Carl Wilhelm Scheele

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Carl Wilhelm Scheele (illustration from 1887)
House Fährstraße 24 ("Scheelehaus") in Stralsund

Carl Wilhelm Scheele (born December 19, 1742 in Stralsund , Swedish Pomerania ; † May 21, 1786 in Köping , Sweden ) was a German-Swedish pharmacist and chemist . He isolated and studied many chemical compounds and contributed to the discovery of several elements , particularly that of oxygen .

Life

Carl Wilhelm Scheele was born as the son of Stralsund brewer and grain merchant Joachim Christian Scheele, a respected citizen of the city, and his wife Margaretha Eleonora, née. Warnkros, born the seventh of eleven children. The father's business went bad at times, and in 1745 he had to file for bankruptcy. Scheele's birthplace and parental home in Fährstraße was also auctioned. The family then lived with relatives and then changed apartments in Stralsund several times. The father worked as a broker and despite little financial means was able to send Carl Wilhelm to a private school in 1748. Little is known about his youth.

At the time of Scheele's birth Stralsund had belonged to Swedish Pomerania since the Thirty Years War . In 1757 Scheele went to Gothenburg in Sweden . He began an apprenticeship in the “Zum Einhorn” pharmacy. The owner of the pharmacy, Martin Andreas Bauch, who comes from Mecklenburg (Güstrow), recognized his apprentice's thirst for knowledge and involved him in the laboratory work. Scheele went to great lengths to study all the specialist books available to him. In 1765 he received his journeyman's certificate and moved to Malmö to the pharmacy “Zum gefleckten Adler”, whose owner Kjellström also promoted and supported Scheele's research. Here Scheele also wrote his first essays on the knowledge gained in his experiments. These were not taken seriously by the academic greats of the time and were rejected. Here in Malmö he met the professor of chemistry at Lund University , Anders Jahan Retzius . He became his supporter and friend. Retzius urged Scheele to work systematically and to produce accurate reports. Both worked together on laboratory tests.

In 1768 Scheele moved to Stockholm and worked in the “Zum Raben” pharmacy. Retzius had followed him to Stockholm and both continued to do research in their free time.

Because of the limited possibilities for further research, Scheele moved to Uppsala in 1770 . Here he found the best conditions for research with the pharmacist Christian Ludwig Lokk, a Pomeranian compatriot, in the pharmacy "Zum Wappen von Uppland". He had access to the laboratory and every freedom to use it. In Uppsala, Scheele tried to get in touch with the learned scientists at Uppsala University . A coincidence helped him to meet the well-known chemist Torbern Olof Bergman . He obtained chemicals from Lokk's pharmacy. A delivery of saltpeter reacted in an unusual way, which could not be unraveled at the university, but Scheele knew the solution and the two very different specialists then worked together. This also ensured recognition of Scheele's work by other scientists, the first treatises on hydrofluoric acid (hydrofluoric acid; 1771) and on brownstone (1774) appeared in the writings of the Royal Academy of Uppsala. In October 1774 Scheele was proposed for admission to the Academy of Sciences and in February 1775 he was accepted. This was an unusual honor for a non-academic like Scheele.

His studies led to the discovery of oxygen and nitrogen in the period from 1772 to 1773 , but he did not publish the results until 1777 in his only book Chemische Abhandlung von der Luft und dem Feuer , whereby he lost some of the fame to Joseph Priestley , who was independent of discovered oxygen for him in 1774.

Scheeles pharmacy in Köping

In Uppsala, too, he suffered from being only able to conduct research as a laboratory assistant. In 1775, however, he was given the opportunity to work as a provisional in the pharmacy in Köping on Lake Mälaren . When the owner Pohl died in April 1775, he took over the pharmacy. The takeover was not a good star, because another provisional made him dispute the pharmacy. Scheele had built a good reputation for himself in Köping in a very short time and with the advocacy of other well-known scientists, the purchase made with the other provisional was canceled. Scheele was also burdened by the pharmacy's debts and the maintenance payments for the widow and her son. In 1777 he traveled to Stockholm. Here he introduced himself as a member of the Royal Academy of Sciences in the presence of the King and received an annual scholarship. Before attending the Collegium medicum, he also passed his exams as a pharmacist as part of his admission to the academy.

He initially carried out his research in a garden shed in the courtyard of the pharmacy and it was not until 1782 that he was able to acquire a new pharmacy with a house and laboratory in a central location.

Scheele discovered the adsorption of gases on charcoal and the catalytic esterification of organic acids by mineral acids. In addition, he boiled vinegar in closed vessels and found a preservation process that was similar to pasteurization .

He made his first experiments with silver chloride and discovered its sensitivity to light, which depends on the spectral composition. Scheele also found out that blackened silver chloride becomes insoluble by ammonia and found - without being aware of it - a fixing agent that ensures the permanence of the image.

In the autumn of 1785 he fell ill. The widow of the deceased previous owner, Sara Margarethe Pohl, b. Sonneman, took care of him and ran his household. When Scheele saw his death approaching, he married her on May 19, 1786 and made her his universal heir in his will. Carl Wilhelm Scheele died on May 21, 1786.

A plaque commemorates the well-known chemist and pharmacist on the house where he was born at Stralsund Fährstrasse 23.

The lunar crater Scheele , the asteroid (12356) Carlscheele and the mineral Scheelite are named after him. The Scheele Prize is named in his honor . The Mecklenburg-Western Pomerania regional group of the German Pharmaceutical Society bears the name "Scheele Society" in his honor.

Discoveries (chemistry)

elements

  • Barium : In 1774 , Scheele and his Swedish colleague Johan Gottlieb Gahn extracted a new type of “earth”, a previously unknown oxide, from the mineral “Bolognese sun stone” ( barium ), which has long been known due to its high density . Scheele's assumption that it was the oxide of a new element was finally confirmed by Humphry Davy in 1808.
  • Chlorine : Scheele was the first to systematically examine what many alchemists must have already learned beforehand. In 1774 he obtained the gas chlorine by oxidizing hydrochloric acid with manganese dioxide. However, Scheele did not realize that this was another new element. This was reserved for Antoine Laurent de Lavoisier , who listed it as early as 1789 in his “Radical muriatique” element list.
    Scheele monument in Köping.
  • Fluorine : The hydrofluoric acid , discovered by Andreas Sigismund Marggraf as early as 1768 , was examined in detail by Scheele from 1771 onwards and wrote several papers on it, which were published again in 1793 by Sigismund Friedrich Hermbstädt . Mainly because of Scheele's work, the acid was also called "Swedish acid" for a long time. It was obtained from the mineral fluorspar , which Scheele very correctly characterized as a lime compound of hydrofluoric acid. Since it attacked all materials available at the time, the representation of the element fluorine was only possible over 100 years later (1886 by Henri Moissan ).
  • Manganese : The manganese minerals known as brownstone ( manganese dioxide and brownstone ) were thought to be a type of iron ore for centuries. It was only Scheele who, through precise analyzes, was able to prove that these minerals do not contain any iron. His colleague Johan Gottlieb Gahn succeeded in reducing manganese oxide to elemental manganese using coal.
  • Molybdenum : Originally the terms "tearing lead", "water lead", "writing lead" and "pottery lead" also applied to graphite and molybdenum sulfide. Graphite was believed to be a form of lead luster ("plumbago"). In 1778, Scheele succeeded in producing molybdenum (VI) oxide (molybdenum trioxide) from molybdenum luster as well as proving that graphite is pure carbon. Despite Scheele's evidence, the term pencil has been used to this day, even though its lead is made of graphite. Scheele's assumption that the compound he had found was the oxide of a new element was confirmed by Hjelm in 1781 by extracting elemental molybdenum from the oxide.
  • Phosphorus : Elemental phosphorus could already be represented beforehand, but only from raw materials that are difficult to obtain. In 1774, Scheele found a method for producing it from bones. Among other things, he made a contribution to the manufacture of matches .
  • Oxygen and nitrogen : Scheele founded gas analysis in 1771 . He found out that air consists of oxygen (“fire air”, “vitriol air”) and nitrogen (“corrupt air”). He also produced oxygen by heating silver and mercury carbonate, mercury oxide, potassium and magnesium nitrate. He did not publish his results until 1777, so that Joseph Priestley is often considered the discoverer of oxygen.
  • Tungsten : From the mineral Tung Sten (Swedish for "heavy stone", since 1820 Scheelite ), Scheele obtained an oxide that two Spanish chemistry students ( Juan José Elhuyar (1754–1796) and Fausto Elhuyar (1755–1833)) in the laboratory of Swedish chemist Torbern Olof Bergman reduced it to elemental tungsten. Although the German name Wolfram has also established itself in Scandinavia, the element with the character W is therefore called “tungsten” or “tungstène” in English and French.

links

literature

Web links

Commons : Carl Wilhelm Scheele  - Collection of images, videos and audio files
Wikisource: Carl Wilhelm Scheele  - Sources and full texts

Individual evidence

  1. ^ Siegfried Ebel and Hermann J. Roth (editors): Lexikon der Pharmazie , Georg Thieme Verlag, 1987, p. 583, ISBN 3-13-672201-9 .
  2. ↑ Georg Lockemann: Scheele. In: The book of great chemists; ed. by Günther Bugge. 2 volumes. Weinheim: Verlag Chemie, 1984 (6th unaltered reprint of the 1st edition 1929), Volume 1, pp. 274–290.
  3. ^ Wolf-Dieter Müller-Jahncke : Scheele, Carl Wilhelm. In: Werner E. Gerabek , Bernhard D. Haage, Gundolf Keil , Wolfgang Wegner (eds.): Enzyklopädie Medizingeschichte. De Gruyter, Berlin / New York 2005, ISBN 3-11-015714-4 , p. 1291.
  4. ^ Hugo Gutsche: Carl Wilhelm Scheele. In: Baltic Studies, New Series Volume 61 (1975) , pp. 53–61.
personal data
SURNAME Scheele, Carl Wilhelm
ALTERNATIVE NAMES Scheele, Karl Wilhelm
BRIEF DESCRIPTION German-Swedish chemist and pharmacist
DATE OF BIRTH December 19, 1742
PLACE OF BIRTH Stralsund
DATE OF DEATH May 21, 1786
Place of death Köping , Sweden