The Eight Elements
In the end of the 18th century, the military and amateur geologist Carl Axel Arrhenius found the heavy, black mineral Gadolinite. Successively, eight new elements were extracted from the mineral until the 20th century.
The elements Yttrium, Ytterbium, Terbium, and Erbium were named after Ytterby – one of the two small villages on Resarö (the other village is Överby). The Holmium was named after Holmia, the Latin name for Stockholm, the Scandium after Scandinavia. Thulium was named after Thule which was the Latin name for Scandinavia. They all belong to the rare-earth elements and have a silver metallic colour.
Though, the Tantalum – named after Tantalus in Greek mythology – is a chemical element with a very hard, ductile, lustrous, blue-grey transition metal.
Yttrium (Y)
Yttrium was discovered by the amateur geologist Lieutenant Carl Axel Arrhenius, who worked at the Vaxholm garrison. He brought the discovery to the attention of the Finnish geologist Johan Gadolin (then in Uppsala) in 1794. Later, the mineral was named gadolinite in memory of Johan Gadolin, but it has also been called ytterbit and ytterite. Gadolin is usually considered to be the one who discovered the element yttrium. In the electronics industry, yttrium is an essential component in the manufacture of monitors, LEDs, energy-saving light bulbs, and fiber optic cables.
Terbium (Tb)
Terbium was discovered in 1843 by the Swedish chemist Carl Gustaf Mosander. When used in optical components, it produces a green light (fluorescence). It is used in laser technology, fluorescent lamps, energy-saving light bulbs, and picture tubes for television sets.
Erbium (Er)
Erbium was discovered in 1843 by the Swedish chemist Carl Gustaf Mosander. Erbium finds little use as a metal because it slowly tarnishes in air and is attacked by water. When alloyed with metals such as vanadium, erbium lowers their hardness and improves their workability. Erbium oxide is occasionally used in infrared absorbing glass, for example safety glasses for welders and metal workers. When erbium is added to glass it gives the glass a pink tinge. It is used to give colour to some sunglasses and imitation gems. Broadband signals, carried by fibre optic cables, are amplified by including erbium in the glass fibre.
Ytterbium (Yb)
Ytterbium was discovered in 1878 by the Swiss Jean Charles Galissard de Marignac at the University of Geneva. The story began with yttrium, discovered in 1794, which was contaminated with other rare-earth elements. In 1843, erbium and terbium were extracted from it, and then in 1878, de Marignac separated ytterbium from erbium. He heated erbium nitrate until it decomposed and then extracted the residue with water and obtained two oxides: a red one which was erbium oxide, and a white one which he knew must be a new element, and this he named ytterbium. Even this was eventually shown to contain another rare earth, lutetium, in 1907. Ytterbium is beginning to find a variety of uses, such as in memory devices and tuneable lasers. It can also be used as an industrial catalyst and is increasingly being used to replace other catalysts considered to be too toxic and polluting.
Holmium (Ho):
Holmium was discovered at Geneva in 1878 by Marc Delafontaine and Louis Soret, and independently by Per Teodor Cleve at Uppsala, Sweden. Both teams were investigating Yttrium, which was contaminated with traces of other rare-earths and had already yielded Erbium which was later to yield Ytterbium. Cleve looked more closely at what remained after the ytterbium had been removed, and realised it must contain yet other elements because he found that its atomic weight depended on its source. He separated Holmium from Erbium in 1878. Delafontaine and Soret also extracted it from the same source, having seen unexplained lines in the atomic spectrum.
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Just like the other rare earth elements, Holmium has some kind of interesting magnetic property. It has the highest value of those for the magnetic moment. This means that when Holmium is placed in a magnetic field, the atoms align themselves along the field and concentrate it. This brings the magnetic lines of force closer together and amplifies the local intensity of the field. Thanks to this, a magnet can be strengthened by placing a lump of metal made of Holmium at the end of the magnet. This is used effectively, for example, in magnetic resonance imaging. Another area of use for Holmium is in laser surgery. It can also absorb neutrons, so it is used in nuclear reactors to keep a chain reaction under control.
Thulium (Tm)
In 1879, the Swedish chemist Per Teodor Cleve separated from the rare-earth oxide Erbium another two previously unknown components, which he called Holmia and Thulia; these were the oxides of Holmium and Thulium, respectively. A relatively pure sample of thulium metal was first obtained in 1911.
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Thulium is rare and has a high price but is used as the radiation source in portable X-ray devices and in some solid-state lasers.
Scandinum (Sc)
Scandinum: The existence of Scandium was predicted by the Russian chemist Dmitry Mendeleyev (the originator of the periodic table), who called the probable substance Ekabor. In 1840, the German metallurgist C. J. A. Theodor Scheerer identified a new mineral from Norway with new components, which he called Euxenite. In 1879, Lars Fredrik Nilson (professor of chemistry at Uppsala University) succeeded in isolating a new element based on Euxenite and Gadolinite from the Ytterby mine, whose properties corresponded to those predicted by Mendeleyev. The Swedish chemist Per Teodor Cleve had also noted the same substance in his investigations of rare-earth metals. The minerals Euxenite and Gadolinite had so far only been found in Scandinavia and Lars Fredrik Nilson therefore gave the new element the name Scandium. The metal was not purified until 1937.
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Scandium is mainly used for research purposes. It has, however, great potential because it has almost as low a density as aluminium and a much higher melting point. An aluminium-Scandium alloy has been used in Russian MIG fighter planes, high-end bicycle frames and baseball bats. Scandium iodide is added to mercury vapour lamps to produce a highly efficient light source resembling sunlight. These lamps help television cameras to reproduce colour well when filming indoors or at night-time. The radioactive isotope Scandium-46 is used as a tracer in oil refining to monitor the movement of various fractions. It can also be used in underground pipes to detect leaks.
Tantalum (Ta)
Tantalum was discovered in Sweden in 1802 by Anders Ekeberg at Uppsala University. However, the metal was not in a pure form and some scientist worked to isolate it during the 19th century. In 1903, Werner von Bolton managed to produce pure Tantalum.
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The chemical inertness and very high melting point of Tantalum make it valuable for laboratory and industrial equipment such as reaction vessels and vacuum furnaces. Tantalum alloys can be extremely strong and have been used for turbine blades, rocket nozzles and nose caps for supersonic aircraft.
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One of the main uses of tantalum is in the production of electronic components. An oxide layer which forms on the surface of tantalum can act as an insulating (dielectric) layer. It is used in tantalum capacitors for electronic equipment such as computers. It is being investigated for use as a material for high-quality superconducting resonators in quantum processors. Because Tantalum is very resistant to corrosion and can coat other metals with a very thin layer it is attractive for portable electronics such as mobile phones. Tantalum is considered a technology-critical element (TCE) by the European Commission. It has also found uses as electrodes for neon lights, AC/DC rectifiers and in glass for special lenses.