Claus, Carl Ernst

(b. Dorpat, Russia [now Tartu, Estonian S. S. R.] 23 January 1796; d, Dorpat, 24 Merch 1864)

Chemistry, pharmacy.

Although of German origin, Claus was born and died in Russia and carried out all his work there, so the Russia form of his name (Karl Karlovich Klaus) might be considered more appropriate. Orphaned at an early age, he was forced to earn his own living at fourteen, becoming an apprentice to a pharmacist in St. Petersburg. In 1815 he went back to Dorpat, 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. In 1821 he married. 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. In 1831 he became an assistant in the chemistry department at the University of Dorpat; there he began to study chemistry, in which he soon received his bachelor’s and master’s degrees. 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. In 1852 he moved back to Dorpat 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.

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 (1).

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” (2) 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 (3)Despite his isolation in a frontier university of eastern Russia, Claus achieved a worldwide reputation for his research on the platinum metals.

Clau’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 (4) 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) (5).

BIBLIOGRAPHY

I. Original Works. The works referred to in the text are:

(1) Memoirs of the Imperial University of Kazan (Kazan, 18440, pt. III, 15–200 (in Russian); Journal de Pharmacie et de Chimie,8 (1845), 381–385 (in French); Annalen der Chemie and Pharmacie, 56 (1845), 257 (in German); Philosophical Magazine, 27 (1845), 230 (in English).

(2) Festschrife-zur Jubelfeier des 50 jahrigen Bestehens der Universitar Kasan. Copies of this book, which furnished the foundation for all later work on the platinum metals, later became all but unobtainable. A reprint edition was published by the Chemsiche Fabrik Branschweig, G. M. B. H. in 1926

(3) Commissionare der Kaiserlichen Akademie der Wissenschaften (St. Petersburg, 1883). Only three chapters of Claus’s projected book were found on his death. In 1864 these were sent to the Academy of Sciences, and printing was begun but, for some unknown reason, stopped. In 1883 Butlerov, Claus’s former pupli and successor at Kazan, completed the book. James Lewis Howe used the bibliographical section in the compilation of his Bibliography of the Metals of the Platinum Group. Claus’s monograph is extremely rare; presumably only 300 copies were printed, and the only copy still in existence in 1946 outside the Soviet Union was Howe’s copy in the library of the chemistry department at Washington and Lee University, Lexington, Virginia.

(4) “Ueber die Ammoniummloekile der Metalle,” in Annalen der Chemie and Pharmacie,98 (1856), 317–333. An English translation appears in G. B. Kauffman, Classics in Coordination Chemistry, Part II: Selected Papers (1798–1935) (New York, in press).

(5) A. Werner, “Beiträge zur Konstitution an organischer Verbindungen” in Zeitschrift für anorganische Chemie, 3 (1893), 267–330. An English translation appears in G. B. Kauffman, Classics in Coordination Chemistry, Part 1: The Selected Papers of Alfred Werner (New York, 1968), pp. 9–88.

II. Secondary Literature. The source of most biographical data on Claus is B. N. Menshutkin, in Izvestiya Institute po izucheniyu platiny i drugikh blagorodnykh metallov, 6 (1928), 1–11 Biographical data, with emphasis on the discovery of ruthenium, are found in M. E. Weeks, Journal of Chemical Education 9 (1932), 1017–1034; Discovery of the Elements, 6th, ed. (Easton, Pa., 1956), pp. 440–447; and D. McDonald, in Platinum Metals Review, 8 (1964), 67–69.

George B. Kauffman