Carl Wilhelm Scheele

Carl Wilhelm Scheele (9 December 1742 – 21 May 1786) was a Swedish pharmacist and chemist who made several important discoveries in the field of chemistry, including the identification of oxygen (which he called "fire air"), molybdenum, tungsten, manganese, and chlorine. Despite his significant contributions, many of his discoveries were independently made and published later by other scientists, leading to disputes over priority. Scheele is often referred to as "hard-luck Scheele" because he did not receive full credit for his discoveries during his lifetime.

Early Life

Carl Wilhelm Scheele was born in Stralsund, a town which was then part of Swedish Pomerania (now in Germany), on 9 December 1742. He was the seventh child in his family. Showing an early interest in science, Scheele was largely self-taught in the fields of chemistry and pharmacy. In his teenage years, he worked as an apprentice to a pharmacist, which allowed him to conduct his own experiments and lay the foundation for his future discoveries.

Career and Discoveries

Scheele's career was marked by his work in various pharmacies across Sweden and Germany, where he continued his experiments. His most notable work was done in Uppsala, Sweden, where he conducted research that led to the discovery of several chemical elements and compounds.

Oxygen

Scheele is credited with the discovery of oxygen in 1772, although he did not publish his findings until 1777, after Joseph Priestley had independently discovered the element and published his work. Scheele called the gas "fire air" because it supported combustion. He discovered oxygen by heating potassium nitrate, mercuric oxide, and other substances, but did not fully understand the role of oxygen in combustion and respiration.

Other Discoveries

In addition to oxygen, Scheele discovered chlorine by reacting hydrochloric acid with manganese dioxide, a process that produced a greenish-yellow gas with a strong smell. He also identified molybdenum, tungsten, and manganese, and he was the first to prepare hydrogen cyanide, which he called "prussic acid."

Scheele's work extended beyond elemental discoveries. He also made significant contributions to the understanding of acids, isolating tartaric acid, citric acid, and lactic acid. His experiments with plant photosynthesis and the role of light in plant growth were pioneering for his time.

Legacy

Despite his numerous contributions to chemistry, Scheele's work was often overshadowed by that of his contemporaries. He published many of his findings in a book titled Chemical Observations and Experiments on Air and Fire in 1777, but the delayed publication meant that others, like Priestley and Antoine Lavoisier, received more recognition for discoveries he had made earlier.

Carl Wilhelm Scheele died on 21 May 1786, at the age of 43, likely due to his exposure to toxic chemicals throughout his career. Today, he is remembered as one of the most important figures in the history of chemistry, and his work laid the groundwork for future scientific discoveries.