Jørgensen, Sophus Mads

(b. Slagelse, Denmark, 4 July 1837; d.. Copenhagen, Denmark, 1 April 1914)

chemistry.

The son of Jens Jørgensen, a tailor, and Caroline Grønning, Jørgensen attended school in Slagelse and later studied at the Sorø Velvillie. In 1857 he entered the University of Copenhagen, from which he received his master’s degree in chemistry (1863) and his docotorate (1869) with the dissertation Overjodider af Alkaloiderne (“Polyiodides of Alkaloids”). At the university he became assistant (1864) to Edward Augustus Scharling and director of the chemical laboratories (1867). In 1867 he was also appointed Laerer at the Technical University In 1871 after an engagement of five years, he married Louise Wellmann and also became Lektor at the university. In 1887 he was appointed professor of chemistry, a position which he held until his retirement in 1908

Except for some early isolated organic and inorganic research, Jørgensen devoted himself exclusively to investigating the coordination compounds of cobalt, chromium, rhodium, and platinum; this work, upon which his fame rests, forms an interconnected and continuous series from 1878 to 1906. Jørgensen created no new structural theory of his own. His interpretations of the luteo (hexaammines), purpureo (halopentammines)roseo (aquopentaammines), praseo trans dihalotetraamminesvioleo, (cis-dihalotetraammines), croceo (trans-dinitrotetraammines), flavo (cis-dinitrotetraammines), and other series of coordination compounds were made in light of his logical extensions and modifications of the famous chain theory proposed by the Swedish chemist Christian Wilhelm Blomstrand.

For fifteen years Jørgensen’s views remained the most acceptable of the numerous theories advanced to explain the properties and reactions of the so-called molecular compounds, which were not explicable under the contemporary valence theory. In 1893 Alfred Werner an unknown twenty six-year-old privatdocent at the Eidgenössiche Polytechnikum in Zurich, challenged the old system with his radically new coordination theory [Zeitschrift für anorganische Chemie, 3 (1893), 267-330]. The ensuing controversy between Jørgensen and Werner constitutes an excellent example of the synergism so often encountered in the history of science. Jørgensen regared Werner’s theory as an ad hoc explanation insufficiently supported by experimental evidence and an unwarranted break in the development of theories of chemical structure. In their scholarly rivalry each chemist did the utmost to prove his views, and in the process a tremendous amount of fine experimental work was performed by both. Although not all of Jørgensen’s criticisms [ibid., 19 (1899), 109–157] were valid, Werner in a number of cases was forced to modify various aspects of his theory.

Werner’s ideas eventually triumphed, yet Jørgensen’s experimental observations were in no way invalidated. On the contrary, his experiments, performed with extreme care, have proved completely reliable in most cases and form the foundation not only of the now obsolete Blomstrand- Jørhensen theory but also of Werner’s coordination theory (a debt acknowledged by Werner). It is perhaps not an exaggeration to state that Werner’s theory might never have been propounded had not Jørgensen’s experimental work provided the observations requiring such explanation. Ironically enough, Jørgensen’s work bore the seeds that undid the Blomstrand-Jørgensen theory, for many of the compounds first prepared by him later proved instrumental in demonstrating the validity of Werner’s views When Werner finally succeeded in 1907 in preparing the long-sought cis- dichlorotetraamminecobalt (III)salts [Berichte der Deutschen Chemischen Gesellschaft, 40 (1907), 4817- 4825], whose existence was a necessary consequence of his theory but not of Blomstrand’s Jørgensen graciously capitulated.

A solitary research worker, Jørgensen was methodical and painstaking. Although he could have delegated much routine work to assistants, he insisted on personally performing all his analyses, a task for which he reserved one day a week. In terms of Wilhelm Ostwald’s twofold classification of scientific genius, classic vis-à-vis romantic [E. Farber, Journal of Chemical Education, 30 (1953), 600-604], Jørgensen would seem to be the classic type—the slow and deep-digging scientist who proceeds with careful deliberation and completes a traditional theory or develops it to new consequences. Considering his passion for perfection, his research output was tremendous; and we are indebted to him for many of the basic experimental facts of coordination chemistry.

BIBLIOGRAPHY

The majority of Jørgensen’s papers appeared in the Journal für praktische Chemie (Leipzig), until the founding of the Zeitschrift für anorganische Chemie (1892), after which they began to appear in the latter journal. For a complete list of Jørgensen’s publications (seventy-six papers and nineteen volumes), see Stig Veibel, Kemien i Danmark, II (Copenhagen, 1953).

The details of Jørgensen’s life and a critical discussion of his work and controversy with Alfred Werner are given in G. B. Kauffman, “Sophus Mads Jørgensen (1837-1914): A Chapter in Coordination Chemistry History,” in Journal of Chemical Education, 36 (1959), 521-527, repr. in A. J. Ihde and W. F. Kieffer, eds., Selected Readings in the History of Chemistry (Easton, pa., 1965), pp. 185-191. For a fuller account see G. B. Kauffman, “Sophus Mads Jørgensen and the Werner-Jørgensen Controversy,” in Chymia, 6 (1960), 180-204.

A little-known obituary and evaluation of Jørgensen’s work by his chief scientific adversary is given in A. Werner, Chemiker-Zeitung, 38 (1914), 557-564. Biographical data in Danish can be found in S. P. L. Sørensen, Fysisk Tidsskrift, 12 (1913-1914), 217 and oversigt over dt K. Danske Videnskabernes Selskabs Forhandlinger, 46-49 (1914); and S. Veibel, Dansk biografisk leksikon, XII (Copenhagen, 1937), 253-256.

George B. Kauffman