CARL WILHELM SCHEELE: BIOGRAPHY, CONTRIBUTIONS AND DISCOVERIES - BIOLOGY - 2024

Carl Wilhelm Scheele (1742-1786) was a chemist and pharmacist who stood out for discovering a large number of chemical substances, although it was oxygen, which he called the air of fire, the most important element attributed to him. It also helped to discover, isolate and identify the properties of a long list of chemical elements, among which are chlorine or arsenic acid.

His studies covered areas such as organic chemistry where he used different types of fruits to study their acids. From these experiments he was able to isolate citric acid from lemons or lactic acid from milk.

One of the images that seek to illustrate Scheele. Source: Okänd - 1700-tal, via Wikimedia Commons.

Biography

Early years

Carl Wilhelm Scheele was born on December 9, 1742 in Stralsund. The town was the capital of the former Swedish Pomerania, although today it is part of Germany.

Carl was one of eleven children that Joachim Christian Scheele, a brewer and merchant, had with his wife Margaretha Eleonora.

Pharmacy studies

During the Pomeranian War, Carl was sent to Gothenburg to take the place of one of his brothers as a pharmacy apprentice. There he spent long nights reading books on pharmacy and copying experiments to practice. It did not take long for him to acquire a great knowledge of chemistry.

In 1765 he moved to Malmo, where he had a great friendship with Anders Jahan Retzius, a professor at the University of Lund. There Scheele began his studies on combustion and the Prussian blue pigment.

Last days

Despite spending a lot of time exposed to toxic chemicals to conduct his experiments, Scheele's health was characterized by good. Everything changed suddenly during the autumn time of the year 1785. During this time the scientist fell ill suddenly and his health deteriorated very quickly.

Shortly before he died he had married Sara Margaretha Pohl. She had been the housekeeper in charge of Scheele's house in Koping, Sweden.

Contributions and discoveries

The first time Scheele's name appeared in print was in an article by Retzius. The article dealt with the isolation of tartaric acid, which was based on experiments conducted by Scheele.

The first discoveries he managed to document occurred during his time in Malmo. There he spoke for the first time about nitrous acid.

He only spent two years in Malmo before going to Stockholm, from where he tried to publish several of his studies. Between two or three documents with his ideas were rejected by the Royal Academy of Sciences.

Few chemists have been credited with discovering as many chemicals as Scheele.

Pyrolusite

One of his most relevant works was the publication he made in 1774, where he spoke about the mineral pyrolusite. It was a very important finding because it introduced three elements that were new and are currently known as manganese, barium and chlorine.

Chlorine description

In addition, he was the first person to describe chlorine and the first to differentiate the compounds of barium and calcium. Chlorine, for example, was obtained thanks to the oxidation of magnesium with hydrochloric acid. For its part, barium was an impurity present in the mineral pyrolusite.

Preparation of organic substances

Thanks in part to his pharmaceutical knowledge, Scheele was able to prepare a large number of organic substances. Like methods that improved the way of preparing some medical substances.

As a consequence of his chemical study in some animals, he managed to extract phosphorus from the bones, an advance, since the usual practice was to obtain urine. It also separated what is now known as uric acid from the kidneys and urine.

Discovery of oxygen

In Sweden Scheele made his most important discovery when he discovered oxygen, or as he called it: the air of fire. His fascination with fire and combustion led him to study the air.

This discovery was involved in great controversy. The discovery is also attributed to the British Joseph Priestley, as he first published his studies.

Scheele never dated the notes he made in the laboratory throughout his experiments or studies. Some scientists have claimed that he succeeded in completing his studies of oxygen before finishing his publication on manganese in 1773. Most likely, the discovery of oxygen occurred between 1771 and 1772.

Different factors happened that caused Scheele to take a long time to publish his conclusions about oxygen. He was first delayed because he was working on the manganese post. Then he wrote about the newly discovered arsenic acid, and the topic of oxygen was put off. His move to Koping wasn't much help either.

It was finally in the year 1775 that Scheele began to write the manuscript on oxygen. Once completed, it was sent for publication in early 1776. Unfortunately, it took another year for his ideas to come to light, since the people in charge were very slow.

In this way, the first reference to oxygen was made by Priestley in 1775. Although Scheele was also the first to come to the conclusion that the atmosphere was a mixture of oxygen, nitrogen, carbon dioxide and water vapor. Scheele considered these three elements as: fire air, dirty air and air acid.

Publications

His original publications included a large number of full articles, some excerpts from letters written by Scheele, several magazine editorials, and a book.

Curiosities

There is no portrait of Carl Wilhelm Scheele. In 1789, the Royal Academy of Sciences in Sweden released a coin in honor of the scientist. On the coin is a portrait of a person, but it doesn't exactly refer to Scheele. The representation was based on the testimony of several people who described the chemist.

In addition, there is a statue of Scheele in Stockholm that was made in 1892. The image of the statue was born from the imagination of the artist who was in charge of the work.

Finally, a portrait was found in 1931 that was used to design two postage stamps in Sweden. Some time later it was shown that this image also had no relation to Scheele.

References

1. Leicester, H., & Klickstein, H. (1963). A source book in chemistry 1400-1900. Cambridge (Mass.): Harvard University Press.
2. Lennartson, A. (2017). The chemical works of Carl Wilhelm Scheele.. Switzerland: Springer Nature.
3. Scheele, C. (2009). Chemical treatise on air and fire.: Dodo Press.
4. Scheele, C., & Beddoes, T. (1966). The chemical essays of Charles-William Scheele, 1786. London: Dawsons.
5. Scheele, C., & Boklund, U. (1968). Carl Wilhelm Scheele. Stockholm:. Roos boktr. (distr.).