The Nobel Prize in Chemistry 1996

Sir Harold Kroto

The Discovery of Buckminsterfullerene - The Fullerenes

Carbon

Everyone knows that diamonds are sparkling gemstones, and that graphite is the 'lead' in pencils. What is little known, and at first rather strange, is that these vastly different materials are actually made up of the same atomic building blocks - carbon atoms (ie. they are allotropes).

Why are they so different ? The answer to this apparent contradiction was actually found almost a hundred years ago when scientists probed the materials with X-rays to determine their internal atomic structure. It turns out that the atoms in diamond are arranged in a rigid 3D structure, while the atoms in graphite are arranged in sheets of atoms. In graphite these sheets can move over each other fairly freely (see the picture over the page) but in diamond the atoms are held rigidly. Diamond is therefore hard while graphite is soft. Further analysis along these lines also explains why diamond is an insulator and crystal clear, while graphite is a conductor and opaque.

People have been using diamonds and graphite for thousands of years, proof of this comes from the names which are derived from the ancient Greek. Diamond means 'invincible' related to its hardness, the hardest naturally occurring material. Graphite means 'to write' obviously this name was applied to an early use of the substance and we still use graphite today in pencils. Diamond and graphite are most important industrial materials. Diamonds can be mounted on to drill bits to extend the working life of the tip and allow them to cut into extremely hard materials. Graphite is used extensively in the manufacture of motors, heating equipment and electronic components.

It is apparent that diamond and graphite are important materials. In fact the study of carbon materials is an extremely important area of research. The discovery of a third form of carbon would therefore caused a great stir in the scientific community if it were true. The brief story outlined below describes this new third form of carbon; buckminsterfullerene (more commonly called C60) and indeed it has caused an explosion of activity throughout science. Buckminsterfullerene is a tiny molecular cage of carbon having 60 atoms making up the mathematical shape called a truncated icosohedron. You actually know the shape of this structure very well because it happens to be the same shape as a football ! (12 pentagons and 20 hexagons count them). The experiments made during this workshop will allow you to make, analyse and purify C60 yourself.

Buckminsterfullerene - a strange name ? The round cage like structure of the fullerenes was reminiscent of the dome structures designed by the architect Richard Buckminster Fuller, and so C60 was named Buckminsterfullerene. These amazing buildings can cover large areas of land and the light weight and durable construction makes them ideal structures especially for building that have to withstand large changes in temperature and high winds such as found in the Arctic, for example. They also make good climbing frames and many small fuller type domes can be seen in playgrounds.

The discovery of microscopic amounts of Buckminsterfullerene

C60, buckminsterfullerene, and a whole family of carbon cage molecules called the fullerenes, were first discovered in 1985 on a very sensitive laboratory instrument. The amount of C60 actually being produced in the experiment was very small. The scientists calculated that, even if the machine was run for ten years non-stop it would barely produce enough C60 to line the bottom of a test tube (a few milligrams perhaps).

C60 was therefore initially discovered in microscopic amounts at levels too small to allow purification and analysis by any other techniques. However, from 1985 - 1990 the theoretical scientists started to calculate the physical and chemical properties of these curious molecules.

Making gram quantities of fullerenes

The next scientific breakthrough came in 1990 when a German / American group and the Sussex group independently showed that C60 could be made in gram quantities using a carbon arc. The technique is essentially very simple; if a voltage is applied to two carbon rods, (just touching), an arc will develop between them. If the arc is maintained in helium or argon (instead of in air) clouds of black smoky carbon soot are produced. It turns out that at the correct arc temperature and gas pressure up to 10 % of the black soot is C60. Also present in the soots are 1% C70, and smaller quantities of larger fullerenes.

The fullerenes are also found to be soluble in common solvents such as benzene, toluene or chloroform. If you shake up some of the fullerene soot with toluene and filter the mixture, one obtains a red solution. If you take a drop of this solution and place it under microscope, as the solvent evaporates, crystals of pure carbon appear in front of your eyes. These crystals are made up of millions and millions of tiny balls all packed together side by side and on top of each other. The beautiful pictures obtained using high power electron microscopes dramatically confirm this.

Fullerene Science

Now the world has a method to make these fascination new carbon molecule we have started to investigate their physical and chemical properties. With the development of this incredibly simple technique the field of fullerene research has grown at an alarming rate. There are now thousands of articles and scientific publications on the fullerenes and it looks as though the new field of fullerene science is here to stay.

Has carbon any other 'tricks up its sleeves' soon after the discovery that the fullerenes could be made in the carbon arc other interesting carbon structures were discovered lurking in the carbon soot. Electron microscopes have uncovered tiny carbon tubes ('buckytubes'), some having diameters as small as 2 nm or so, many are thousands of times as long as they are wide. Carbon 'onions' have also been found and these can be considered as carbon cages one inside the other, rather like a carbon version of the Russian doll toy. These carbon particles have many millions of atoms and some have been observed with dozens of concentric shells.

The tubes and onions are likely to be composed of hexagonal and pentagonal carbon rings just like the fullerenes. However it looks as if structures having heptagonal (7 member) rings may also be possible. One such hypothetical structure is shown on the second page of this booklet. These nanoscale fullerene based structures (fullerenes, tubes and onions) represent a new range of carbon materials - materials destined to play a role in the technology of the 21st century.

I was the kid with the funny name in my form. That is one of the earliest memories I have of school (except for being forced to finish school dinners). Other kids had typical Lancashire names such as Chadderton, Entwistle, Fairhurst, Higginbottom, Mottershead and Thistlethwaite though I must admit that there were the odd Smith, Jones and Brown. My name at that time was Krotoschiner (my father changed it to Kroto in 1955 so it is now occasionally thought, by some, to be Japanese). I felt as though I must have come from outer space - or maybe they did! I now realise that I had made a continual subconscious effort to blend as best I could into the environment by making my behaviour as identical as possible to that of the other kids. This was not easy indeed it was almost impossible with a couple of somewhat eccentric parents (in particular an extrovertly gregarious mother) who were born in Berlin and came to Britain as refugees in their late 30's.

Bolton is a once prosperous but then (the fifties) decaying northern English town which is rightfully proud of its legendary contributions to the industrial revolution - the likes of Samuel Crompton and Richard Arkwright were Boltonians. Indeed we lived in Arkwright St. and I shall always remember walking to school each morning past the windows of cotton mills through which I could see the vast rows of massive looms and spinning frames operated by women who had been working from at least six o'clock in the morning, if not earlier.

My efforts to merge into the background meant, among other things such as fighting (literally) for survival, speaking only English (all real Englishmen expect others to speak English) - though I allowed myself to absorb just enough German to understand what my parents were saying about me when they spoke German. One specific memory was that when I did particularly poorly at French one year my Father gave me a very large French dictionary for my birthday - was I pleased!!!

My name seems to have its origins in Silesia where my father's family originated and there is a town in Poland now called Krotoszyn (then Krotoschin). My father's family came from Bojanowo and set up a shop in Berlin where my father was born in 1900. The original family house, which was then a shop, still exists in the main square in Bojanowo. I have an old photograph which shows the sign "I. Krotoschiner" in gothic characters emblazened over the window. I visited the town recently and, apart from cars rather than horsedrawn carts and the sign, little has changed - the Hotel Centralny is now the Restauracja Centralny and the aerials on the roofs are still there!

My father, who originally wanted to be a dress designer but somehow ended up running a small business printing faces and other images on toy balloons, had to leave Berlin in 1937 and my mother (who was not Jewish) followed a few months later. I always felt that my parents had a really raw deal, as did almost everyone born in Europe at the turn of the Century. The First World War took place while they were teenagers, then the Depression struck and Hitler came to power while they were young adults. They had to leave their home country and then the Second World War broke out and they had to leave their home again. When my father was 45 he had to find a new profession, when he was 55 he set up his business again and when he was 65 he realised I was not going to take it over. He sold the business and retired in his early 70's.

I do not know how my father managed to catch the train to take him over the border into Holland in 1937. For as long as I knew him he was always late for everything; he invariably missed every train or bus he was supposed to catch. He told me that this was because he was called up in 1917 to go to the Front but arrived at the station just as the train was pulling out. When he asked the station master what he should do, he was told to go home. From then on he decided to make a point of missing trains and buses, but seems to have made one exception, in 1937. My parents managed to set up their small business again in London but the effort was, of course, shortlived due to the outbreak of the War in September 1939. I was born in Wisbech (a very small town in Cambridgeshire to which my mother was evacuated) on Oct 7th 1939 in the first month of the War so I was a war baby. My father was interned on the Isle of Man because he was considered to be an enemy alien; my mother (who was also an alien, but presumably assumed not to be an enemy one) was moved (with me - when I was about one year old) from London to Bolton in 1940. After the war my father became an apprentice engineer and because he was so good with his hands he managed to get a job as a fully qualified toolmaker at an engineering company in months rather than years.

In 1955, with help from friends in England and Germany from before the war, he set up his own small factory again, this time to make balloons as well as print them. I spent much of my school holidays working at the factory. I was called upon to fill in everywhere, from mixing latex dyes to repairing the machinery and replacing workers on the production line. I only now realise what an outstanding training ground this had been for the development of the problem solving skills needed by a research scientist. I am also sure that what I was doing then would contravene present-day health and safety at work regulations. I would have been considered too young and inexperienced to do the sort of maintenance work that I was often called upon to do. I did the stocktaking twice-a-year using a set of old scales with sets of individual gram weights (weighing balloons 10 at-a-time to obtain their average weights), my head, log tables and a sliderule to determine total numbers of various types of balloons. No paradise of microprocessor controlled balances then. After each stocktaking session I invariably felt that I never wanted to see another balloon as long as I lived.

My parents had lost almost everything and we lived in a very poor part of Bolton. However they did everything they could to get me the best education they could. As far as they were concerned this meant getting me into Bolton School, a school with exceptional facilities and teachers. As a consequence of misguided politically motivated educational policies this school has become an independent school and it bothers me that, were I today in the same financial position as my parents had been when I was a child, I would not be able to send my children to this school. Though I did not like exams or homework any more than other kids, I did like school and spent as much time as I could there. At first I particularly enjoyed art, geography, gymnastics and woodwork. At home I spent much of the time by myself in a large front room which was my private world. As time went by it filled up with junk and in particular I had a Meccano set with which I "played" endlessly. Meccano which was invented by Frank Hornby around 1900, is called Erector Set in the US. New toys (mainly Lego) have led to the extinction of Meccano and this has been a major disaster as far as the education of our young engineers and scientists is concerned. Lego is a technically trivial plaything and kids love it partly because it is so simple and partly because it is seductively coloured. However it is only a toy, whereas Meccano is a real engineering kit and it teaches one skill which I consider to be the most important that anyone can acquire: This is the sensitive touch needed to thread a nut on a bolt and tighten them with a screwdriver and spanner just enough that they stay locked, but not so tightly that the thread is stripped or they cannot be unscrewed. On those occasions (usually during a party at your house) when the handbasin tap is closed so tightly that you cannot turn it back on, you know the last person to use the washroom never had a Meccano set.

At no point do I ever remember taking religion very seriously or even feeling that the biblical stories were any different from fairy stories. Certainly none of it made any sense. By comparison the world in which I lived, though I might not always understand it in all aspects, always made a lot of sense. Nor did it make much sense that my friends were having a good time in a coffee bar on Saturday mornings while I was in schul singing in a language I could not understand. Once while my father and I were fasting, I remember my mother having some warm croissants - and did they smell good! I decided to have one too - ostensibly a heinous crime. I waited for a 10 ton "Monty Python" weight to fall on my head! It didn't. Some would see this lack of retribution as proof of a merciful God (or that I was not really Jewish because my mother wasn't), but I drew the logical (Occam's razor) conclusion that there was "nothing" there. There are serious problems confronting society and a "humanitarian" God would not have allowed the unaccountable atrocities carried out in the name of any philosophy, religious or otherwise, to happen to anyone let alone to his/her/its chosen people. The desperate need we have for such organisations as Amnesty International has become, for me, one of the pieces of incontrovertible evidence that no divine (mystical) creator (other than the simple Laws of Nature) exists.

The illogical excuses, involving concepts such as free will(!), convoluted into confusing arguments by clerics and other self-appointed guardians of universal morality, have always seemed to me to be just so much fancy (or actually clumsy) footwork devised to explain why the fascinating and beautifully elegant world I live in operates exactly the way one would expect it to in the absence of a mystical power. Of course the excuses have been honed and polished over millenia to retain a hold over those unwilling or unable to accept that, as a Croatian friend of mine once neatly put it, "When you've had it you've had it".

The humanitarian philosophies that have been developed (sometimes under some religious banner and invariably in the face of religious opposition) are human inventions, as the name implies - and our species deserves the credit. I am a devout atheist - nothing else makes any sense to me and I must admit to being bewildered by those, who in the face of what appears so obvious, still believe in a mystical creator. However I can see that the promise of infinite immortality is a more palatable proposition than the absolute certainty of finite mortality which those of us who are subject to free thought (as opposed to free will) have to look forward to and many may not have the strength of character to accept it.

[After all this, I have ended up a supporter of ideologies which advocate the right of the individual to speak, think and write in freedom and safety (surely the bedrock of a civilised society). I have very serious personal problems when confronted by individuals, organisations and regimes which do not accept that these freedoms are fundamental human rights. I feel one must oppose those who claim that the "good" of the community must come before that of the individual - this claim is invariably used to justify oppression by the state. Furthermore there has never been any consensus on what the "good" of the community actually consists of, whereas for individuals there is little difficulty. Thus I am a supporter of Amnesty International, a humanist and an atheist. I believe in a secular, democratic society in which women and men have total equality, and individuals can pursue their lives as they wish, free of constraints - religious or otherwise. I feel that the difficult ethical and social problems which invariably arise must be solved, as best they can, by discussion and am opposed to the crude simplistic application of dogmatic rules invented in past millennia and ascribed to a plethora of mystical creators - or the latest invention; a single creator masquerading under a plethora of pseudonyms. Organisations which seek political influence by co-ordinated effort disturb me and thus I believe religious and related pressure groups which operate in this way are acting antidemocratically and should play no part in politics. I also have problems with those who preach racist and related ideologies which seem almost indistinguishable from nationalism, patriotism and religious conviction.]

My art teacher, Mr Higginson, would give me special tuition at lunch times or after school was over. My father made me finish all my homework and I had to stay up until it was not only complete but passed his inspection - midnight if necessary. As time progressed, for reasons which I am not sure I understand, I gravitated towards chemistry, physics and maths (in that order) and these became my specialist subjects in the 6th form. I was keen on sport, and in school I concentrated on gymnastics whilst outside school I played as much tennis as I could. I patterned my backhand (and my haircut) on that of Dick Savitt and my service on that of Neil Fraser. At one time I remember wanting to be Wimbledon champion but decided that this goal was going to be a bit hard to achieve as I seemed to be having too much difficulty winning.

I started to develop an unhealthy interest in chemistry during enjoyable lessons with Dr. Wilf Jary who fascinated me most with his ability, when using a gas blowpipe to melt lead, to blow continuously without apparently stopping to breath in. I, like almost all chemists I know, was also attracted by the smells and bangs that endowed chemistry with that slight but charismatic element of danger which is now banned from the classroom. I agree with those of us who feel that the wimpish chemistry training that schools are now forced to adopt is one possible reason that chemistry is no longer attracting as many talented and adventurous youngsters as it once did. If the decline in hands-on science education is not redressed, I doubt that we shall survive the 21st century. I became ever more fascinated by chemistry - particularly organic chemistry - and was encouraged by the sixth form chemistry teacher (Harry Heaney, now Professor at Loughborough) to go to. Sheffield University because he reckoned it had, at the time, the best chemistry department in the UK (and perhaps anywhere) - a friendly interview with the amazing Tommy Stephens (compared with a most forbidding experience at Nottingham) settled it.

I was born during the war so I just escaped military service. As all the normal places at Oxbridge were already assigned for the next two years to reemerging national servicemen, I needed to achieve scholarship level to get to Cambridge. This turned out to be a bit difficult as I had been assigned a college with an examination syllabus orthogonal to the one that I had studied. Ian McKellen, the actor, who was in the same year at school, only seems to have needed to remember his lines from his part as Henry V in the school play!

The first day that I arrived in Sheffield, I walked past a building which had a nameplate saying it was the Department of Architecture and was bemused - did people do that at University? I had somehow missed this possibility because general careers advice was non-existent at that time. With hindsight I am sure that with the advice available today I would have done something like architecture which would have conflated my art and technology interests. At Sheffield I did as much as I could. Initially I lived with a family in Hillsborough, near to the Sheffield Wednesday football ground and occasionally watched them - very occasionally as I am a Bolton Wanderers supporter. I played as much tennis as I could which helped to get me a room in a hall of residence (Crewe Hall). I played for the university tennis team and we got to the UAU (Universities Athletics Union) final twice - the team would probably have been champions without me - which they were in 1964. I wanted to continue with some form of art, which was really my passion, and became art editor of "Arrows" (the student magazine which we published each term), specialising in designing the magazine's covers and the screenprinted advertising posters. Whilst a research student I won a Sunday Times bookjacket design competition - the first important (national) prize I was to get for a very long time. Later my cover design for the departmental teaching and research brochure "Chemistry at Sussex" was featured in "Modern Publicity" (an international annual of the best in professional graphic design) - I consider this to be one of my best publications.