Discovery of Aluminum
People have used alum since ancient times for dyeing, tanning and to stop bleeding. Alum is potassium aluminum sulfate.
In the 1750s German chemist Andreas Marggraf found he could use an alkali solution to precipitate a new substance from alum. Marggraf had previously been the first person to isolate zinc in 1746.
The substance Marggraf obtained from alum was named alumina by French chemist Louis de Morveau in 1760. We now know that alumina is aluminum oxide – chemical formula Al2O3.
De Morveau believed alumina contained a new metallic element, but, like Marggraf, he was unable to extract this metal from its oxide.
In 1807 or 1808, English chemist Humphry Davy decomposed alumina in an electric arc to obtain a metal. The metal was not pure aluminum, but an alloy of aluminum and iron.
Davy called the new metal alumium, then renamed it aluminum.
Aluminum was first isolated in 1825 by Hans Christian Ørsted (Oersted) in Copenhagen, Denmark who reported, “a lump of metal which in color and luster somewhat resembles tin.”
Ørsted produced aluminum by reducing aluminum chloride using a potassium-mercury amalgam. The mercury was removed by heating to leave aluminum.
German chemist Friedrich Wöhler (Woehler) repeated Ørsted’s experiment but found it yielded only potassium metal. Wöhler developed the method further two years later, reacting volatalized aluminum trichloride with potassium to produce small amounts of aluminum. In 1856 Berzelius stated that it was Wöhler who had succeeded in 1827. Wöhler is therefore usually given credit for the discovery.
More recently, Fogh repeated the original experiments and has shown that Ørsted’s method can give satisfactory results.
This has strengthened the priority of Ørsted’s original work and his position as discoverer of aluminum.
For almost three decades, aluminum remained a novelty, expensive to produce and more valuable than gold, until in 1854 Henri Saint-Claire Deville in Paris, France found a way of replacing potassium with much cheaper sodium in the reaction to isolate aluminum. Aluminum then became more popular but, because it was still quite expensive, was used in ornamental rather than practical situations.
Finally, in 1886 American chemist Charles Martin Hall and French chemist Paul Héroult independently invented the Hall-Héroult process, which inexpensively isolates aluminum metal from its oxide electrolytically.
Aluminum is still manufactured using the Hall-Héroult process today.
Discovery of Silver
Silver has been in use since prehistoric times. We do not know who its discoverer was, although the discovery would almost certainly have been of native silver.
Nuggets of native silver metal can be found in minerals and sometimes in rivers; but they are rare. Despite native silver’s rarity, very large pieces of it have been found, such as “pieces of native silver as big as stove lids and cannon balls” found in the early 1900s in Northern Ontario, Canada.
Silver has a special place in the history of the elements because it is one of the first five metals discovered and used by humans. The others were gold, copper, lead and iron.
Silver objects dating from before 4000 BC have been found in Greece and from slightly later in Anatolia (in modern Turkey). Silver artifacts have been found in the Sumerian city of Kish dating from about 3000 BC.
Silver and lead often appear together in nature, for example in the mineral galena which is mainly lead sulfide. Galena actually looks metallic (see image) and would have caught the eyes of people looking for metals.
The silver objects found in Greece, Turkey and Kish were made of silver that was refined from lead-containing ores such as galena. (Humans have been successful chemists for a surprisingly long time.)
First the ore was smelted under reducing conditions to obtain a mixture of silver and lead. The metals then went through cupellation: the metals were heated to about 1000 oC in a strong stream of air. Under these conditions lead reacts with oxygen forming lead oxide, leaving liquid silver metal floating on top.
Our name for the element is derived from the Anglo-Saxon for silver, ‘seolfor,’ which itself comes from ancient Germanic ‘silabar.’
Silver’s chemical symbol, Ag, is an abbreviation of the Latin word for silver, ‘argentum.’ The Latin word originates from argunas, a Sanskrit word meaning shining.
The historical association between silver and money is still found in some languages. The French word for silver is argent, and the same word is used for money. The Romans used the word ‘argentarius’ to mean banker (silver trader).
Discovery of Zinc
Zinc ores have been used to make brass (a mixture of copper and zinc) and other alloys since ancient times.
A zinc alloy comprising 87.5% zinc was discovered in an ancient site in Transylvania.
Zinc smelting began in the 12th century in India by reducing calamine (zinc carbonate, ZnCO3) with wool and other organic materials.
The element name is reported to come from the old German word ‘zinke’ meaning pointed; a reference to the sharp pointed crystals formed after smelting.
Credit for isolating the metal is usually given to Andreas Marggraf in 1746, in Berlin. He heated a mixture of calamine ore and carbon in a closed vessel without copper to produce the metal.
Discovery of Nickel
Nickel is present in metallic meteorites and so has been in use since ancient times.
Artifacts made from metallic meteorites have been found dating from as early as 5000 BC – for example beads in graves in Egypt
Iron is the most abundant element in metallic meteorites, followed by nickel.
It was not until the 1750s that nickel was discovered to be an element.
In the 1600s, a dark red ore, often with a green coating, had been a source of irritation for copper miners in Saxony, Germany. They believed the dark red substance was an ore of copper, but they had been unable to extract any copper from it.
In frustration, they had named it ‘kupfernickel’ which could be translated as ‘goblin’s copper’ because clearly, from the miners’ point of view at any rate, there were goblins or little imps at work, preventing them extracting the copper.
Between 1751 and 1754, the Swedish chemist Axel Cronstedt carried out a number of experiments to determine the true nature of kupfernickel. (We now know that kupfernickel is nickel arsenide, NiAs.)
After finding that its chemical reactions were not what he would have expected from a copper compound, he heated kupfernickel with charcoal to yield a hard, white metal, whose color alone showed it could not be copper. Its properties, including its magnetism, led him to conclude that he had isolated a new metallic element.
Cronstedt named the new element nickel, after the kupfernickel from which he had isolated it.
There is a satisfying symmetry in this discovery. Cronstedt was a pupil of George Brandt, who had discovered cobalt, which sits immediately to the left of nickel in the periodic table.
The names of both elements have their origins in the frustrations of miners caused by metal-arsenic ores: nickel arsenide and cobalt arsenide. Cobalt’s name is derived from the German ‘kobold’ meaning ‘goblin’ – a close relative of the creature from which nickel’s name was derived.
In cobalt’s case, miners mistakenly thought the ore contained silver, and called the ore kobold in frustration at the wicked goblins who they believed were preventing them getting silver from the ore.
In the early twentieth century, Ludwig Mond patented a process using nickel carbonyl to purify nickel. This process is still used today.
Discovery of Cobalt
Since ancient times cobalt compounds have been used to produce blue glass and ceramics.
The element was first isolated by Swedish chemist George Brandt in 1735. He showed it was the presence of the element cobalt that caused the blue color in glass, not bismuth as previously thought.
In about 1741 he wrote, “As there are six kinds of metals, so I have also shown with reliable experiments… that there are also six kinds of half-metals: a new half-metal, namely cobalt regulus in addition to mercury, bismuth, zinc, and the reguluses of antimony and arsenic.”
The word cobalt is derived from the German ‘kobold’, meaning goblin or elf.
Discovery of Iron
Iron has been known since ancient times.
The first iron used by humans is likely to have come from meteorites.
Most objects that fall to earth from space are stony, but a small proportion, such as the one pictured, are ‘iron meteorites’ with iron contents of over 90 percent.
Iron corrodes easily, so iron artifacts from ancient times are much rarer that objects made of silver or gold. This makes it harder to trace the history of iron than the less reactive metals.
Artifacts made from meteorite iron have been found dating from about 5000 BC (and so are about 7000 years old) – for example iron beads in graves in Egypt.
In Mesopotamia (Iraq) there is evidence people were smelting iron around 5000 BC.
Artifacts made of smelted iron have been found dating from about 3000 BC in Egypt and Mesopotamia.
In those times, iron was a ceremonial metal; it was too expensive to be used in everyday life. Assyrian writings tell us that iron was eight times more valuable than gold.
The iron age began about 1300-1200 BC when iron became cheap enough to replace bronze.
Adding carbon to iron to make steel was probably accidental at first – a coming together of molten iron and charcoal from the smelting fire. This probably happened about 1000 BC. Until this happened there were few technological reasons for the bronze age to give way to the iron age; the techniques of improving iron by adding carbon (to make steel) and coldworking were needed before iron would be wholly preferred to bronze.
Iron was used commonly in Roman times. In the first century Pliny the Elder said, “It is by the aid of iron that we construct houses, cleave rocks, and perform so many other useful offices in life.”
The origin of the chemical symbol Fe is from the Latin word ‘ferrum’ meaning iron. The word iron itself comes from ‘iren’ in Anglo-Saxon.
Discovery of Chromium
Chromium was discovered in 1780 by French chemist Nicolas Louis Vauquelin in Paris. He discovered the element in a mineral sample of ‘Siberian red lead’- now known as crocoite (lead chromate).
He boiled the crushed mineral with potassium carbonate to produce lead carbonate and a yellow potassium salt solution of chromic acid.
Vauquelin was convinced by further experiments on the solution that he had found a new metal.
In 1781 he succeeded in isolating the metal. Initially he removed the lead from the mineral sample by precipitation with hydrochloric acid. Vauquelin then obtained the oxide by evaporation and finally isolated chromium by heating the oxide in a charcoal oven.
Vauquelin also identified small amounts of chromium in ruby and emerald stones.
Vauquelin went on to discover Beryllium in 1798.
Chromium was named from the Greek word ‘chroma’, meaning color because it forms a variety of colorful compounds.
Discovery of Titanium
Titanium’s discovery was announced in 1791 by the amateur geologist Reverend William Gregor from Cornwall, England.
Gregor found a black, magnetic sand that looked like gunpowder in a stream in the parish of Mannacan in Cornwall, England. (We now call this sand ilmenite; it is a mixture consisting mainly of the oxides of iron and titanium.)
Gregor analyzed the sand, finding it was largely magnetite (Fe3O4) and the rather impure oxide of a new metal, which he described as ‘reddish brown calx.’
This calx turned yellow when dissolved in sulfuric acid and purple when reduced with iron, tin or zinc. Gregor concluded that he was dealing with a new metal, which he named manaccanite in honor of the parish of Mannacan.
Having discovered a new metal, Gregor returned to his pastoral duties.
Little more happens in our story until 1795, when the well-known German chemist Martin Klaproth experienced the thrill of discovering a new metallic element. Klaproth called the new metal titanium, after the Titans, the sons of the Earth goddess in Greek mythology.
Klaproth discovered titanium in the mineral rutile, from Boinik, Hungary. Just like Gregor’s calx, the rutile was a red color. In 1797 Klaproth read Gregor’s account from 1791 and realized that the red oxide in which he had found titanium and the red oxide in which Gregor had found manaccanite were in fact the same; titanium and maccanite were the same element and Gregor was the element’s true discoverer.
Gregor may have beaten Klaproth to the new metal, but scientists preferred Klaproth’s ‘titanium’ to Gregor’s ‘manaccanite.’
Obtaining a sample of pure titanium proved to be much harder than discovering it.
Many scientists tried, but it took 119 years from its discovery until 99.9% pure titanium was isolated in 1910 by metallurgist Matthew Hunter in Schenectady, New York, who heated titanium (IV) chloride with sodium to red-heat in a pressure cylinder.
In 1936, the Kroll Process (heating titanium (IV) chloride with magnesium) made the commercial production of titanium possible. By 1948 worldwide production had reached just 3 tons a year.
By 1956, however, scientists and engineers had realized titanium’s properties were highly desirable and worldwide production had exploded to 25,000 tons a year.
The 2011 forecast for worldwide production of titanium metal using the Kroll process was 223,000 metric tons.
Discovery of Magnesium
Magnesium and calcium were once thought to be the same substance. In 1755 Scottish chemist Joseph Black showed by experiment that the two were different. Black wrote:
“We have already shewn by experiment, that magnesia alba [magnesium carbonate] is a compound of a peculiar earth and fixed air.”
Magnesium was first isolated by Sir Humphrey Davy in 1808, in London, England. Davy had built a large battery and used it to pass electricity through salts. In doing so, he discovered or isolated for the first time several alkali and alkali earth metals.
In magnesium’s case, Davy’s method was similar to the one he used for barium, calcium and strontium.
Davy made a paste of moist magnesium oxide and red mercury oxide. )
He made a depression in the paste and placed about 3.5 grams of mercury metal there to act as the negative electrode. He used platinum as the positive electrode. Davy did the experiment under naphtha (a liquid hydrocarbon under which he had found he could safely store potassium and sodium).
When electricity was passed through the paste, a magnesium-mercury amalgam formed at the mercury electrode. (In later experiments Davy used moist magnesium sulfate instead of the oxide and obtained the amalgam much faster.)
The mercury was then removed from the amalgam by heating to leave magnesium metal.
In a lecture to the Royal Society in June 1808, Davy described how the magnesium he obtained was not pure because of difficulties in removing the mercury entirely from the magnesium. He was, however, able to observe that in air the metal turned into a white powder, gaining weight as it reacted with oxygen and returned to its oxide form.
Davy thought the logical name for the new metal was ‘magnesium’ but instead called it ‘magnium.’
He thought the name ‘magnium’ was, “objectionable, but magnesium has been already applied to metallic manganese…”
By 1812, Davy had changed his mind, following the “candid criticisms of some philosophical friends,” and the new metal became known as magnesium, while metallic manganese became known as… manganese.
Magnesium’s name is derived from magnesia, which Davy used in his experiment. Magnesia is the district of Thessaly in Greece where magnesia alba [magnesium carbonate] was found.
In France, in 1830, Antoine Bussy published his work showing how pure magnesium metal could be obtained. Bussy had read Friedrich Wöhler’s 1828 publication of how he had produced pure aluminum by reacting aluminum chloride with potassium. By analogy, Bussy thought he could do something similar to produce pure magnesium from magnesium chloride; he was correct.
Under red heat he reacted magnesium chloride with potassium vapor and obtained pure magnesium. He wrote, “The metal is silvery white, very brilliant, very malleable, flattens into flakes under a hammer… dilute acids attack the metal, releasing hydrogen.”
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