Karl Ernst Claus

Background

Claus was born on January 23, 1796, in what is now Tartu, Estonia, the son of a painter. Orphaned at an early age, he was forced to earn his own living at fourteen, becoming an apprentice to a pharmacist in St. Petersburg.

Education

Although he had not received formal education, at age 21, Claus managed to pass the State exam on the pharmacist at the Military Medical Academy of St. Petersburg, becoming the youngest pharmacist in Russia at that time.

In 1831 he became an assistant in the chemistry department at the University of Dorpat (now University of Tartu); there he began to study chemistry, in which he soon received his bachelor’s and master’s degrees.

Career

In 1815 Claus went back to his native town, where he passed the pharmacy examination at the university. He then returned to St. Petersburg. An interest in the botanical aspects of pharmacy caused him to move in 1817 to Saratov, where he spent ten years as a pharmacist’s assistant and devoted his leisure to studying the flora and fauna of the Volga steppes.

He opened his own pharmacy in Kazan in 1826 and in a few years was regarded as an authority on the botany and ecology of the steppes. He applied for the vacant chair of pharmacy at the University of Kazan but instead was called of the new chair of chemistry there, an event that seems to have turned him from a pharmacist and botanist into a chemist. Under his direction, the chemistry laboratory, which was opened in 1838, soon acquired a national reputation.

On receiving his doctorate in pharmacy in 1839, Claus was made professor extraordinarius, of chemistry. In 1844, the year of his discovery of ruthenium, he was made professor ordinarius.

Beginning in 1840 Claus started work on the insoluble waste residues from the St. Petersburg platinum refineries, previously investigated (1828) by J. J. Berzelius and G. W. Osann, formerly professor of chemistry and physics at the University of Dorpat. In these residues, Berzelius had found only rhodium, palladium, osmium and iridium, but Osann claimed the presence of these new metals-pluranm ruthen, and polin. Claus resolved the issue by two years of intensive work (1842-1844); from two pounds of residue, he was able to extract six grams of the last platinum metal to be discovered. He named it ruthenium from the Latin word for Russia, thus honoring his homeland and Osann.

Claus also carried out extensive research on iridium, rhodium, and osmium, and in 1854 all his papers on this subject were collected and published as “Beiträge zur Chemie der Platinmetalle” in a jubbilee volume in honor of the fiftieth anniversary of the founding the University of Kazan. His monograph on the history, chemistry, and applications of the platinum metals, left unfinished at his death, was eventually published posthumonsly in 1883 as Fragment einer Monographie des Platins and der Platinmetalle. Despite his isolation in a frontier university of eastern Russia, Claus achieved a worldwide reputation for his research on the platinum metals.

Claus’s second best-known contribution to chemistry resulted from his research on platinum ammines. In 1856 he proposed a theory that attempted to explain the formation of such compounds and that recognized the analogy between metal ammines and salt hydrates. He believed that on combination with metallic oxides, ammonia does not affect the saturation capacity of the metal and that it loses its basicity and becomes “passive”. Claus’s theory encountered vigorous opposition, but his views were later vindicated when they appeared in only slightly modified from in Alfred Werner’s coordination theory (1893).

In 1852 he moved back to Tartu to occupy a newly created chair of pharmacy at the university, where he continued his work on the platinum metals. In 1861 he became a corresponding member of the Russian Academy of Sciences, and in 1863 the Russian government sent him to Western Europe to visit laborations and platinum refineries. In 1864, on returning home from a scientific meetings in St. Petersburg, he caught a chill, fell, ill and died.

Achievements

• Claus was primarily known as a chemist and discoverer of the chemical element ruthenium, but also as one of the first scientists who applied quantitative methods in botany.

Membership

• Corresponding member

  Russian Academy of Sciences , Russian Federation

  1861

Personality

Claus was known for his negligent attitude towards his health. In particular, he often tasted his chemicals and new compounds and tested the strength of the acids by dipping a finger in them and touching his tongue with it. Once he severely burned his mouth while tasting one of the new ruthenium compounds that he had synthesized.

Connections

In 1821, Claus married Ernestine Bate whom he knew since his youth. They had three daughters born in Kazan and later a son, when they moved back to Tartu.

Spouse:

Ernestine Bate

References

• Annalen der Physik und Chemie German Edition
  1845
• Dictionary of Scientific Biography Volume 3
  1971