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Andreas Sigismund Marggraf (German: [ˈmaʀkɡʀaːf]; 3 March 1709 – 7 August 1782) was a German chemist from Berlin, then capital of the Margraviate of Brandenburg, and a pioneer of analytical chemistry. He isolated zinc in 1746 by heating calamine and carbon. [1]
He did not name his discovery, but Andreas Ekeberg did so when he confirmed it in 1797. [1] Mosander showed later that its ore, yttria , contained more elements. [ 99 ] [ 100 ] In 1808, Davy showed that yttria is a metallic oxide, although he could not isolate the metal.
Zinc is an inexpensive and effective part of treatment of diarrhea among children in the developing world. Zinc becomes depleted in the body during diarrhea and replenishing zinc with a 10- to 14-day course of treatment can reduce the duration and severity of diarrheal episodes and may also prevent future episodes for as long as three months. [174]
The other metals discovered before the Scientific Revolution largely fit the pattern, except for high-melting platinum: Bismuth melts at 272 °C (521 °F) [21] Zinc melts at 420 °C (787 °F), [21] but importantly boils at 907 °C (1665 °F), a temperature below the melting point of silver. Consequently, at the temperatures needed to reduce ...
The chemical elements were discovered in identified minerals and with the help of the identified elements the mineral crystal structure could be described. One milestone was the discovery of the geometrical law of crystallization by René Just Haüy , a further development of the work by Nicolas Steno and Jean-Baptiste L. Romé de l'Isle (the ...
An image from John Dalton's A New System of Chemical Philosophy, the first modern explanation of atomic theory.. This timeline of chemistry lists important works, discoveries, ideas, inventions, and experiments that significantly changed humanity's understanding of the modern science known as chemistry, defined as the scientific study of the composition of matter and of its interactions.
Its identification was based upon the bright-blue lines in its spectrum, and it was the first element discovered by spectrum analysis. Barium (Ba) 56 βαρύς (barys) Greek via Neo-Latin "heavy" βαρύς (barys) means "heavy". The oxide was initially called "barote", then "baryta", which was modified to "barium" to describe the metal.
Zinc and cadmium are electropositive while mercury is not. [23] As a result, zinc and cadmium metal are good reducing agents. The elements of group 12 have an oxidation state of +2 in which the ions have the rather stable d 10 electronic configuration, with a full sub-shell.