Jöns Jacob Berzelius

Jöns Jacob Berzelius

The Swedish chemist Jöns Jacob Berzelius (1779-1848) was one of the first European scientists to accept John Dalton's atomic theory and to recognize the need for a new system of chemical symbols. He was a dominant figure in chemical science.

Jöns Jacob Berzelius, the son of a clergyman-school-master, was born on Aug. 20, 1779, at Väversunda, Sweden. He studied for 6 years at the medical school at Uppsala and then studied chemistry at the Stockholm School of Surgery. In 1808 he was elected to the Swedish Academy of Science and was appointed its secretary in 1818. He married Elisabeth Poppius in 1835 and on that occasion was made a baron by the Swedish king, Charles XIV.

Atomic Weights and Chemical Symbols

During the first decade of the 19th century, chemists were becoming aware that chemicals combined in definite proportions. This concept, sometimes known as Proust's law after the French chemist Joseph Louis Proust, showed that no matter under what circumstances separate elements combined, their proportions would always be in whole-number ratios. Berzelius was the first to prove beyond a doubt the validity of Proust's law and having been impressed by Dalton's theory of atoms, he proceeded to determine atomic weights. By 1818 Berzelius had obtained, with a high degree of accuracy, the atomic weights of no fewer than 45 elements.

While engaged in this work, Berzelius came to the conclusion that the system of full names for the elements was a hindrance, and he also rejected Dalton's set of symbols for the elements. As a substitute (and this system became the international code for the elements), Berzelius suggested that the initial of the Latin name or the initial plus the second letter be used to designate the element. Now O could be written for oxygen, H for hydrogen, and CO for carbon monoxide. By adding subscriptive numbers, other compounds could be symbolized, such as CO₂ for carbon dioxide and H₂O for water. Thus a new international language of chemistry came into use.

Electricity and Chemistry

The numerous experiments on the effects of an electrical current on chemical solutions had caught the imagination of the scientific world quite early in the 19th century. The electrical current used was that obtained from one of Volta's "galvanic piles." Berzelius and Wilhelm Hisinger worked with the voltaic pile, and in 1803 they reported that, just as an electrical current could decompose water, it could separate solutions of salts so that the acids formed would go to one pole while the alkalies would be collected at the opposite one. In further experiments, with M. M. Pontin, Berzelius succeeded in producing amalgams of potassium, calcium, and ammonia, by using mercury as the negative electrode.

From these experiments in electrochemistry, Berzelius arrived at his own electrochemical theory, which stated that all compounds can be divided into their positive and negative parts. This so-called dualistic theory held that all compounds are divided into two groups: those that are electropositive and those that are electronegative. In any chemical reaction there is a neutralization of opposite electricities, and depending on the strength of the components, this reaction may vary from a very feeble one to ignition and combustion. The opposite of chemical combination, in Berzelius's view, was electrolysis, in which electric charges are restored and the combined molecular groups are separated.

Organic Chemistry

In 1807, when he was appointed professor of medicine at the Stockholm School of Surgery, Berzelius began his researches in organic chemistry. At this time very little was known about organic chemistry, especially its involvement in life processes. Berzelius realized that he himself knew nothing of physiological chemistry. He thought that there might be some chemical process associated with the functions of the brain but admitted that the understanding of this seemed impossible. He began analyzing animal substances such as blood, bile, milk, membranes, bones, fat, flesh and its fluids, and animal semen. He discovered that blood contains iron and that muscular tissue contains lactic acid, the same acid found in sour milk. Most of his work in this field was inconclusive, as he was the first to realize. He concluded that analyses of animal products needed to await the day of more sophisticated techniques and apparatus, and he gave up his studies.

Discovery of New Elements

At an early point in his career, Berzelius became interested in a rare mineral, Bastnäs tungsten, and undertook an analysis of it. He came to the conclusion that it contained an unknown metal, and he and Hisinger named it cerium after the recently discovered asteroid Ceres.

Some years later Berzelius discovered the element selenium, which was isolated from the sediment in lead tanks used in the manufacture of sulfuric acid. He named his new discovery after the Greek word for the moon. His next discoveries, of the elements vanadium and thorium, were named after the Norse goddess Vanadium and the god Thor.

Other Researches

Berzelius's Textbook of Chemistry went through many editions and was translated into the principal European languages. To this work he added his tables of atomic weights. He devised new methods of analysis and obtained values for combining weights not very different from those found today. He started by using the atomic weight figure of 100 for oxygen and related all of the other elements to it.

Much of Berzelius's work involved studies of minerals. He found that previous systems of classification were unreliable, so he proceeded to devise his own system, based not on description of crystal forms but on chemical composition. In 1836 the Royal Society of London awarded him the Copley Medal for this work.

Of great importance to chemical knowledge in the 19th century were two concepts in theory, both of which are associated with Berzelius: isomerism and catalysis. He remembered that the lactic acid he had discovered in muscle tissue behaved differently toward polarized light than the lactic acid of fermentation. Other examples of such behavior could be found, and Berzelius suggested that compounds of the same chemical composition which possess different chemical properties be called isomers, from the Greek word meaning equal parts. The importance of understanding isomerism was that it demonstrates that there is more involved in chemical structure than the ratios of the elements and atomic weight. The manner in which atoms are distributed in a molecular structure is a determining factor in the chemical properties of a compound.

In 1835 Berzelius advanced the theoretical concept of catalysis, or chemical change in which one agent produces the reaction without itself being changed. Berzelius wrote about this process as it applied to plant chemistry. He believed that in inorganic chemical reactions metals can act as catalytic agents. In summing up catalysis, Berzelius wrote, "Thus it is certain that substances … have the property of exerting an effect… quite different from ordinary chemical affinity, in that they promote the conversion … without necessarily participating in the process with their own component parts…."

As secretary of the Swedish Academy of Science, and also for some years as librarian of the academy, Berzelius began in 1821 to publish the Annual Surveys of Progress in the Sciences. Publication was continued until his death, at which time 27 volumes had been issued. His massive correspondence with scientists has been published, and it is a comprehensive picture of the great chemical world which was unfolding in his day.

Personality and Character

It was perhaps natural that Berzelius, who achieved such great eminence early in the century, should have insisted on dominating the chemical sciences as they progressed. He was cheerful as a youth, but as he grew older and developed more and more health problems, he became conservative, argumentative, and even dictatorial. It has been said that when Berzelius condemned a new idea, it might just as well be forgotten, and that his insistence on the acceptance of his own ideas in part blocked the progress of chemistry. In his last years he was still denouncing some of his colleagues for what he termed their "Swedish laziness." He died on Aug. 7, 1848, and was buried in Stockholm.

Further Reading

The biography of Berzelius by J. Erik Jorpes, Jac. Berzelius: His Life and Work (1960; trans. 1971), is highly recommended. There is a long essay on Berzelius by Aaron J. Ihde, which contains many notes and references, in Eduard Farber, ed., Great Chemists (1961). Volume 4 of J. R. Partington, A History of Chemistry (1964), is also useful. On the subject of chemical nomenclature Maurice Crosland, Historical Studies in the Language of Chemistry (1962), should be consulted.

Additional Sources

Melhado, Evan Marc, Jacob Berzelius, the emergence of his chemical system, Stockholm, Sweden: Almqvist & Wiksell International; Madison, Wis.: University of Wisconsin Press, 1981. □