Better known as Aspirin™ or A.S.A., acetylsalicylic acid was developed by Baeyer in the late 1880's in an effort to ease his own father's migraines at a time when willow bark was a commonly used but noxious remedy for pain. It has since become the world's best-known pain reliever. Acetylsalicylic acid reduces fever and is useful in treating the symptoms of various infections, like the common cold. It reduces inflammation and is used for arthritis, rheumatism and muscular aches. It reduces high blood pressure and decreases blood clotting, and is useful for stroke victims. Recently, angina sufferers were found to avoid the recurrence of attacks with small daily doses. It is one of the cheapest and most useful medicines available. Acetaminophen (tylenol) is a closely related compound.

As part of the nitrogen cycle, ammonia is produced in Nature lthough the bacterial decomposition of urea and dung, and the transformation of atmospheric nitrogen. Its pungent odour was recognized in ancient times. Although first synthesized in 1823 by Dobereiner, it was not until Haber perfected his process in the early 1900's that large-scale production started, for which Haber was awarded the Nobel Prize in 1918. Today, it ranks 6th in terms of industrial production, with about 80% going to produce fertilizers, which spawned the Green Revolution. The rest is mainly used in explosives and plastics of many kinds (polyurethanes, nylons, acrylates). A gas that liquefies easily at -330, ammonia is also used in refrigeration, primarily in the food processing industry but also under artificial ice rinks.

The paramount "aromatic" molecule, benzene is a parent of the very large family of molecules known as arenes that enjoy unusual stability by virtue of their electronic structure. Though discovered in 1826 by Faraday, the structure of benzene was elucidated in 1865 by Kekulé, during a daydream about a snake biting its tail. This constituted an important milestone in Organic chemistry. Benzene is obtained from petroleum and is used as a solvent and raw material, with about 90% being converted to polymers, including polystyrene and nylon. It ranks 16th in terms of industrial production.

Also known as C₆₀ or "buckyball" or the "soccer ball molecule", this newly discovered form of carbon is one of a family of hollow, spheroidal molecules called fullerenes, which are found in soot and have unique properties. They are fully aromatic and can encapsulate other molecules. Besides having stirred up much theoretical interest, scientists foresee many exciting applications ranging from drug delivery to superconductors. The discoverers earned the Nobel Prize in 1996.

First identified in the mid-18th century, carbon dioxide has gained enormous utility. It constitutes the planet's main form of available carbon, entering the biotic world through photosynthesis and returning to the atmosphere and oceans through respiration and combustion. Its chief uses in human life are to add fizz to carbonated beverages, as sodium bicarbonate (baking soda) and in fire extinguishers. In solid form, it is known as dry ice because it does not melt, and this is used extensively in refrigeration. It ranks 18th in industrial production, largely as a by-product of hydrogen production.

This fibrous material is a polymer of glucose that differs from starch only in the way that the glucose units are linked. By weight, it makes up about 50% of dry wood and 90% of cotton, where it plays a largely structural role, but ruminant animals like cows have the stomach enzymes needed to break it down and can use woody plant stalks and straw as food. In every-day life, cellulose finds its way into food additives (as methyl cellulose), explosives (cellulose nitrate), plastic film (cellophane), fibers (viscose, rayon and cellulose acetate) and, of course, papers and paper products of all kinds. It is the main component of tissue and cotton balls.

Pure chlorine is a noxious, yellowish green gas, and is not found in Nature. It was first produced in 1774 by Scheele but was not recognized as an element for another 36 years. Today, it is produced by the electrolysis of common sea salt and ranks 8th in terms of industrial production. Its best known uses are as a bleaching agent for paper and textiles, and as a disinfectant of drinking water and swimming pools. About 80% is used to manufacture many organic and inorganic materials, such as vinyl chloride, the raw material to make PVC, and highly pure titanium for aircraft parts.

Cortisone was suspected to exist as early as 1894 when a physician raised his own son's blood pressure with an extract of adrenal glands, which produce cortisone, but it was finally isolated pure only in 1948 and was immediately used to treat rheumatoid arthritis. This earned the discoverers the Nobel Prize in 1950. As a member of the corticosteroid group of hormones that control fat, protein, calcium and carbohydrate metabolism, it has wide utility, for instance in treating tuberculosis, Addison's disease, severe asthma and many other disease states. It has rightly been called a "wonder drug".

Discovered in 1984, cyclosporin A is a cyclic polypeptide produced by the fungus Tolypocladium inflatum. It is an immuno-suppressive drug that has become the primary weapon against graft rejection in organ and bone marrow transplants. In addition, cyclosporin has a role in the treatment of diseases such as nephrotic syndrome, refractory Crohn's disease, ulcerative colitis, biliary cirrhosis, psoriasis, aplastic anemia, rheumatoid arthritis, myasthenia gravis, and dermatomyositis.

In 1894, a watery extract of the adrenal glands was shown to exert dramatic improvements in the symptoms of Addison's disease. Soon thereafter, the catecholamine-class hormone and neurotransmitter epinephrine was isolated and synthesized. Also known as adrenaline, epinephrine is widely recognized as the flight-or-fight hormone. It is medically useful as a bronchodilator for respiratory difficulties, as a cardiac stimulant and vasodilator during cardiac crises, but especially to treat lethal anaphylactic shock arising as severe allergic reactions.

Although not isolated until the 10th century by a Persian scientist, ethanol has been known for about 6000 years in the form of fermentation liquors of all kinds for its apparent stimulant effect, though it actually exerts a strong neurodepressive effect. It can be produced by fermentation of grains, cane sugar and biowaste, but is industrially produced from ethylene. Used since the Middle Ages in medicine, ethanol has strong antiseptic and soporific effects. It is a good cleaning agent, an industrially important solvent and a precursor to products such as acetic acid and ethyl acetate. More recently, it has been advantageously used in combination with gasoline ('gasohol') as motor fuel, and does not add to atmospheric carbon.

Also known as glycerin, this sweet-tasting substance has long been known as a by-product of soap manufacture but was first isolated pure in 1779 and much of it is now made from propylene. Besides its use in making great soap bubbles, glycerol is a food additive, an emollient and humectant for cosmetic and pharmaceutical creams and toothpaste, a specialized lubricant, a plasticizer, an antifreeze and numerous other things. It is also the starting material for synthetic emulsifiers in foods, for nitroglycerin and for alkyd resins for paints and coatings. Recently, its strong water retention has made it useful as a cryoprotectant, as an athlete's tonic to maintain or restore hydration and for dehydrating foliage.

Although very abundant in the universe, helium is too light to be kept by Earth's atmosphere. This lightest of the noble gases is found in natural gas and in other subterranean deposits, having accumulated from the natural decay of radioactive uranium and other elements. The perfect gas for lighter-than-air baloons and dirigibles, it is also used with oxygen in deep sea diving tanks. Its remarkably low boiling point (just 4°C above absolute zero) make liquid helium valuable in cryogenics. In liquid form, it turns metals into superconductors which gives rise to, for example, magnetic resonance imaging (MRI). Its chemical inertness enable its use in arc welding, in nuclear reactor shields and as a carrier for other materials in chromatography and spectroscopy.

Hydrogen peroxide was first discovered in 1818 by the Frenchman Thenard and its bleaching properties were put to use in the 19th century for bleaching straw hats. Industrial production has since grown to over 2 million tonnes annually, and its main use remains the bleaching of natural fibers, such as cotton and wood pulp. It is also used as a topical antiseptic, as a disinfectant in the food industry, as a reagent in the preparation of other materials such as non-chlorine bleaches.

Dr. Frederick Banting and Charles Best were first to isolate insulin in 1921 and use it to treat diabetic dogs. Human patients were first treated a year later. In 1953, Frederick Sanger determined the complete amino acid sequence of the bovine insulin, the first complete amino acid sequence ever determined. Insulin is an important hormone because it helps to maintain a steady blood glucose level in the body. Diabetes mellitus, the third leading cause of death, affects one in 20 people and results from an inability to produce any or enough insulin. Insulin keeps many diabetes sufferers alive and healthy.

A soft, silvery metal, lithium is one of the most reactive elements and was discovered in 1817 by Arfvedson. It is a powerful reducing agent with great industrial and research utility. Its high reduction potential and low weight make it ideal for use in batteries that don't leak, emit gases or explode, and lithium cells have found many applications. Able to absorb neutrons, it is also used in shielding nuclear reactors. As lithium carbonate, it is used medically to treat many psychiatric conditions such as manic depression, and it has immuno-stimulant and anti-viral properties.

Named after the Greek god of dreams Morpheus, morphine is one of the most powerful analgesics known. It is a product of the opium poppy, which has been used since around 4000 B.C. by the ancient Sumerians. Morphine itself was first isolated in 1803 by the German pharmacist Sertürner. It relieves pain while leaving the patient alert and is thus ideal for severe pain conditions owing to cancer or trauma, and is also used for severe diarrhea and dysentery.

Discovered in 1772 by the renowned Joseph Priestley, nitric oxide is one of the few natural compounds with an odd number of electrons, thereby making it a free-radical. Long viewed as an atmospheric pollutant, its biological roles have only recently been elucidated. Despite its short lifetime in the body, it is implicated in immune responses, it is a "messenger molecule" in the cardiovascular system, a regulator of blood pressure, and it is a neurotransmitter linked to learning, memory and, more recently, to erectile function. It is used medically to treat patients in respiratory distress.

Nitroglycerin is best known for its explosive properties. An unstable, highly shock-sensitive yellow, oily liquid, the Swedish chemist Alfred Nobel found that it is greatly stabilized by mixing with kieselguhr (a clay absorbent), producing the well-known dynamite and making Nobel a rich man. It is also a component of smokeless powder. Its medicinal properties are also well appreciated by patients suffering from angina pectoris, where it acts as a vasodilator. Here, nitroglycerin is thought to act as a source of nitric oxide, the causative agent and another Hall of Fame inductee.

Carrothers, working for DuPont, invented nylon in 1934 after developing neoprene and found it to be a strong, elastic yet light plastic that is resistant to abrasion and chemicals, and low in moisture absorbency. First introduced in 1938, it made a big contribution to the Allied effort in World War II by replacing silk in the making of parachutes, while silk sources were under Japanese control. Since then, nylon has penetrated every facet of consumer life, appearing in such automotive, electrical, sports and leisure products as tires, toothbrushes, kites, backpacks, and, of course, in apparel such as windbreakers and women's hosiery.

Best known as the planet's ultraviolet filter, ozone is actually a pollutant at low altitudes. Too unstable to be isolated in bulk, it is generated industrially by an electric arc in air. It is used as a specialized oxidant in the chemical industry, and as a bleaching agent, for instance in wood pulp. It is emerging as a safer disinfectant in replacement of chlorine for drinking water purification, wastewater treatment, aquaculture and in the food industry. It is also used in odour control and air purification.

Actually a family of related compounds, penicillin was the first naturally-occuring antibiotic discovered and the first to be used therapeutically. Though the Scot Sir Alexander Fleming is credited with the discovery in 1928 of the antibacterial action of an extract from a Penicillium mould, the French medical student Ernest Duchesne first recorded the effect of a mould extract on bacterial growth in 1896. The English scientists Florey, Chain and Heatley perfected the isolation of penicillin and performed a clinical trial on mice in 1939. Penicillin is credited with saving many soldiers' lives during WW II and countless more since, and launched the modern era of antibiotics.

Fawcett and Gibson of Imperial Chemical Industries first produced polyethylene by accident in London in 1933, and the first low-density polyethylene (LDPE) production plant opened in 1939. Ziegler in Germany developed a catalyst for its low-pressure synthesis in 1953, resulting in the higher-density material HDPE. Both have excellent resistance to water, chemicals and electricity, and both are non-toxic and recyclable. They are used in everyhting from food wrap, squeeze bottles, laundry hampers to artificial hips, water pipes and electrical insulation.

An important constituent of many minerals and gemstones and the principal component of ordinary beach sand, silica is the raw material for glass, known since antiquity, and the source of elemental silicon, used in integrated circuitry and electronic devices. Quartz, a silica mineral, has useful piezoelectric properties that keep clocks on time. Silica is commonly used as an abrasive, a dessicant, a filler material, as a food additive to maintain fluidity in powders and crystals, and as a chromatographic medium for the purification of chemical compounds. A highly thermostable, refractory substance, it is found in firebrick and on the Space Shuttle's outer coat of insulating tiles.

Silver nitrate is the only simple silver salt that is water-soluble. The light-sensitivity of silver salts was noticed as early as the 17th century by the Italian Sala. Silver nitrate is the starting material for the preparation of silver halides, the light-sensitive stuff of modern photographic emulsions. It is also useful in making the reflective surface of mirrors, in silver plating and in making indelible ink. Its mild antiseptic properties are used to cauterize wounds, to remove warts, to treat eye and skin diseases and to prevent blindness in newborns.

Known since ancient times as a flavour enhancer, sodium chloride or common table salt has served humanity in many other ways. In reflection of its importance, soldiers were once paid with salt (a salary). Long used in food preservation, through salt curing or pickling in brine, salt is the industrial source for the preparation of pure chlorine and numerous sodium derivatives. Salt is also used as an electrolyte, to produce cold temperatures, to thaw ice, to make intravenous solutions, in dyeing and in the making of soap and glass. As it is transparent to infrared light, it is also used to make prisms, lenses and spectroscopic windows.

Produced since at least the 16th century, sulfuric acid is the world's most important industrial chemical substance. In every-day life, the main use is in automobile batteries, but its major use (about 60%) is in the manufacture of fertilizers, since sulfur, along with nitrogen and phosphorus, is a limiting macronutrient for plants. About 10% is used in petroleum refining and metallurgical processes, while most of the rest goes to produce detergents, dyes, drugs, explosives, paint pigments, paper and numerous industrial materials, such as hydrogen chloride. Because of its wide utility, industrial societies have often been measured by their sulfuric acid output.

Polytetrafluoroethylene (PTFE) is better known under Dupont's tradename, Teflon. Accidentally discovered in 1938 by Plunkett working at Dupont, Teflon possesses exceptional durability and resistance to chemical and microbial degradation, to heat and light, and it is non-toxic. These properties make it an invaluable coating on metals and textiles, as insulation material, in medical and industrial tubing, and as a lubricant film, and is found in innumerable products.

Though water is not usually considered in the public's mind as a chemical substance, the importance of this simple chemical compound to Life and to our modern lives cannot be overstated. Though not actually invented nor discovered in the usual sense, its utility dates from the ancient past and reaches far beyond its life-sustaining properties. Its physical properties gave us the water wheel, ore flotation, fire extinguishers, ice boxes and the steam engine, while its chemical properties gave us a universal solvent of immense utility and an industrial raw material for the preparation of numerous materials.