Chemical Fact Sheet
Carbon
| Chemical Abstract Number (CAS #) | 7440-44-0 |
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| 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 |
| Molecular Formula | C |
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Synopsis
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Carbon - (L. carbo, charcoal), C; at. wt. 12.011(l); at. no. 6; m.p. ~3550 deg C, Graphite sublimes at 3825 deg C; triple point; (graphite-liquid-gas), 4492 deg C at a pressure of 10.3 MPa and (graphite-diamond-liquid), 3830-3930 deg at a pressure of 12-13 GPa; 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 deg 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 of ancient volcanic "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 well-known carbon-nitrogen cycle. Carbon is found free in nature in three allotropic forms: amorphous, graphite, and diamond. A fourth form, known as "white" carbon, is now thought to exist. 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 1OOO deg C. In 1969 a new allotropic form of carbon was produced during the sublimation of pyrolytic graphite at low pressures. Under free-vaporization conditions above ~2550 K, "white" carbon forms as small transparent crystals on the edges of the basal planes of graphite. The interplanar spacings of "white" carbon are identical to those of carbon form noted in the graphitic gneiss from the Ries (meteoritic) Crater of Germany. "White" carbon is a transparent birefringent material. Little information is presently available about this allotrope. 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 imossible. 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% C02. 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 thirteen 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. |
| Use | AS STRONG REDUCING AGENT AND IS USED AS SUCH IN PURIFYING METALS; IN ELECTRODES, ELECTRICAL DEVICES & STEEL TRACER RESEARCH & CHEMICAL DATING JEWELRY; POLISHING, GRINDING, CUTTING GLASS, BEARINGS FOR DELICATE INSTRUMENTS; MFR DIES FOR TUNGSTEN WIRE & SIMILAR HARD WIRES; MAKING STYLI FOR RECORDER HEADS; LONG-LASTING PHONOGRAPH NEEDLES; IN SEMICONDUCTOR RESEARCH FOR "LEAD" PENCILS; REFRACTORY CRUCIBLES; STOVE POLISH; AS PIGMENT, LUBRICANT, GRAPHITE CEMENT; FOR MATCHES & EXPLOSIVES; COMMUTATOR BRUSHES; ANODES; ARC-LAMP CARBONS; ELECTROPLATING; POLISHING COMPD, RUST & NEEDLE-PAPER; COATING FOR CATHODE RAY TUBES; MODERATOR IN NUCLEAR PILES MEDICATION: ACTIVATED CHARCOAL AS ANTIDOTE; ADSORPTIVE; VET: INTERNALLY AS AN ADSORPTIVE IN DIARRHEA; EXTERNALLY IN FOUL WOUNDS RADIATION SOURCE IN THICKNESS GAUGES & OTHER INSTRUMENTS; ELUCIDATION OF MECHANISMS IN ORG CHEM, METALLURGY, & BIOCHEMICAL REACTIONS USED CHIEFLY FOR CLARIFYING, DEODORIZING, DECOLORIZING & FILTERING; PIGMENT FOR RUBBER TIRES; FOR PRINTING, STENCILING & DRAWING INKS; FOR LEATHER; STOVE POLISH; PHONOGRAPH RECORDS; ELECTRICAL INSULATING APPARATUS DECOLORIZING AGENT IN REFINING PROCESS FOR SUGARS; ADSORPTIVE FOR REMOVING CONTAMINANTS FROM DRINKING WATER; ADSORPTIVE IN WASTEWATER TREATMENT SYSTEMS; ADSORPTIVE FOR FOODS & BEVERAGES-EG, ODOR & TASTE REMOVAL; ADSORPTIVE FOR FUEL VAPORS IN AUTOMOTIVE EXHAUST SYSTEMS; FILTERING AID IN FILTERED CIGARETTES; ADSORPTIVE FOR VOLATILE SOLVENT RECOVERY; ADSORPTIVE IN MFG OF PHARMACEUTICALS, EG, COLOR REMOVAL; ADSORPTIVE FOR IMPURITIES IN DRY CLEANING SOLNS; ADSORPTIVE IN MINING PROCESSES; CATALYST, EG, FOR PREPN OF PHOSGENE & ISOCYANATES; ADSORPTIVE FOR IMPURITIES IN RECIRCULATING AIR Special surgical knives, windows in space probes, high capacity transmitters Oil well drill bits, primary grinding of steel, wire-drawing dies, glass & metal cutting, grinding wheels Air purification, removal of sulfur dioxide from stack gasses and "clean" rooms, deodorant, removal of jet fumes from airports, catalyst for natural gas purification, brewing, chromium electroplating, air conditioning The carbonaceous residue of the destructive distillation of bituminous coal petroleum, and coal-tar pitch. The principal type is that produced by heating bituminous coal in chemical recovery or beehive coke ovens (metallurgical coke), one ton of coal yielding approximately 0.7 ton of coke. Used chiefly for the reduction of iron ore in blast furnaces, and as a source of synthetic gas. Coke from petroleum residues and coal-tar pitch is used for refractory furnace linings in the electrorefining of aluminum and other high temperature services, and for electrodes in electrolytic reduction of Al203 to aluminum, as well as in electrothermal production of phosphorus, silicon carbide, and calcium carbide |
| Consumption Patterns | LIQUID PHASE APPLICATIONS: SUGAR DECOLORIZING,24%; DRINKING WATER, 21%; WASTEWATER, 16%; FATS, OILS, FOODS, BEVERAGES, 5%; PHARMACEUTICALS, 4%; MINING, 4%; DRY CLEANING, 3%; ELECTROPLATING, 1%; OTHER, 7%; GAS PHASE APPLICATIONS: AUTOMOTIVE, 5%; CIGARETTES, 2%; SOLVENT VAPOR RECOVERY, 2%; CATALYSTS, 1%; RECIRCULATING AIR PURIFICATION, 1%; OTHER, 3% [R1] CHEMICAL PROFILE: Activated Carbon. Water treatment, 30%; (drinking water, 15%; industrial and municipal wastewater, 12%; groundwater, 3%); sugar and corn syrup decolorizing, 14%; gas phase uses (automotive evaporation control, cigarettes, solvent recovery, air purification), 18%; food and pharmaceuticals, 8%; miscellaneous (includes mining, dry cleaning, and electroplating), 15%; exports, 15%. CHEMICAL PROFILE: Activated carbon. Demand: 1988: 233 million lb; 1989: 242 million lb; 1993 projected: 283 million lb. (Includes exports but not imports which totaled 38.8 million lb last year.) |
| Molecular Weight | 12.000 |
| Sensitivity Data | THE DUST IS MILDLY IRRITATING TO LUNGS. In the form of graphite it can cause a dust irritation, particularly to the eyes. It can also cause conjunctivitis epithelial hyperplasia of cornea, as well as eczematous inflammation of eyelids. Some forms of carbon dust can cause irritation of eyes and mucous membranes. |
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Chemical and Physical Properties |
ATOMIC NUMBER: 6; VALENCE: 4; STABLE ISOTOPES: 12 (98.892%); 13 (1.108%); RADIOACTIVE ISOTOPES: 9-11; 14-16 NONMETALLIC ELEMENT; DIVALENT FORMS ARE KNOWN (CARBENES); FORMS BINARY CMPD CALLED CARBIDES WITH MANY METALS & SOME NONMETALS STRONG REDUCING AGENT STRONG ELECTRICAL CONDUCTIVITY ATOMIC RADIUS: 0.77 A; IONIC (CRYSTAL) RADII: 2.60 A (-4 OXIDATION STATE); 0.15 A (+4 OXIDATION STATE); ORBITAL ELECTRONS: [HE]2S2-2PS; ELECTRONEGATIVITY (PAULING SCALE): 2.5 COLORLESS, CUBIC CRYSTALS; INSOL IN WATER, ACID, ALKALI; INDEX OF REFRACTION: 2.4173; DENSITY: 3.51; MP: GREATER THAN 3550 DEG C; BP: 4827 DEG C BLACK HEXAGONAL CRYSTALS; INSOL IN WATER, ACID, ALKALI; SOL IN LIQUID IRON; DENSITY: 2.25 @ 20 DEG C; SUBLIMES: 3652-3697 DEG C; BP: 4827 DEG C AMORPHOUS BLACK CRYSTALS; INSOL IN WATER, ACID, ALKALI; DENSITY: 1.8-2.1; BP: 4827 DEG C; SUBLIMES: 3652-3697 DEG C SMALL TRANSPARENT CRYSTALS FORMED DURING SUBLIMATION OF PYROLYTIC GRAPHITE @ LOW PRESSURES & APPROX 2550 DEG K ("WHITE" CARBON) THE (12)C ISOTOPE, WHICH COMPRISES 99% OF THE ELEMENT, IS THE STANDARD TO WHICH ATOMIC WEIGHTS OF ALL OTHER ELEMENTS ARE REFERRED (C= 12.00 EXACTLY). ONE MOLE OF CARBON ATOMS (6.02X10+23) IS CONTAINED IN 12 G OF (12)C. GRAPHITE IS ONE OF THE SOFTEST KNOWN MATERIALS WHILE DIAMOND IS ONE OF THE HARDEST. GRAPHITE EXISTS IN TWO FORMS: ALPHA & BETA. THESE HAVE IDENTICAL PHYSICAL PROPERTIES, EXCEPT FOR THEIR CRYSTAL STRUCTURE. NATURALLY OCCURRING GRAPHITES CONTAIN 30% RHOMBOHEDRAL (BETA) FORM, WHEREAS SYNTHETIC CONTAIN ONLY ALPHA FORM. "WHITE" CARBON IS A TRANSPARENT BIREFRINGENT MATERIAL. LITTLE INFORMATION IS PRESENTLY AVAIL ABOUT THIS ALLOTROPE. BECAUSE (14)C DECAYS WITH T/2 OF 5760 YR. ORGANIC MATTER (NOT MORE THAN 40,000 YR OLD) CAN BE DATED BY COMPARISON WITH THE STANDARD 15.3 DISINTEGRATIONS/MIN/G. The element carbon, due to its high heat capacity per unit weight, high energy of vaporization, and high temperature and pressure required for melting, has the highest "heat of ablation" (energy absorbed per mass lost) of any material, provided that mechanical removal of particulates does not occur |
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Environmental Fate |
ABUNDANCE IN EARTH'S CRUST: APPROX 0.027%. COSMIC ABUNDANCE: 6 ATOMS/ATOM SI. OCCURS IN 3 FORMS: (1) DIAMOND; (2) GRAPHITE OR BLACK LEAD; (3) AMORPHOUS CARBON SUCH AS COAL, LAMPBLACK, & VARIOUS FORMS OF ARTIFICIAL CARBON. [R9, 250] VERY WIDELY DISTRIBUTED IN NATURE. IT IS FOUND IN ABUNDANCE IN THE SUN, STARS, COMETS, & ATMOSPHERES OF MOST PLANETS. (14)C ISOTOPE, CONTINUOUSLY FORMED IN EARTH'S ATMOSPHERE BY BOMBARDMENT OF NITROGEN WITH COSMIC NEUTRONS IS RAPIDLY OXIDIZED TO CARBON DIOXIDE WHICH PENETRATES INTO ANIMALS & PLANTS BY PHOTOSYNTHESIS & METABOLISM. (14)C CONTENT OF LIVING MATTER IS EST @ 15.3 DISINTEGRATIONS/MIN & PER G OF CARBON, CORRESPONDING TO EQUILIBRIUM REACHED BETWEEN FORMATION OF (14)C & ITS EXCHANGE WITH (12)C. THIS EQUILIBRIUM STOPS WHEN PLANT OR ANIMAL DIES, & (14)C CONTENT BEGINS TO DECR, BECAUSE (14)C DECAYS WITH T/2 OF 5760 YEARS. CARBON IN FORM OF MICROSCOPIC DIAMONDS IS FOUND IN SOME METEORITES. NATURAL DIAMONDS FOUND IN KIMBERLITE OF ANCIENT VOLCANIC "PIPES" IN SOUTH AFRICA, ARKANSAS, DIAMONDS ALSO BEING RECOVERED FROM OCEAN FLOOR OFF CAPE OF GOOD HOPE. Diamond, an allotropic form of carbon, crystallizes isometrically, consists of carbon atoms covalently bound by single bonds only in a predominantly octahedral structure. The purest diamonds used for gems are mined in South Africa, lower grades in Brazil, Venezuela, India, Borneo, Arkansas. Carbon cycle: The process of carbon from air (CO2) to plants by photosynthesis then through the metabolism of animals to decomposition products which ultimately return it to the atmosphere in the form of carbon dioxide. |
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Disposal |
At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices. +Landfill & incineration: Scrap carbon black may be disposed of in an approved landfill, provided that it is handled in a manner that is not hazardous to the surroundings. It can also be disposed of by burning, for example as a slurry in water in a specially designed incinerator. |
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