carbon compounds, many thousands of which are vital to organic and life processes. Without carbon, the basis for life would be impossible. While it has been thought that silicon might take the place of carbon in forming a host of similar compounds, it is now not possible to form stable compounds with very long chains of silicon atoms. The atmosphere of Mars contains 96.2% CO2. Some of the most important compounds of carbon are carbon dioxide (CO2), carbon monoxide (CO), carbon disulfide (CS2), chloroform (CHCl3), carbon tetrachloride (CCl4), methane (CH4), ethylene (C2H4), acetylene (C2H2), benzene (C6H6), ethyl alcohol (C2H5OH), acetic acid (CH3COOH), and their derivatives. Carbon has fifteen isotopes. Natural carbon consists of 98.89% 12C and 1.11% 13C. In 1961 the International Union of Pure and Applied Chemistry adopted the isotope carbon-12 as the basis for atomic weights. Carbon-14, an isotope with a half-life of 5715 years, has been widely used to date such materials as wood, archeological specimens, etc. A new brittle form of car- 4-8 The Elements bon, known as “glassy carbon,” has been developed. It can be obtained with high purity. It has a high resistance to corrosion, has good thermal stability, and is structurally impermeable to both gases and liquids. It has a randomized structure, making it useful in ultra-high technology applications, such as crystal growing, crucibles for high-temperature use, etc. Glassy carbon is available at a cost of about $35/10g. Fullerene powder is available at a cost of about $55/10mg (99%C10). Diamond powder (99.9%) costs about $40/g.


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