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Discovery
Gallium was discovered in 1875 by the French chemist Paul Émile Lecoq de Boisbaudran using spectroscopy in a sample of the mineral sphalerite (zinc blende). In doing so, he unwittingly confirmed the predictions of the Russian chemist Dmitri Mendeleev. The latter had helped develop the periodic table a few years earlier. However, he had left some gaps where he suspected the existence of as yet unknown elements. He named one of them eka-aluminum, as it was in a column with aluminum in the periodic table and should be chemically similar to it. The properties predicted by Mendeleev coincided with the values later determined by Boisbaudran. The discoverer christened the new element „Gallia“, after the Latin name of his native France; his own name may also have played a role, as „Lecoq“ means „cock“, or „Gallus“ in Latin.
Paul Émile Lecoq de Boisbaudran, AI representation
Extraction
With the increasing commercial importance of gallium, production was also expanded from the 1970s onwards, mainly as a by-product of aluminum extraction. Historically important producing countries were Germany, Japan, South Korea, Russia, Kazakhstan and Australia. Today, they only play a marginal role. From the 1990s onwards, global capacities were greatly expanded, by an average of 7 % per year, according to data from the German Mineral Resources Agency (DERA). Since the mid-2000s, China has massively ramped up its production volume, with the result that the People's Republic now holds a virtual monopoly on gallium. In view of the increasing supply bottlenecks, some former producing countries want to expand their capacities again.
Historical areas of application
The unusual properties of gallium - such as the large difference between its melting and boiling points - were already apparent when it was discovered in 1875. Despite this, the element had little practical use until the middle of the 20th century. This was also due to the fact that it was only a by-product of the extraction of other raw materials. It is also relatively expensive to produce.
From 1951, German chemists led by Heinrich Johann Welker produced pure gallium arsenide crystals for the first time and discovered their outstanding semiconductor properties. The first industrial applications were found in microwave and high-frequency technology, which was used in radar systems, for example. From the mid-1950s, gallium arsenide solar cells were also developed, which proved their worth a few years later, particularly in space travel.
In 1962, US engineer Nick Holonyak Jr. used gallium arsenide phosphide to produce the first LEDs that generated visible - in this case red - light. He thus laid the foundation for another key field of application for gallium. Since the 1990s, galinstan, an alloy of gallium, indium and tin, has been used as a substitute for mercury in clinical thermometers. The big advantage: unlike mercury, the alloy is non-toxic.