Friday, October 12, 2007


Nitroglycerin (NG), also known as nitroglycerine, trinitroglycerin, and glyceryl trinitrate, is a chemical compound. It is a heavy, colorless, oily, explosive liquid obtained by nitrating glycerol. It is used in the manufacture of explosives, specifically dynamite, and as such is employed in the construction and demolition industries, and as a plasticizer in some solid propellants. Nitroglycerin is also used medically as a vasodilator to treat heart conditions; it is a venous dilator that decreases waste production.

Nitroglycerin and any or all of the dilutents used can certainly deflagrate or burn. However, the explosive power of nitroglycerin is derived from detonation: energy from the initial decomposition causes a pressure gradient that detonates the surrounding fuel. This can generate a self-sustained shock-wave that propagates through the fuel-rich medium at or above the speed of sound as a cascade of near-instantaneous pressure-induced decomposition of the fuel into gas. This is quite unlike deflagration, which depends solely upon available fuel, regardless of pressure or shock.

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Friday, February 02, 2007

Calcium History

Calcium (Latin calx, meaning "lime") was known of as early as the first century when the Ancient Romans prepared lime as calcium oxide. It was not actually isolated until 1808 in England when Sir Humphrey Davy electrolyzed a mixture of lime and mercuric oxide. Davy was trying to isolate calcium and when he heard that Berzelius and Pontin prepared calcium amalgam by electrolyzing lime in mercury, he tried it himself. He worked with electrolysis throughout his life and also discovered/isolated magnesium, strontium and barium.

Calcium, combined with phosphate to form hydroxylapatite, is the mineral portion of human and animal bones and teeth. The mineral portion of some corals can also be transformed into hydroxylapatite.

Quicklime (CaO) is used in many chemical refinery processes and is made by heating and carefully adding water to limestone. When CaO is mixed with sand it hardens into a mortar and is turned into plaster by carbon dioxide uptake. Mixed with other compounds, CaO forms an important part of Portland cement.

When water percolates through limestone or other soluble carbonate rocks, it partially dissolves part of the rock and causes cave formation and characteristic stalactites and stalagmites and also forms hard water. Other important calcium compounds are nitrate, sulfide, chloride, carbide, cyanamide, and hypochlorite.

Friday, February 03, 2006

Scandium History

Dmitri Mendeleev used his periodic law, in 1869, to predict the existence and some properties of three unknown elements including one he called ekaboron .

Lars Fredrick Nilson and his team, apparently unaware of that prediction in the spring of 1879, were looking for rare earth metals; using spectrum analysis he found a new element within the minerals euxenite and gadolinite. He named it Scandium, from the Latin Scandia meaning "Scandinavia", and by way of isolating the element he processed 10 kilograms of euxenite with other rare-earth residues, obtaining about 2 grams of very pure scandium oxide (Sc2O3).

Per Teodor Cleve concluded that scandium corresponded well to the hoped-for ekaboron, and notified Mendeleev of this in August.

Fischer, Brunger, and Grienelaus prepared metallic scandium for the first time in 1937, by electrolysis of a eutectic melt of potassium, lithium, and scandium chlorides at 700 to 800° C Tungsten wire in a pool of liquid zinc were the electrodes in a graphite crucible. The first pound of 99% pure scandium metal wasn't produced until 1960.

Wednesday, February 01, 2006

Potassium History

Potassium was discovered in 1807 by Sir Humphrey Davy, who derived it from caustic potash (KOH). Potassium was the first metal that was isolated by electrolysis.

Potassium was not known in Roman times, and its names are not Classical Latin.
The name kalium was taken from the word "alkali", which came from Arabic al qalīy = "the calcined ashes".
The name potassium was made from the word "potash", which is English, and originally meant an alkali extracted in a pot from the ash of burnt wood or tree leaves.

Potassium makes up about 2.40% of the weight of the Earth's crust and is the seventh most abundant element in it. As it is very electropositive, potassium metal is difficult to obtain from its minerals.

Potassium salts such as carnallite, langbeinite, polyhalite, and sylvite are found in ancient lake and sea beds. These minerals form extensive deposits in these environments, making extracting potassium and its salts more economical. The principal source of potassium, potash, is mined in California, Germany, New Mexico, Utah, and in other places around the world. 3000 feet below the surface of Saskatchewan are large deposits of potash which are important sources of this element and its salts, with several large mines in operation since the 1960's. Saskatchewan pioneered the use of freezing of wet sands (the Blairmore formation) in order to drive mine shafts through them. See Potash Corporation of Saskatchewan. The oceans are another source of potassium, but the quantity present in a given volume of seawater is relatively low compared to sodium.

Potassium can be isolated through electrolysis of its hydroxide in a process that has changed little since Davy. Thermal methods also are employed in potassium production, using potassium chloride. Potassium is almost never found unbound in nature. However, in living organisms K+ ions are important in the physiology of excitable cells.

Saturday, January 28, 2006

Argon History

Argon (Greek argos meaning "inactive") was suspected to be present in air by Henry Cavendish in 1785 but was not discovered until 1894 by Lord Rayleigh and Sir William Ramsay.

This gas is isolated through liquid air fractionation since the atmosphere contains only 0.934% volume of argon (1.29% mass). The Martian atmosphere in contrast contains 1.6% of Ar-40 and 5 ppm Ar-36. In 2005, the Huygens probe also discovered the presence of Ar-40 on Titan, the largest moon of Saturn.

Before 1962, argon and the other noble gases were generally considered to be chemically inert and not able to form compounds. However, since then, scientists have been able to force the heavier noble gases to form compounds. In 2000, the first argon compounds were formed by researchers at the University of Helsinki. By shining ultraviolet light onto frozen argon containing a small amount of hydrogen fluoride, they were able to form argon hydrofluoride

Friday, January 27, 2006

Chlorine History

Chlorine (Gr. χλωρος, greenish yellow) was discovered in 1774 by Carl Wilhelm Scheele, who mistakenly thought it contained oxygen. Chlorine was given its name in 1810 by Humphry Davy, who insisted that it was in fact an element.

Chlorine gas was first used as weapon against human beings in WWI on April 22nd, 1915.

In nature chlorine is found only as the chloride ion. Chlorides make up much of the salt dissolved in the Earth's oceans—about 1.9% of the mass of seawater is chloride ions. Even higher concentrations of chloride are dissolved in the Dead Sea and in underground brine deposits.

Most chlorides are soluble in water, so solid chlorides are usually only found in abundance in dry climates, or deep underground. Common chloride minerals include halite (sodium chloride), sylvite (potassium chloride), and carnallite (potassium magnesium chloride hexahydrate).

Industrially, elemental chlorine is usually produced by the electrolysis of sodium chloride dissolved in water.

Sulphur History

Sulphur (Sanskrit, sulvere; Latin sulphur) was known in ancient times, and is referred to in the Biblical Pentateuch (Genesis). The word itself is almost certainly from the Arabic sufra meaning yellow, from the bright color of the naturally-occurring form.

English translations of the Bible commonly refer to sulphur as "brimstone", giving rise to the name of 'Fire and brimstone' sermons, which sinners are reminded of their fate of eternal damnation It is from this part of the Bible that hell is implied to "smell of sulphur", although as mentioned above sulphur in fact is odorless. The "smell of sulfur" usually refers to the odor of hydrogen sulfide, e.g. from rotten eggs. Burning sulphur, as may be anticipated in hell (rumor has it) gives sulphur dioxide, the smell associated with burnt matches.

Homer mentioned "pest-averting sulfur" in the 9th century BC and in 424 BC, the tribe of Boeotia destroyed the walls of a city by burning a mixture of coal, sulphur, and tar under them. Sometime in the 12th century, the Chinese invented gun powder which is a mixture of potassium nitrate (KNO3), carbon, and suphur. Early alchemists gave sulphur its own alchemical symbol which was a triangle at the top of a cross. In the late 1770s, Antoine Lavoisier helped convince the scientific community that sulphur was an element and not a compound. In 1867 sulphur was discovered in underground deposits in Louisiana and Texas. The overlying layer of earth was quicksand, prohibiting ordinary mining operations. Therefore the Frasch process was utilized.

Thursday, January 26, 2006

Phosphorus History

Phosphorus (Greek phosphoros, meaning "light bearer" which was the ancient name for the planet Venus) was discovered by German alchemist Hennig Brand in 1669 through a preparation from urine. Working in Hamburg, Brand attempted to distill salts by evaporating urine, and in the process produced a white material that glowed in the dark and burned brilliantly. Since that time, phosphorescence has been used to describe substances that shine in the dark without burning.

Early matches used white phosphorus in their composition, which was dangerous due to its toxicity. Murders, suicides and accidental poisonings resulted from its use (An apocryphal tale tells of a woman attempting to murder her husband with white phosphorus in his food, which was detected by the stew giving off luminous steam). In addition, exposure to the vapors gave match workers a necrosis of the bones of the jaw, the infamous "phossy-jaw." When red phosphorus was discovered, with its far lower flammability and toxicity, it was adopted as a safer alternative for match manufacture.

Due to its reactivity to air and many other oxygen containing substances, phosphorus is not found free in nature but it is widely distributed in many different minerals. Phosphate rock, which is partially made of apatite (an impure tri-calcium phosphate mineral) is an important commercial source of this element. Large deposits of apatite are in Russia, Morocco, Florida, Idaho, Tennessee, Utah, and elsewhere. There are however concerns over how long these phosphorus deposits will last. USA will deplete their deposits around 2035. China and Morocco have the largest known deposits today, but they too will eventually be depleted. During that depletion there could be a serious problem for the worlds food production since phosphorus is such an essential ingredient in fertilizers.

The white allotrope can be produced using several different methods. In one process, tri-calcium phosphate, which is derived from phosphate rock, is heated in an electric or fuel-fired furnace in the presence of carbon and silica. Elemental phosphorus is then liberated as a vapor and can be collected under phosphoric acid.

Wednesday, January 25, 2006

Silicon History

Silicon (Latin silex, silicis meaning flint) was first identified by Antoine Lavoisier in 1787, and was later mistaken by Humphry Davy, in 1800, for a compound. In 1811 Gay Lussac and Thénard probably prepared impure amorphous silicon through the heating of potassium with silicon tetrafluoride. In 1824 Berzelius prepared amorphous silicon using approximately the same method of Lussac. Berzelius also purified the product by repeatedly washing it.

Because silicon is an important element in semiconductor and high-tech devices, the high-tech region of Silicon Valley, California, is named after this element.

Silicon is a principal component of aerolites which are a class of meteoroids and also of tektites which is a natural form of glass.

Measured by weight, silicon makes up 25.7% of the earth's crust and is the second most abundant element on Earth, after oxygen. Elemental silicon is not found in nature. It occurs most often as oxides and as silicates. Sand, amethyst, agate, quartz, rock crystal, flint, jasper, and opal are some of the forms in which the oxide appears. Granite, asbestos, feldspar, clay, hornblende, and mica are a few of the many silicate minerals.

Tuesday, January 24, 2006

Aluminium History

The ancient Greeks and Romans used salts of this metal as dyeing mordants and as astringents for dressing wounds, and alum is still used as a styptic. Further Joseph Needham suggested finds in 1974 showed the ancient Chinese used aluminium. In 1761 Guyton de Morveau suggested calling the base alum 'alumine'. In 1808, Humphry Davy identified the existence of a metal base of alum, which he named (see Spelling section).

Friedrich Wöhler is generally credited with isolating aluminium (Latin alumen, alum) in 1827 by mixing anhydrous aluminium chloride with potassium. However, the metal had been produced for the first time two years earlier in an impure form by the Danish physicist and chemist Hans Christian Ørsted. Therefore almanacs and chemistry sites often list Øersted as the discoverer of aluminium.[2] Still it would further be P. Berthier who discovered aluminium in bauxite ore and successfully extracted it. The Frenchman Henri Saint-Claire Deville improved Wöhler's method in 1846 and described his improvements in a book in 1859, chief among these being the substitution of sodium for the considerably more expensive potassium.

The American Charles Martin Hall of Oberlin, OH applied for a patent (400655) in 1886 for an electrolytic process to extract aluminium using the same technique that was independently being developed by the Frenchman Paul Héroult in Europe. The invention of the Hall-Héroult process in 1886 made extracting aluminium from minerals cheaper, and is now the principal method in common use throughout the world. Upon approval of his patent in 1889, Hall, with the financial backing of Alfred E. Hunt of Pittsburgh, PA, started the Pittsburgh Reduction Company, renamed to Aluminum Company of America in 1907, later shortened to Alcoa.

The statue known as Eros in Piccadilly Circus London, was made in 1893 and is one of the first statues to be cast in aluminium.Aluminium was selected as the material to be used for the apex of the Washington Monument, at a time when one ounce cost twice the daily wages of a common worker in the project.

Germany became the world leader in aluminium production soon after Adolf Hitler seized power. By 1942, however, new hydroelectric power projects such as the Grand Coulee Dam gave the United States something Nazi Germany could not hope to compete with, namely the capability of producing enough aluminium to manufacture sixty thousand warplanes in four years.