IB Chemistry higher level notes: Allotropes of carbon IB syllabus for first examinations 2016 14.4 - Allotropes of carbon 14.4.1 Describe and explain the structures and properties of diamond, graphite and fullerene. Students should recognize the type of hybridization present in each allotrope and the delocalization of electrons in graphite and C60 fullerene. Allotropy Allotropes are different physical forms of the same element. All elements are made up uniquely of their own atoms and therefore any physical differences must be a consequence of how the atoms are joined together - their arrangement within the bulk structure. Many elements exhibit allotropy as there are often varous ways in which the atoms can be linked together into molecules and also different ways in which the molecules can be arranged to make larger structures.

In the case of carbon, the atoms form either giant macromolecular structures (diamond and graphite) in which all of the atoms in the bulk structure are joined together by covalent bonds making giant molecules, or smaller molecules (buckminster fullerene) in which there are only discrete molecules made up of 60 carbons in a structure resembling a football (hence the nickname 'bucky balls') Diamond Each carbon in a diamond crystal is bonded to four other carbon atoms making a giant macromolecular array (lattice). As each carbon has four single bonds it is sp3 hybridised and has tetrahedral bond angles of 109º 28' Properties of diamond Hard Many strong covalent bonds holding the structure together Click on the image with the left mouse button and drag to get a different view. (if you can't see the image you have to download chime ) Brittle All of the bonds are directional and stress will tend to break the structure (In a malleable substance, such as for example a metal, the bonding is non-directional and can still act if the particles are displaced with respect to one another). Insulator All of the valence (outer shell) electrons are used in bonding.

The bonds are sigma and the electrons are located between the two carbon nuclei being bonded together. None of the electrons are free to move Insoluble There are only very weak Van der Waal's attractions between the carbon atoms and the water molecules whereas the carbon atoms are bodned very tightly to one another. Very high melting point Many strong covalent bonds holding the structure together - it requires massive amounts of energy to pull it apart Graphite Again the carbon atoms are bonded together to make a giant structure but in this case all of the carbons are bonded to only three neighbour and are sp2 hybridised. As the sp2 hybridisation results in planar structures, there are giant 2 dimensional layers of carbon atoms and each layer is only weakly linked to the next layer by Van der Waal's forces. Physical properties of graphite explained by considering the structure and bonding Property Graphite structure Soft and slippery Many strong covalent bonds holding the structure together but only in 2 dimensions. The layers are free to slide easily over one another. Graphite powder is used as a lubricant. Click on the image with the left mouse button and drag to get a different view.

(if you can't see the image you have to download chime ) Brittle All of the bonds are directional within a layer and stress across a layer will tend to break them. Graphite rods used for electrolysis easily break when dropped. Electrical conductor Only three of the valence (outer shell) electrons are used in sigma bonding. The other electron is in a 'p' orbital which can overlap laterally with neighbouring 'p' orbitals making giant molecular pi orbitals that extend over the whole of each layer. Electrons are free to move within these delocalised pi orbitals. Insoluble in water. There are only very weak Van der Waal's attractions between the carbon atoms and the water molecules whereas the carbon atoms are bonded very tightly to one another. V. high melting point Many strong covalent bonds holding the layers together - it requires massive amounts of energy to pull it apart Fullerenes These are small molecules of carbon in which the giant structure is closed over into spheres of atoms (bucky balls) or tubes (sometimes caled nano-tubes). The smallest fullerene has 60 carbon atoms arranged in pentagons and hexagons like a football. This is called Buckminsterfullerene.

The name 'buckminster fullerene' comes from the inventor of the geodhesic dome (Richard Buckminster Fuller) which has a similar structure to a fullerene. Fullerenes were first isolated from the soot of chimineys and extracted from solvents as red crystals. The bonding has delocalised pi molecular orbitals extending throughout the structure and the carbon atoms are a mixture of sp2 and sp3 hybridised systems. Fullerenes are insoluble in water but soluble in methyl benzene. They are non- conductors as the individual molecules are only held to each other by weak van der Waal's forces. Buckminster fullerene Structure As the molecule is totally symmetrical with all bond lengths and angles being equal, it is likely/inevitable that the hybridisation of the carbon atoms is somewhere between that of sp2 and sp3. Another example of a theory (hybridisation in this case) having to be modified to accomodate the observed experimental data.

Physical properties of fullerenes explained by considering the structure and bonding Property BBC - GCSE Bitesize: Fullerenes Fullerenes Structure of a buckminsterfullerene molecule - a large ball of 60 atoms The fullerenesfullerene: Molecules made up entirely of carbon in the shape of a sphere or tube. are a large class of allotropes of carbon and are made of balls, ‘cages’ or tubes of carbon atoms. Buckminster fullerene is one type of fullerene. Its molecules have 60 carbon atoms arranged in a hollow sphere. Nanotubes Nanotubesnanotube: A hollow cylindrical molecule usually made of carbon for use in nanotechnology. are fullerenes that can be used to reinforce graphite in tennis rackets because they are very strong. They are also used as semiconductors in electrical circuits. The nanotube's structure allows it to be used as a container for transporting a drug in the body. A molecule of the drug can be placed inside the nanotube cage. This keeps the drug 'wrapped up' until it reaches the site where it is needed.

In this way, a dose that might be damaging to other parts of the body can be delivered safely to, for example, a tumour. Now try a Test Bite . Fullerenes and nanotubes - Higher tier Like other substances that have giant molecular structures, fullerenes have high melting points and boiling points. Nanotubes have a massive surface area for their size. Spreading a catalyst, atom by atom, on the surface of a nanotube provides a huge surface area of catalyst for reactants to come into contact. Now try a Test Bite - higher tier. Page: Carbon, Chemical Element - structure, reaction, water, uses, elements, proteins, metal, gas PRONUNCIATION CAR-bun Carbon is such an important element that an entirely separate field of chemistry is devoted to this element and its compounds. Organic chemistry is the study of carbon compounds. Discovery and naming Humans have been aware of carbon since the earliest of times. When cave people made a fire, they saw smoke form. The black color of smoke is caused by unburned specks of carbon. The smoke may have collected on the ceiling of their caves as soot. Later, when lamps were invented, people used oil as a fuel.

When oil burns, carbon is released in the reaction, forming a sooty covering on the inside of the lamp. That form of carbon became known as lampblack. Lampblack was also often mixed with olive oil or balsam gum to make ink. And ancient Egyptians sometimes used lampblack as eyeliner. One of the most common forms of carbon is charcoal. Charcoal is made by heating wood in the absence of air so it does not catch fire. Instead, it gives off water vapor, leaving pure carbon. This method for producing charcoal was known as early as the Roman civilization (509 B.C.-A.D. 476). French physicist René Antoine Ferchault Reaumur (1683-1757) believed carbon might be an element. He studied the differences between wrought iron, cast iron, and steel. The main difference among these materials, he said, was the presence of a "black combustible material" that he knew was present in charcoal. Carbon was officially classified as an element near the end of the eighteenth century. In 1787, four French chemists wrote a book outlining a method for naming chemical substances.

The name they used, carbone, is based on the earlier Latin term for charcoal, charbon. Coal, soot (nearly pure carbon), and diamonds are all nearly pure forms of carbon. Physical properties Carbon exists in a number of allotropic forms. Allotropes are forms of an element with different physical and chemical properties. Two allotropes of carbon have crystalline structures: diamond and graphite. In a crystalline material, atoms are arranged in a neat orderly pattern. Graphite is found in pencil "lead" and ball-bearing lubricants. Among the non-crystalline allotropes of carbon are coal, lampblack, charcoal, carbon black, and coke. Carbon black is similar to soot. Coke is nearly pure carbon formed when coal is heated in the absence of air. Carbon allotropes that lack crystalline structure are amorphous, or without crystalline shape. The allotropes of carbon have very different chemical and physical properties. For example, diamond is the hardest natural substance known. It has a rating of 10 on the Mohs scale. The Mohs scale is a way of expressing the hardness of a material.

It runs from 0 (for talc) to 10 (for diamond). The melting point of diamond is about 3,700°C (6,700°F) and its boiling point is about 4,200°C (7,600°F). Its density is 3.50 grams per cubic centimeter. On the other hand, graphite is a very soft material. It is often used as the "lead" in lead pencils. It has a hardness of 2.0 to 2.5 on the Mohs scale. Graphite does not melt when heated, but sublimes at about 3,650°C (6.600°F). Sublimination is the process by which a solid changes directly to a gas when heated, without first changing to a liquid. Its density is about 1.5 to 1.8 grams per cubic centimeter. The numerical value for these properties varies depending on where the graphite originates. The amorphous forms of carbon, like other non-crystalline materials, do not have clear-cut melting and boiling points. Their densities vary depending on where they originate.

Chemical properties Carbon does not dissolve in or react with water, acids, or most other materials. It does, however, react with oxygen. It burns in air to produce carbon dioxide (CO 2 ) and carbon monoxide (CO). The combustion (burning) of coal gave rise to the Industrial Revolution (1700-1900). Another highly important and very unusual property of carbon is its ability to form long chains. It is not unusual for two atoms of an element to combine with each other. Oxygen (O 2 ), nitrogen (N 2 ), hydrogen (H 2 ), chlorine (Cl 2 ), and bromine (Br 2 ) are a few of the elements that can do this. Some elements can make even longer strings of atoms. Rings of six and eight sulfur atoms (S 6 and S 8 ), for example, are not unusual. Carbon has the ability to make virtually endless strings of atoms. If one could look at a molecule of almost any plastic, for example, a long chain of carbon atoms attached to each other (and to other atoms as well) would be evident. Carbon chains can be even more complicated. Some chains have side chains hanging off them.

Arrangement of carbon atoms in a diamond. There is almost no limit to the size and shape of molecules that can be made with carbon atoms. (See accompanying diagrams.) Buckyballs are a recently discovered form of pure carbon. These spheres are made up of exactly 60 linked carbon atoms. Occurrence in nature Carbon is the sixth most common element in the universe and the fourth most common element in the solar system. It is the second most common element in the human body after oxygen. About 18 percent of a person's body weight is due to carbon. The black color of smoke is caused by unburned specks of carbon. Carbon is the 17th most common element in the Earth's crust. Its abundance has been estimated to be between 180 and 270 parts per million. It rarely occurs as a diamond or graphite. Carbon reacts with oxygen by burning in air. Both allotropes are formed in the earth over millions of years, when dead plant materials are squeezed together at very high temperatures. Diamonds are usually found hundreds or thousands of feet beneath the earth's surface. Africa has many diamond mines. Carbon also occurs in a number of minerals.

Among the most common of these minerals are the carbonates of calcium (CaCO 3 ) and magnesium (MgCO 3 ). Carbon also occurs in the form of carbon dioxide (CO 2 ) in the atmosphere. Carbon dioxide makes up only a small part of the atmosphere (about 300 parts per million), but it is a crucial gas. Plants use carbon dioxide in the atmosphere in the process of photosynthesis. Photosynthesis is the process by which plants convert carbon dioxide and water to carbohydrates (starches and sugars). This process is the source of life on Earth. Carbon also occurs in coal, oil, and natural gas. These materials are often known as fossil fuels. They get that name because of the way they were formed. They are the remains of plants and animals that lived millions of years ago. When they died, they fell into water or were trapped in mud. Over millions of years, they slowly decayed. The products of that decay process were coal, oil, and natural gas. Some forms of coal are nearly pure carbon. Oil and natural gas are made primarily of hydrocarbons, which are compounds made of carbon and hydrogen.

Isotopes Three isotopes of carbon occur in nature, carbon-12, carbon-13, and carbon-14. One of these isotopes, carbon-14, is radioactive. Isotopes are two or more forms of an element. Isotopes differ from each other according to their mass number. The number written to the right of the element's name is the mass number. The mass number represents the number of protons plus neutrons in the nucleus of an atom of the element. The number of protons determines the element, but the number of neutrons in the atom of any one element can vary. Each variation is an isotope. Five artificial radioactive isotopes of carbon are known also. A radioactive isotope is one that breaks apart and gives off some form of radiation. Artificial radioactive isotopes can be made by firing very small particles (such as protons) at atoms. These particles stick in the atoms and make them radioactive. Carbon-14 has some limited applications in industry. For example, it can be used to measure the thickness of objects, such as sheets of steel. The steel must always be the same thickness.

Carbon is the sixth most common element in the universe and the fourth most common element in the solar system. In this process, a small sample of carbon-14 is placed above the conveyor belt carrying the steel sheet. A detection device is placed below the sheet. The detection device counts the amount of radiation passing through the sheet. If the sheet gets thicker, Less radiation gets through. If the sheet gets thinner, more radiation gets through. The detector records how much radiation passes through the sheet. If the amount becomes too high or too low, the conveyor belt is turned off. The machine making the sheet is adjusted to produce steel of the correct thickness. The most important use of carbon-14 is in finding the age of old objects (see accompanying sidebar for more information). Extraction Diamond, graphite, and other forms of carbon are taken directly from mines in the earth. Diamond and graphite can also be made in laboratories. Synthetic diamonds, for example, are made by placing pure carbon under very high pressures (about 800,000 pounds per square inch) and temperatures (about 2,700°C). The carbon is heated and squeezed in the same way organic material is heated and squeezed in the earth.

Today, about a third of all diamonds used are synthetically produced. Carbon-14 dating W hen an organism is alive, it takes in carbon dioxide from the air around it. Most of that carbon dioxide is made of carbon-12, but a tiny portion consists of carbon-14. So the living organism always contains a very small amount of radioactive carbon, carbon-14. A detector next to the living organism would record radiation given off by the carbon-14 in the organism. When the organism dies, it no longer takes in carbon dioxide. No new carbon-14 is added, and the old carbon-14 slowly decays into nitrogen. The amount of carbon-14 slowly decreases as time goes on. Over time, less and less radiation from carbon-14 is produced. The amount of carbon-14 radiation detected for an organism is a measure, therefore, of how long the organism has been dead. This method of determining the age of an organism is called carbon-14 dating. The decay of carbon-14 allows archaeologists (people who study old civilizations) to find the age of once-living materials. Measuring the amount of radiation remaining indicates the approximate age.

Uses There are many uses for carbon's two key allotropes, diamond and graphite. Diamonds are one of the most beautiful and expensive gemstones in the world. But they also have many industrial uses. Because they are so hard they are used to polish, grind, and cut glass, metals, and other materials. The bit on an oil-drilling machine may be made of diamonds. The tool used to make thin tungsten wires is also made of diamonds. Synthetic diamonds are more commonly used in industry than in jewelry. Industrial diamonds do not have to be free of flaws, as do jewelry diamonds. Graphite works well as pencil lead because it rubs off easily. It is also used as a lubricant. Graphite is added to the space between machine parts that rub against each other. The graphite allows the parts to slide over each other smoothly. Graphite is also used as a refractory. Refractory material can withstand very high temperatures by reflecting heat away from itself. Refractory materials are used to line ovens used to maintain high temperatures. Graphite is used in nuclear power plants. A nuclear power plant converts nuclear energy to electrical power. Graphite acts as a moderator by slowing down the neutrons used in the nuclear reaction.

Graphite is used to make black paint, in explosives and matches, and in certain kinds of cathode ray tubes, like the ones used in television sets. Amorphous forms of carbon have many uses. These include the black color in inks, pigments (paints), rubber tires, stove polish, typewriter ribbons, and phonograph records. One form of carbon is known as activated charcoal. The term activated means that the charcoal has been ground into a very fine powder. In this form, charcoal can remove impurities from liquids that pass through. For example, activated charcoal removes color and odor from oils and water solutions. The decay of carbon-14 allows archaeologists (people who study old civilizations) to find the age of once-living materials. Compounds Carbon dioxide (CO 2 ) is used to make carbonated beverages (it's the fizz in soda pop and beer), in fire extinguishers, and as a propellant in aerosol products. A propellant is a gas that pushes liquids out of a spray can, such as those used for deodorant or hair spray. Carbon dioxide can also be frozen to a solid called dry ice. It is widely used as a way of keeping objects cold.

Solid carbon dioxide is most commonly known as dry ice. Carbon monoxide (CO) is another compound formed between carbon and oxygen. Carbon monoxide is a very toxic gas produced when something burns in a limited amount of air. Carbon monoxide is always formed when gasoline burns in the engine of an automobile and is a common part of air pollution. Old heating units can produce carbon monoxide. This colorless and odorless gas can cause headaches, illness, coma, or even death. Carbon monoxide has a few important industrial uses. It is often used to obtain a pure metal from the ore of that metal: It would take a very large book to describe all the uses of organic compounds, which are divided into a number of families. An organic family is a group of organic compounds with similar structures and properties. The largest organic family is the hydrocarbons, compounds that contain only carbon and hydrogen. Methane, or natural gas (CH 4 ), ethane (C 2 H 6 ), propane (C 3 H 8 ), ethylene (C 2 H 4 ), and benzene (C 6 H 6 ) are all hydrocarbons. Hydrocarbons are used as fuels.

Gas stoves burn natural gas, which is mostly methane. Propane gas is a popular camping fuel, used in small stoves and lanterns. Another important use of hydrocarbons is in the production of more complicated organic compounds. Buckyballs and nanotubes In the 1980s, chemists discovered a new allotrope of carbon. The carbon atoms in this allotrope are arranged in a sphere-like form of 60 atoms. The form resembles a building invented by American architect Buckminster Fuller (1895-1983). The building is known as a geodesic dome. Each of the points on the dome is occupied by one carbon atom. The discoverers named the new form of carbon buckminsterfullerene in honor of Fuller. That name is too long to use in everyday conversation so it is usually shortened to fullerene or buckyball. The discovery of the fullerene molecule was very exciting to chemists. They had never seen a molecule like it. They have been studying ways of working with this molecule. One interesting technique has been to cut open just one small part of the molecule. Then they cut open a small part on a second molecule.

Finally, they join the two buckyballs together. They get a double-buckyball. Repeating this process over and over could result in triple-buckyballs, quadruple-buckyballs, and so on. As this process is repeated, the buckyball becomes a long narrow tube called a nanotube. Nanotubes are long, thin, and extremely tiny tubes somewhat like a drinking straw or a long piece of spaghetti. Scientists are beginning to find ways of using nanotubes. One idea is to run a thin chain of metal atoms through the center of a nanotube. This allows it to act like a tiny electrical wire. Nanotubes may completely change many devices that will be made in the future. Other organic families contain carbon, hydrogen, and oxygen. Methyl alcohol (wood alcohol) and ethyl alcohol (grain alcohol) are the most common members of the alcohol family. Methyl alcohol is used to make other organic compounds and as a solvent (a substance that dissolves other substances). Ethyl alcohol is used for many of the same purposes. It is also the alcohol found in beer, wine, and hard liquor, such as whiskey and vodka.

All alcohols are poisonous but some alcohols are more poisonous than others. If not drunk in moderation, alcoholic beverages can damage the body and brain. And, if drunk in large quantities, they can cause death. Methyl alcohol is more toxic than ethyl alcohol. People who have drunk methyl alcohol by mistake have died. The list of everyday products made from organic compounds is very long. It includes drugs, artificial fibers, dyes, artificial colors and flavors, food additives, cosmetics, plastics of all kinds, detergents, synthetic rubber, adhesives, antifreeze, pesticides and herbicides, synthetic fuels, and refrigerants. Health effects Carbon is essential to life. Nearly every molecule in a living organism contains carbon. The study of carbon compounds that occur in living organisms is called biochemistry (bio- = life + -chemistry ). Carbon can also have harmful effects on organisms. For example, coal miners sometimes develop a disease known as black lung. The name comes from the appearance of the miner's lungs. Instead of being pink and healthy, the miner's lungs are black. The black color is caused by coal dust inhaled by the miner. The longer a miner works digging coal, the more the coal dust is inhaled.

That worker's lungs become more and more black. Color is not the problem with black lung disease however. The coal dust in the lungs blocks the tiny holes through which oxygen gets into the lungs. As more coal dust accumulates, more holes are plugged up, making it harder for the miner to breathe. Many miners eventually die from black lung disease because they lose the ability to breathe. Carbon is essential to life. Nearly every molecule in a living organism contains carbon. Carbon monoxide poisoning is another serious health problem. Carbon monoxide is formed whenever coal, oil, or natural gas bums. For example, the burning of gasoline in cars and trucks produces carbon monoxide. Today, almost every person in the United States inhales some carbon monoxide every day. Small amounts of carbon monoxide are not very dangerous. But larger amounts cause a variety of health problems. At low levels, carbon monoxide causes headaches, dizziness, nausea, and loss of balance. At higher levels, a person can lose consciousness. At even higher levels, carbon monoxide can cause death. Also read article about Carbon from Wikipedia User Contributions: Fullerenes: An Overview Introduction The 1996 Nobel Prize for Chemistry has been won by Harold W.

Kroto, Robert F. Curl and Richard E. Smalley for their discovery in 1985 of a new allotrope of carbon, in which the atoms are arranged in closed shells. The new form was found to have the structure of a truncated icosahedron, and was named Buckminsterfullerene, after the architect Buckminster Fuller who designed geodesic domes in the 1960's. Formerly, six crystalline forms of the element carbon were known, namely two kinds of graphite, two kinds of diamond, chaoit and carbon(VI). The latter two were discovered in 1968 and 1972. In 1990 physicists W. Krätschmer and D.R. Huffman for the first time produced isolable quantities of C60 by causing an arc between two graphite rods to burn in a helium atmosphere and extracting the carbon condensate so formed using an organic solvent. The way was thus open for studying the chemical properties of C60 and other carbon clusters such as C70, C76, C78 and C84. New substances were produced from these compounds, with new and unexpected properties.

An entirely new branch of chemistry developed, with consequences in such diverse areas as astrochemistry, superconductivity and materials chemistry/physics. Professor Sir Harold W. Kroto (University of Sussex) 1. Structure and physical properties of higher fullerenes pp.2-5 2. Production of fullerenes pp.6-8 3. Chemistry of fullerenes pp.8-10 1.) Structures and Physical Properties of Some Higher Fullerenes Fullerenes consist of 20 hexagonal and 12 pentagonal rings as the basis of an icosohedral symmetry closed cage structure. Each carbon atom is bonded to three others and is sp2 hybridised. The C60 molecule has two bond lengths - the 6:6 ring bonds can be considered "double bonds" and are shorter than the 6:5 bonds.C60 is not "superaromatic" as it tends to avoid double bonds in the pentagonal rings, resulting in poor electron delocalisation. As a result, C60 behaves like an electron deficient alkene, and reacts readily with electron rich species. The geodesic and electronic bonding factors in the structure account for the stability of the molecule.

In theory, an infinite number of fullerenes can exist, their structure based on pentagonal and hexagonal rings, constructed according to rules for making icosahedra. The structure of C60: "Buckminsterfullerene" The infra red spectrum of C60(left); 13C NMR spectrum of C60 (right): C60 only has four IR active vibrational bands, due to its icosohedral symmetry. The UV/visual spectrum chromatographically purified C60 (left); A mass spectrum showing the higher fullerenes present in carbon soot (right): Mass spectrometry has been widely used to study the fullerenes. There is evidence for species as small as C20+, as well as stable peaks for the cluster ions C2n+ (where 2n>32).

Infra red spectrum of C70 (left); UV/visual spectrum of C70 (right): Carbon 13 NMR spectrum of C70: C76 "Buckytubes" & "Buckyonions" Many fullerenes have now been discovered in carbon soot, uncovered by electron microscopy, including tubes of carbon many thousands of times long as they are wide, with the same icosahedral structure as the fullerenes. These have diameters as small as 2nm. Carbon "onions" have also been discovered, and consist of carbon cages one inside the other rather like Russian dolls. These carbon particles have millions of atoms, and many have been observed with dozens of concentric shells. Hypothetical structures have been postulated for carbon cages consisting of not pentagonal and hexagonal rings (like C60), but heptagonal (7 membered) rings. A helically coiled carbon nanotube Atomic resolution picture of a single walled carbon nanotube taken using ascanning tunneling microscope. 2.) The Production of Fullerenes The first method of production of fullerenes used laser vaporization of carbon in an inert atmosphere, but this produced microscopic amounts of fullerenes.

In 1990, a new type of apparatus using an arc to vaporize graphite was developed in Germany by Kratschmer and Huffmann. Adapted Kratcshmer-Huffmann apparatus as used at Widener University Method for fullerene synthesis Pump down the system and introduce Helium gas into the chamber. Repeat (purge). Finally fill the bell-jar with about 100 Torr of Helium. Connect up the welding kit power supply Turn the on / off switch on the supply to the on position for 10 to 15 seconds. Afterwards there should be plenty of black soot like material produced inside the bell-jar. After a 5-10 min cool down period fill the bell-jar to atmospheric pressure. Take the bell-jar off and scrape the glass surfaces clean, collect all the material. 10 % of the soot should be made up of C60. The fullerenes in the soot are then extracted by solvation in a small amount of toluene. After extraction, the solvent (toluene) is removed using a rotary evaporator, leaving behind a solid mixture of mostly C60 with small amounts of larger fullerenes.

Pure C60 is obtained by liquid chromatography. The mixture is dissolved in toluene and pumped through a column of activated charcoal mixed with silica gel. The magenta C60 comes off first, followed by the red C70. The different color solutions are collected separately and the toluene removed using the rotary evaporator. A Mechanism for Fullerene Formation Although many mechanisms have been described, only the "pentagon road" appears to explain high yields of C60. This is described below, in an extract taken from an address by Professor Richard Smalley to the Robert A. Welch Foundation 39th Conference on Chemical Research: Nanophase Chemistry: Self-Assembly of Fullerene Tubes and Balls. "At the moment there is only one mechanism that appears to be consistent with yields of C60 as high as 30-40%. It is known as the Pentagon Road.

In this view, the yield is high because clustering continues in a hot enough region to permit the growing clusters to anneal to the minimum energy path: one where the graphene sheet (a) is made up solely of pentagons and hexagons, (b) has as many pentagons as possible, while (c) avoiding structures where two pentagons are adjacent. If the pentagon rule structures really are the lowest energy forms for any open carbon network, then one can readily imagine that high-yield synthesis of C60 may be possible. In principal, all one needs to do is adjust the conditions of the carbon cluster growth such that each open cluster has ample time to anneal into its favored pentagon rule structure before it grows further. This path through the kinetics is the Pentagon Road, and constitutes a mechanism of graphene-sheet self-assembly that leads to C60 in very high yield. The Pentagon Road must be the path that is followed in the high yield conditions.

This requires that the cluster growth temperature be high enough to anneal the open structures as they grow so that they follow the pentagon road, but that the temperature not be so high as to permit the extensive rearrangement and mounting of high activation barriers necessary to convert the open pentagon road structure to the closed fullerene. In the Krätschmer-Huffman (KH) experiment, carbon radicals are produced simply by slow evaporation of the surface of a resistively heated graphite rod. Here the carbon vapor density is far lower than that in pulsed laser vaporization, thus so too is the rate of clustering. Most critically, the rate of cooling of the condensing carbon vapor is much slower in the KH method. By adjusting the pressure of helium buffer gas around the evaporating graphite rods, one has at least coarse control over this rate of cooling and the clustering rate. At too low a pressure the carbon radicals migrate far away from the hot region around the resistively-heated rod and are too cold when they grow to the region of C60. But with just the right pressure of helium, the clustering in the critical size range occurs at just the right distance from the hot source that the temperature is optimal for the growing clusters to follow the Pentagon Road.

After the KH method was introduced, it was found at Rice that a simple ac or dc arc would produce C60 and the other fullerenes in good yield as well, and this is now the method used commercially. Even though the vaporization mechanism of a carbon arc differs markedly from that of a resistively heated carbon rod (because it involves a plasma) the optimum helium pressure for C60 formation is found to be very similar in each case. It is not so much the vaporization method that matters, but rather the conditions prevailing while the carbon vapor condenses. By adjusting the helium buffer gas pressure, one controls the rate of migration of the carbon vapor away from the hot graphite rod and thereby controls (at least crudely) the effective temperature and carbon radical density in the region where clusters in the size range near C60 are formed. The Pentagon Road mechanism is just one of many by which fullerenes can form, but it may be the only one capable of accounting for the single most telling fact of fullerene formation: that the overall C60 yield can be as high as 40% of all the carbon vaporized.

The Pentagon Road explains this as a consequence of annealing the open graphene sheets to their optimal open structure (given by the Pentagon Rule) at a rate faster than their growth, while avoiding rearrangement to a closed fullerene prior to the size of C60. It is a case of picking the reaction conditions to favor a particular product." Commercial production of Fullerenes The world's first computer controlled fullerene production plant is now operational at the MER corporation, who pioneered the first commercial production of fullerene and fullerene products. Commercial uses of fullerenes Although fullerenes are not yet used commercially, applications are being researched, such as catalytic methane activation to higher hydrocarbons funded by the US Dept of Energy. Other properties of fullerenes and their compounds such as superconductivity have yet to be exploited. 3.) Chemistry of the Fullerenes The reactions and reaction types of the fullerenes described below are merely examples of some recent work, not an exhaustive study. Redox chemistry C60 and C70 have similar properties, with six reversible one electron reductions to C60(6-) and C70(6-) having been observed. Oxidation of C60 and C70 is, however irreversible.

The first reduction for both fullerenes is ~1.0V for (Fc/Fc+), indicating they have electron accepting properties. C76 exhibits both electron donor/acceptor properties. C60 is an "alkene" C60 has a tendency of avoiding having double bonds within the pentagonal rings which makes electron delocalisation poor, and results in the fact that C60 is not "superaromatic". C60 behaves very much like an electron deficient alkene and readily reacts with electron rich species (see its organometallic reactions), but can also sometimes behave in a similar way to aromatic rings. Classes of fullerene compunds Compounds of fullerenes may be classed according to two different catagories: Exohedral (inside the cage) and Endohedral (outside the cage). Examples of the former include metals such as La enclosed in a C82 cage, and examples of the latter include transition metal complexes eg with Ir, as well as purely organic fragments bonded to the fullerene cage.

Fully brominated C60: C60Br(24) As noted above, fullerenes behave as electron deficient alkenes, and will react with electron rich species, such as halogens. Formation of C60Br24 by reactio of solid C60 with neat liquid bromine takes 5-8 days, but recently (Sept. 1996) a new method has been developed at Widener University, which reduces the reaction time to about an hour. Experimental : C60 (50mg) is placed in a closed conatiner with neat liquid bromine (5ml) and large gauge iron wire (ca. 1g), and stirred at room temp. for 1h. The excess liq. Br is then removed by vacuum evaporation, and the resulting solid treated with methanol to remove FeBr3 formed during the reaction. The remaining solid is then filtered and washed with methanol. Mechanism: The mechanism is thought to be similar to that of electrophilic aromatic substiution, i.e. the in-situ formation of FeBr3, (a Lewis acid) catalyzes the reaction by polarizing the Br2 molecule for electrophilic attack.

C60Br24 (ref. HADSIO) Endohedral Compounds When C60 was first discovered, new experiments were rapidly devised to test the C60 (as a closed cage structure) hypothesis. As the C60 structure is hollow, with room for one or more other atoms, attempts were made to enclose a metal atom. A graphite sheet was soaked with a solution of a metal salt (lanthanum chloride, LaCl3) and subjected to vaporisation-condensation experiments. Mass spectroscopic analysis of the clusters formed showed the presence of C60La+. These proved to be photoresistant, reinforcing the idea that metal atoms were "captured" inside the cage structure. The so called "shrink wrapping" experiment was then devised whereby ions of one size (or similar size) were captured in a magnetic trap and subjected to a laser pulse. The laser pulse causes the carbon cage to shrink by 2 carbon atoms at a time, until fragmentation ceased when pressure on the trapped metal atom is too big. The carbon cage now fits exactly around the metal atom.

For example, (forC60Cs+) this size is at (C48Cs+) and for (C60K+) it is at (C44K+). Below is an example of an endohedral metal fulleride, similar to that described above: La@C82 This field of fullerene research is very active,as this recent abstract shows: "Encapsulation of one or more metal atoms inside fullerene cages (endohedral metallofullerenes) is one of the most exciting topics in the fullerene science, since it could give rise to new species or materials with novel properties which are unexpected for hollow fullerenes. Recent important progress is marked by the successful isolation and purification of Sc@C-82, Y@C-82, La@C-82, Gd@C-82, La-2@C-80, and Sc-2@C-84 in large quantities. It is an interesting challenge to disclose how the properties of hollow fullerenes are modified upon endohedral metal-doping.

Recently, we have clarified the electronic structures and properties of endohedral metallofullerenes based on the theoretical calculations and have undertaken the first exohedral functionalization of metallofullerenes with organosilicon compound which can act as a mechanistic probe to clarify the electronic and chemical character of fullerenes. These successful exohedral derivatizations of endohedral metallofullerenes should open the way to a variety of new chemical entities with novel properties, enriching the chemistry of metallofullerenes." - Akasaka, T et al Journal of Synthetic Chemistry Japan 1996, vol 54, no.7 Chemical of the Week -- Buckyballs BUCKYBALLS The discovery of a new form of a pure element is a rather rare occurrence, especially for a common element. Therefore, reports of such discoveries generate an unusual amount of excitement among scientists. An example is the 1985 discovery of a new allotropic form of elemental carbon. The two well-known forms of elemental carbon are graphite and diamond. Both of these contain extended arrays of carbon atoms. In the new form, the carbon atoms are arranged in relatively small clusters of atoms.

In graphite, the carbon atoms are arranged in sheets with the bonds between the atoms forming hexagons, something like chicken wire. The sheets are only weakly bonded to each other, so they slide past one another, giving graphite a slippery feel and making it a good lubricant. Graphite is also used extensively in studies of the surface effects of energy in the form of light, heat, and electric current. When graphite is subjected to large bursts of energy of these sorts, portions of the top sheet of carbon atoms are ripped out. The ejected portions are studied to learn how the energy interacts with a solid surface. In the early 1980s, Harold W. Kroto of the University of Sussex in England was using microwave spectroscopy to analyze the composition of carbon-rich stars. The analysis indicated that the atmosphere of these stars contained cyanopolyynes, which are composed of chains of alternating carbon and nitrogen atoms. Prof. Kroto wanted to study how these chains could be formed. He contacted Robert F. Curl and Richard E. Smalley at Rice University in Texas because they had been using microwave spectroscopy to analyze clusters of metals formed in Prof. Smalley�s lab. Prof.

Smalley had an apparatus that could vaporize nearly any material into a plasma. In 1985, Kroto joined Curl and Smalley in Smalley�s lab to study the products of carbon vaporization. They fired a high-energy laser beam at a graphite surface and used a stream of helium gas to carry the fragments into a mass spectrometer. The mass spectrometer revealed the masses of the fragments of graphite ejected from the surface. These fragments varied from several atoms up to about 190 atoms. The distribution of fragments depended on the pressure of helium in the carrier stream. As the pressure increased from several torr to about 1 atm, the distribution of fragments changed, and the fragment containing sixty carbon atoms became by far the dominant one. Because the laser pulse and graphite surface had not changed, they reasoned that the fragments that broke off were not changing, but instead that the way these fragments interacted on their way into the mass spectrometer changed. At higher helium pressures, the fragments would be jostled together more than at lower pressures. This jostling leads to the formation of the most stable form of small carbon atom cluster, namely C60.

Kroto, Smalley, and Curl wondered how the atoms in this cluster were arranged to make it more stable than other clusters. They believed that its stability came from an arrangement in which all bonding capacity of the atoms is satisfied. In a small fragment of carbon-atom sheet ejected from a graphite surface, the atoms around the edge of the sheet would not be fully bonded. If, however, the sheet were to form into a ball so the edges would meet, the bonding capacity of all atoms would be satisfied. In thinking of how the atoms are arranged in this ball, the scientists considered the geodesic domes designed by the architect-engineer, R. Buckminster Fuller. These domes led them to suspect a structure of interlocking hexagons and pentagons, identical to those of a soccer ball. Because this idea was inspired by the geodesic dome, they named this C60 allotrope of carbon buckminsterfullerene. Buckminsterfullerene The amounts of buckminsterfullerene (�buckyballs,� for short) prepared by laser were extremely small. The evidence for the structure would remain sketchy until C60 could be prepared in larger quantities.

Such a preparation was discovered in 1990. In this method, a water-cooled cylinder contains a sharp graphite rod touching a graphite disk. The cylinder is evacuated to a pressure of 1 � 10-5 torr, and a current of 100 to 200 ampere is passed between the rod and the disk. This produces a soot that deposits on the walls of the cylinder. The soot is washed with toluene, producing a red-brown solution. When this solution is evaporated, it leaves a residue with a mass of about 10% of the original soot and containing more than 85% C60. With this method, about 1 gram of C60 can be produced in a day. A whole new chemistry has developed in which fullerene molecules are manipulated to form compounds. Because the C60 sphere is hollow, other atoms can be trapped within it. When a graphite sheet soaked in LaCl3 solution is subjected to vaporization-condensation experiments, a substance with formula LaC60 is formed. When other metal salts are used, the ball of carbon atoms can be shrunken with laser pulses to fit the metal ion within.

In this way, CsC48 and KC44 were formed. Other experiments have produced new materials with C60. For example, C60 doped with potassium is a superconductor below 18 Kelvin. In the C60 structure, other atoms have been substituted for the carbon atoms, producing derivatives such as C59N and C57B3. C60 has also been used to produce three-dimensional polymers. In addition, tubes of carbon atoms called nanotubes have also been made. In 1996, Harold Kroto, Richard Smalley, and Robert Curl shared the Nobel Prize in Chemistry for their discovery of buckminsterfullerene. Discovery of Fullerenes National Historic Chemical Landmark - American Chemical Society American Chemical Society Discovery of Fullerenes National Historic Chemical Landmark Designated October 11, 2010, at the Richard E. Smalley Institute for Nanoscale Science and Technology at Rice University in Houston, Texas. Landmark Lesson Plan: Discovery of Fullerenes Truncated icosahedron: technical term for a soccer ball in the United States, a football everywhere else.

The scientists who vaporized the graphite to produce C60 named the new carbon allotrope buckminsterfullerene (shortened to fullerenes or buckyballs) because the geodesic domes designed by inventor and architect Buckminster Fuller provided a clue to the molecule’s structure. Contents "The Discovery of Fullerenes" commemorative booklet produced by the National Historic Chemical Landmarks program of the American Chemical Society in 2010 (PDF). An Idea and a Machine Carbon, the basis of life, is one of the most common elements and one of the most studied; it comprises the whole discipline of organic chemistry. A study of pure carbon would not seem all that exciting to most chemists.

In 1984 Richard Smalley found himself less than thrilled when he received a request from Harry Kroto, a chemist at the University of Sussex, to use equipment in Smalley’s laboratory at Rice University to study a special kind of carbon molecule.1 “In retrospect,” Kroto writes, “…I seem to have been fascinated by various peculiar aspects of carbon chemistry for much of my research career.”2 Kroto wanted to investigate the origins of the long linear carbon chain molecules that he, together with Canadian radio astronomers, had discovered in interstellar space several years earlier. Kroto was convinced that these unusual, long flexible molecules had been created in the atmospheres of carbon-rich red giant stars and wanted to prove this contention using Smalley’s laser-supersonic cluster beam apparatus. This experiment also could be a preliminary pilot for a rather more complicated experiment that might solve a long-standing puzzle in astronomy—the carriers of the mysterious and now legendary diffuse interstellar bands.

The discovery of the fullerenes pushed pursuit of the carbon chain interstellar band project out of further consideration, but others have pursued it, so far without positive results.3 Clusters of any element can be studied in the AP2 (pronounced app-two), the colloquial name of Smalley’s machine. Operators fire an intense laser pulse at a target, which creates a hot vapor above it. The laser generates temperatures reaching tens of thousands of degrees, hotter than the surfaces of most stars. As the vapor cools, the evaporated atoms align in clusters. A high pressure burst of gas sweeps the vapor through the machine into a vacuum chamber, where clusters begin to condense as the vapor cools. A second laser pulse ionizes the clusters, pushing them into a mass spectrometer, where the clusters are analyzed.4 Buckminster Fuller’s Biosphere – U.S. Pavilion at the 1967 World Exposition in Montreal. Discovery of Fullerenes In 1984, Kroto met Robert Curl, an old friend, at a conference in Austin, Texas. Curl told Kroto about his collaboration with Smalley in studying atom clusters in Smalley’s machine.

Kroto was intrigued, and he accompanied Curl back to Houston, where he examined the machine and immediately saw the possibility of putting carbon in it to explore his theory about the formation of carbon chains in the atmosphere of stars.5 Smalley was less intrigued. He and Curl were busy studying semiconductor clusters and he declined initially to free up time on the apparatus.6 Kroto’s disappointment grew when he learned that a team of scientists at the Exxon Corporate Research Science Laboratory in Annandale, New Jersey, had performed experiments using lasers to vaporize graphite to form carbon clusters. The Exxon scientists, Eric Rohlfing, Donald Cox, and Andrew Caldor, had used a machine, similar to the AP2, built by Smalley’s group at Rice. The Exxon team found that carbon clusters of more than forty atoms tended to be an even number for some reason. “Because we were trying to avoid needless overlap and competition with the Exxon group,” Smalley wrote, “their steady progress in the field was yet another disincentive to taking up work on carbon clusters at Rice.”7 Despite the Exxon work, Smalley relented a year later and agreed to let Kroto use the cluster beam apparatus.

Curl telephoned to ask whether Kroto wanted the Rice team to carry out the experiment and send him the data or if wanted to come to Houston. Kroto says “one thing was certain in my mind: I had not waited this long to have my experiments carried out by others...”8 He “pinched” money from his wife, packed his bags, and arrived in Houston a few days later, in late August.9 Kroto, Smalley, and Curl conducted the study, with the assistance of three graduate students, James Heath, Sean O’Brien, and Yuan Liu. On August 23, before Kroto’s arrival, Smalley had the students load carbon in the apparatus as a test of the new experiments.10 On September 1, four days after Kroto landed in Houston, the experiments began in earnest. The students ran the machine with Kroto directing the experiments. Two significant results emerged from the feverish ten days of experiments: first, the team found, as Smalley put it, “Kroto’s long carbon snakes”; second, the scientists also observed, again according to Smalley, “a previously unknown molecule of pure carbon.”11 The lab book for September 2 first notes the unknown molecule.

Then on Wednesday, September 4, using helium as the carrier gas, the students noticed, in Kroto’s words, “something quite remarkable… taking place,” an odd peak in the mass spectroscopy measurement of the molecules that formed in the vapor.12 The peak occurred at sixty carbon atoms (a smaller peak also occurred at seventy atoms). Yuan Liu noted in the lab book, “C60 and C70 are very strong,” adding an exclamation mark and underlining the entry.13 From the beginning of the experiments, the team met regularly to analyze the data. Now the scientists focused the discussions on the mystery of C60. At first, the group referred to it as a wadge, a British term for “a handful of stuff,” with Smalley referring to the mother wadge, Kroto to the godwadge.14 The Fullerene Discovery Team in front of the Space Science Building at Rice University. Shown from left to right: Sean O’Brien, Richard Smalley, Robert Curl, Harry Kroto and James Heath. Courtesy Richard E. Smalley Institute for Nanoscience and Technology at Rice University.

Determining the Structure of Fullerenes Since Kroto was scheduled to return to England early the following week, Heath and O’Brien spent the weekend trying to plumb the mystery molecule’s properties. One thing became apparent: C60 formed very readily and exhibited extraordinary stability; in one instance, AP2 produced forty times more C60 than either C58 or C62 carbon clusters.15 What was the structure of these clusters? The scientists were stumped at first by the stable, sixty-carbon molecule that did not react with other molecules, which suggested it had no dangling bonds. All known carbon-containing molecules, even benzene, a very stable ring of carbon atoms, have edges that terminate with other elements. But C60 was chemically inert; it did not need hydrogen, or any other element, to tie up its bonds.16 The team considered two candidates for C60’s structure: a so-called flatlander model where carbon was stacked in hexagonal sheets, similar to the structure of graphite, with the dangling bonds tied up in some fashion; or a spherical form where the hexagonal graphite sheet curled around and closed.

A closed structure, a cage, would have no dangling bonds.17 None of the scientists on the team remembers who first suggested a caged structure. Kroto and Smalley later disagreed on which one of them pushed the idea at first and who came up with the eventual name for C60. As for the name, buckminsterfullerene, Curl only says, “Harry was convinced that was his idea and Rick was convinced it was his idea and I'm convinced it wasn't my idea."18 Monday, September 9 was climactic. Spheroids dominated the discussion. At some point during the previous week Buckminster Fuller and his geodesic domes had been raised. Kroto and Smalley thought hexagons made up the surface of geodesic domes. Then Kroto remembered a stardome he once made for his children; he told Smalley it had pentagonal facets as well as hexagonal ones, but he was unsure. Besides, it was hidden in a closet at home in England.

Kroto also remembered visiting Fuller’s famous geodesic dome at Expo 67 in Montreal.19 At one point, the team viewed a photograph of one of the architect’s domes, a shed for railroad rolling stock designed by Fuller for the Union Tank Car Company in Baton Rouge, Louisiana. The dome hugged the ground and looked like an overturned wok. The structure’s grid appeared to be entirely composed of hexagons. Curl, who brought a healthy dose of skepticism to the entire project, doubted whether hexagons alone would do the trick.20 With the daytime discussion seemingly reaching a dead end, part of the group went to a favorite Mexican restaurant to celebrate the discovery of C60.21 During the meal, Smalley wondered how a sheet of hexagons could close; perhaps, the only way to find out was to build one.22 Smalley worked into the night at his home computer trying to generate a structure. When that failed, he turned to low-tech tools: paper, tape, and scissors. He began by cutting out hexagons, about an inch on each side, from a pad of legal paper.

When he attached the hexagons he found that he had to cheat a bit to get the surface to curve. Eventually, he realized that even with cheating the hexagons would not close.23 “It was midnight,” Smalley writes, “but instead of going to bed I went to the kitchen for a beer.”24 While sipping his beer, Smalley remembered the stardome, Kroto mentioned he made using pentagons as well as hexagons. “I went back to my desk,” Smalley says, “cut a single pentagon from the legal paper and began sticking pentagons around it. Now no cheating was required. The hexagons automatically assumed the shape of a bowl.”25 He had discovered that by interspersing pentagons among the usual carbon hexagons (many carbon compounds have both five- and six-membered rings) the result would be a geodesic dome with sixty vertices. Smalley had stumbled through trial-and-error on a mathematical truth Fuller employed in his domes: a sheet of hexagons can be made to curl by using pentagons.26 Sixty, it turned out, was the only number of atoms that could form a nearly perfect sphere.

The next morning, on the way to Rice, Smalley called Curl, asking him to assemble the team in Smalley’s office. Kroto later wrote wrote that when Smalley tossed the paper model of twelve pentagons and twenty hexagons on a table in his office the next day, “I was ecstatic and overtaken with its beauty.”27 Smalley called a Bill Veech, chair of Rice’s mathematics department, to ask if he was familiar with the form. The answer came a few minutes later in a return call: “I could explain this to you in a number of ways, but what you’ve got there, boys, is a soccer ball.”28 Back to top Nobel Prizes and Nanotubes The Nature letter describing C60 was attractive and logical, but seeing a line in a mass spectrum did not convince all scientists of the discovery of a new allotrope of carbon. During the period 1985-1990, the Curl/Smalley team at Rice and Kroto at Sussex managed to amass a wide range of circumstantial evidence to support the fullerene structure proposal.

Full acceptance came when Wolfgang Krätschmer of the Max Planck Institute for Nuclear Physics in Heidelberg, Germany, and Donald Huffman of the University of Arizona, with their students Konstantinos Fostiropoulos and Lowell Lamb, succeeded in synthesizing C60 in sufficient quantities to allow structural characterization.29 In 1996 Smalley, Kroto, and Curl won the Nobel Prize in Chemistry. The presenter of the Nobel noted that the discovery of fullerenes has implications for all the natural sciences. It was born of astronomy, by the wish to grasp the behavior of carbon in red giant stars in interstellar gas clouds and by the work of Curl and Smalley in cluster chemistry at Rice University. It has expanded knowledge of chemistry and physics. Fullerenes have been found in geological formations and in sooty flames. Possible future uses include in antibiotics and as armor.30 Research on fullerenes has resulted in the synthesis of a steadily increasing number of new compounds, already more than one thousand. The discovery of fullerenes also led to research in carbon nanotubes, the cylindrical cousins of buckyballs, and the development of new fields of advanced materials.

Carbon nanotubes' unique structural and bonding properties, whereby inner tubes in a multi-walled nanotube can slide within an outer tube, suggest uses in tiny motors and as ball bearings and lubricants. Twenty-five years after their discovery, fullerenes provide abundant research opportunities in pure chemistry, materials science, pharmaceutical chemistry, and nanotechnology. Research Notes and Further Reading Research Notes Smalley wrote: “Thus to the modern chemist a continuing study of pure carbon would seem to offer little hope for excitement.” Richard Smalley, “Great Balls of Carbon: The Story of Buckminsterfullerene,” The Sciences (March/April 1991): 22. On the importance of carbon and its frequency of study, see Hugh Aldersey-Williams, The Most Beautiful Molecule: The Discovery of the Buckyball (New York: John Wiley & Sons, 1995), chapter 1. Harold Kroto, “Symmetry, Space, Stars and C60,” Nobel Lecture, December 7, 1996, p. 45, .

Harold Kroto, “C60: Buckminsterfullerene, The Celestial Sphere that Fell to Earth,” Angewandte Chemie 31:2 (February 1992): 114; Harold Kroto to Judah Ginsberg, July 30, 2010; Robert Curl to Judah Ginsberg, August 9, 2010. Aldersey-Williams, The Most Beautiful Molecule, pp. 56-58; Jim Baggott, Perfect Symmetry: The Accidental Discovery of Buckminsterfullerene (Oxford, UK: Oxford University Press, 1996), pp. 36-42; Robert Curl, Jr., “Dawn of the Fullerenes: Experiment and Conjecture, Nobel Lecture, December 7, 1996, pp. 12-14, ; Richard Smalley, Discovering the Fullerenes, Nobel Lecture, December 7, 1996, pp.

96-97, Smalley later wrote: “To test the theory he [Kroto] wanted to reproduce the stellar conditions in the laboratory, and he knew Rice had the machinery to prove it.” Smalley, “Great Balls of Carbon,” p. 22; Kroto describes his visit to Rice in 1984 in Kroto, “C60: Buckminsterfullerene,” p. 114. Baggott, Perfect Symmetry, p. 43. Smalley, “Great Balls of Carbon,” p. 23; see also, Baggott, Perfect Symmetry, pp. 43-47. Kroto, “C60: Buckminsterfullerene,” p. 115. Ibid.; Kroto says he “pinched” money from his wife in a lecture entitled “C60, the Celestial Sphere that Fell to Earth,” recorded in 1995. It can be found at . “AP2 Chronology 1985” (Rice University: unpublished, 1992).

Smalley and Heath prepared this document, in consultation with Curl and O’Brien, during May 2-5, 1992. Much of this is the reconstructed logbook, and I am indebted to Dr. Cyrus Mody of Rice University for supplying me with this and other documents. See also Aldersey-Williams, The Most Beautiful Molecule, p. 61. Smalley, “Great Balls of Carbon,” p. 22. Kroto, “C60: Buckminsterfullerene,” p. 115. In his lecture of the same name, Kroto describes September 4, 1985, as “C60’s Birthday.” . See “AP2 Chronology.” Also see Aldersey-Williams, The Most Beautiful Molecule, p. 66; Baggott, Perfect Symmetry, p. 55. Kroto, “C60: Buckminsterfullerene,” p. 116. Gary Taubes, “The Disputed Birth of Buckyballs,” Science 253 (1991): 1477.

Taubes quotes Kroto as describing “wadges” as a “peculiarly British expression for a featureless heap of junk.” Ibid. In an email to the author, Kroto defines it as “a handful of stuff.” Kroto to Ginsberg, July 30, 2010 Taubes, “The Disputed Birth of Buckyballs,” p. 1477; Aldersey-Williams, The Most Beautiful Molecule, p. 71. Taubes, “The Disputed Birth of Buckyballs,” p. 1477. Ibid. Robert Curl, Jr., series of interviews with Dr. Cyrus Mody, spring-summer, 2008. Thanks again to Dr. Mody for making this interview available. In the aftermath of the discovery of fullerenes, a dispute arose between Smalley and Kroto over two issues: The name of the molecule and its structure. See note 10 to chapter 2 in Aldersey-Williams, The Most Beautiful Molecule, P. 297-298 for a lengthy discussion of the issues involved.

For each participant’s views on the disputes, see Kroto, “C60: Buckminsterfullerene,” pp. 111-129 and Smalley, “Great Balls of Carbon,” pp. 22-28. Kroto discusses the stardome and visiting Expo 67 in “C60: Buckminsterfullerene,” pp. 116-117. Smalley writes: “[O]ne problem with the closed solution was that none of us was acquainted with the design principle embodied in geodesic domes.” Smalley, “Great Balls of Carbon,” p. 24. Aldersey-Williams, The Most Beautiful Molecule, p. 72. At dinner were Kroto, Smalley, Heath and Heath’s wife. O’Brien and Curl had other plans for the evening. Baggott, Perfect Symmetry, p. 67, Heath and his wife, Carmen, tried and failed that evening to build a geodesic dome out of Gummy Bears and toothpicks. See, Aldersey-Williams, The Most Beautiful Molecule, p. 73 Smalley, Great Balls of Carbon,” pp. 24-25.

See also, Aldersey-Williams, The Most Beautiful Molecule, p. 73 and Baggott, Perfect Symmetry, pp. 68-70. Smalley, Great Balls of Carbon,” p. 25. Ibid. Taubes, “The Dispute Birth of Buckyballs,” p. 1478. Kroto, “C60: Buckminsterfullerene,” p. 117. Smalley, Great Balls of Carbon,” p. 25. Aldersey-Williams, The Most Beautiful Molecule, pp. 195ff. Presentation Speech for 1996 Nobel Prize in Chemistry by Professor Lennart Eberson of the Royal Swedish Academy of Science, . Further Reading Back to top Concerning the question of what kind of 60-carbon atom structure might give rise to a superstable species, we suggest a truncated icosahedron, a polygon with 60 vertices and 32 faces, 12 of which are pentagonal and 20 hexagonal.” — From the abstract of a famous letter to Nature (Vol.

318, 14 November 1985) describing the dramatic discovery of the first known molecular form of carbon. Landmark Designation and Acknowledgments Landmark Designation The American Chemical Society designated the discovery of the fullerenes as a National Historic Chemical Landmark in a ceremony at the Richard E. Smalley Institute for Nanoscale Science and Technology at Rice University in Houston, Texas, on October 11, 2010. The text of the plaque commemorating the development reads: In this building in early September 1985, a team of scientists discovered a previously unknown pure carbon molecule, C60, which they dubbed buckminsterfullerene. The name was chosen because the geodesic domes of Buckminster Fuller provided a clue that the molecule’s atoms might be arranged in the form of a hollow cage. The structure, a truncated icosahedron with 32 faces, 12 pentagonal and 20 hexagonal, has the shape of a soccer ball.

Nicknamed buckyballs, this first known stable molecular form of carbon not only opened up a new field of organic chemistry but also, through the development of carbon nanotubes, a new field of materials science. In 1996, Robert Curl, Harold Kroto, and Richard Smalley won the Nobel Prize in Chemistry for the discovery of the fullerenes. Acknowledgments Adapted for the internet from “The Discovery of Fullerenes,” produced by the National Historic Chemical Landmarks program of the American Chemical Society in 2010. BBC - GCSE Bitesize: Carbon Next Nanochemistry works with materials at the atomic level and has many potential applications for medical science. The element carbon comes in different forms or 'allotropes' - three examples are diamond, graphite and Buckminster Fullerene. Their properties make them useful for different purposes. Carbon The allotropes of carbon Three forms (or 'allotropes') of pure carbon are diamond, graphite and buckminster fullerene (or 'buckyballs'). In all three allotropes the carbon atoms are joined by strong covalent bonds but in such different arrangements that the properties of the allotropes are very different.

Diamond Diamond A diamond is one giant molecule of carbon atoms. Diamonds are colourless and clear (transparent). They sparkle and reflect light – they're lustrous. These properties make them desirable in items of jewellery. Diamond is extremely hard and has a high melting point. For this reason it's very useful in cutting tools. The cutting edges of discs used to cut bricks and concrete are tipped with diamonds. Heavy-duty drill bits, like those used in the oil exploration industry to drill through rocks, are made with diamonds so that they stay sharp for longer. Diamond is insoluble in water. It does not conduct electricity. Higher tier Every atom in a diamond is bonded to its neighbours by four strong covalent bonds leaving no free electrons and no ions. That's why diamond does not conduct electricity. The bonding also explains the hardness of diamond and its high melting point. A lot of energy would be needed to separate atoms so strongly bonded together. Graphite Graphite Graphite is formed from carbon atoms in layers. Graphite is black, shiny and opaque (not transparent). It's also a very slippery material. It's used in pencil leads – it slips easily off the pencil onto the paper and leaves a black mark.

It's a component of many lubricants, for example bicycle chain oil. Graphite is insoluble in water. It has a high melting point and is a good conductor of electricity, which makes it a suitable material for the electrodes needed in electrolysis. Higher tier Each carbon atom is bonded into its layer with three strong covalent bonds. This leaves each atom with a spare electron, which together form a delocalised ‘sea’ of electrons loosely bonding the layers together. These delocalised electrons can all move along together – making graphite a good electrical conductor. Because the layers are only weakly held together they can easily slip over one another: hence the slipperiness of graphite. Melting graphite is not easy however. It takes a lot of energy to break the strong covalent bonds and separate the carbon atoms. Buckminster Fullerene Structure of a buckminsterfullerene molecule - a large ball of 60 atoms Buckminster Fullerene is one type of fullerene. Fullerenes are made from carbon atoms joined together to make balls, ‘cages’ or tubes of carbon. The molecules of Buckminster Fullerene are spherical and are also known as 'buckyballs' – formula C60.

Buckminster Fullerene is a black solid although it's deep red when in solution in petrol. The tube fullerenes are called nanotubes which are very strong and are conductors of electricity. Their unusual electrical properties mean that nanotubes are used as semiconductors in electronic circuits. Their strength makes them useful in reinforcing structures where exceptional lightness and strength are needed for example, the frame of a tennis racket. They're also used as a platform for industrial catalysts. Page: Are diamonds organic compounds? Why? - Quora Quora Diamonds are not organic compounds. Compounds are substances made up of two or more chemical elements. Instead, Diamonds are allotropes of the element Carbon. It is the tetrahedral formation of Carbon-12 atoms. Here's the basic structure of diamonds: Note that it is indeed all one element, which is Carbon (represented by dark spheres in the image) Written Jan 9, 2016 （abridged form Organic Chemistry , 6th edition, L.G. wade, Jr) The distinctive feature of organic compound is that they all contain one or more carbon atoms.

Still, not all carbon compounds are organic; substances such as diamond, graphite, carbon dioxide, ammonium cyanate, and sodium carbonate are derived from minerals and have typical inorganic properties. 817 Views The definitions of Inorganic compound and organic compound are not well defined. Diamond is one of the exceptions to the organics contain carbon definition. Another definition is that: Inorganic compounds are traditionally viewed as being synthesized by the agency of geological systems . In contrast, organic compounds are found in biological systems . Diamonds you will note are formed geologically so fit nicely in that category. CO2 also forms naturally without the biological systems so it is also considered inorganic. But it does have a very active role in biological systems and formed by biological systems. Hence the not well defined. Diamonds are NOT compounds at all. com·pound noun A thing that is composed of two or more separate elements; a mixture."the air smelled like a compound of diesel and gasoline fumes"synonyms: amalgam , amalgamation , combination , composite , blend , mixture , mix , fusion , synthesis ; alloy "a compound of two elements" adjective Made up or consisting of several parts or elements, in particular.

The chemical dictionary also goes on to say that there are at least *two* elements present in any compound; this clearly does not include allotropes of any element. 521 Views Written Feb 24, 2016 Diamonds are minerals, and minerals are by definition solid, crystalline, inorganic substances of uniform chemical composition. Thus diamonds are inorganic. Besides, diamonds are an allotrope, or form, of carbon. Pure elements are inorganic. If you thought diamonds might be organic because it contains carbon, organic chemistry does not encompass all carbon compounds. Carbon dioxide, for example, contains carbon, but it is not an organic compound. 404 Views

Question: Buckminster-Fullerene, made up of spheres of 60 atoms is an allotrope of which element?
Answer: Carbon