NODDACK, WALTER

(b. Berlin, Germany, 17 August 1893; d. Bamberg, West Germany, 7 December 1960) chemistry.

Noddack attended the secondary school in his native city and then entered the University of Berlin in 1912 to study chemistry, physics, and mathematics. World War I interrupted his studies and he therefore did not receive his doctorate until 1920. His dissertation, completed under the direction of W. Nernst, examined Einstein’ law of photochemical equivalence. Noddack then worked for two years with Nernst at the physical Chemistry Institute of the University of Berlin, and in 1922 he became director of the chemical laboratory of the Physikalisch-Technische Reichsanstalt under Nernst.

In 1927 Noddack became director at the newly founded Phytomistry Laboratory in Berlin, but he subsequently accepted an offer from the University of Freiburg to became chairman of the department of physical chemistry (1935). In 1941 he became director of both the physical chemistry department and the Research Institute for Photochemistry at the University of Strasbourg. Following World War II, Noddack offered his services to the Philosophisch- Theologische Hochschule in Bamberg, where instruction in chemistry was being introduced. From 1956 to 1960 he directed the newly established research institute for geochemistry in Bamberg.

Noddack’s principal achievement was the discovery of element seventy-five of the periodic table, which he called rhenium (after the Rhine). He conducted this research in Berlin with his co-worker, Ida Tacke, whom he married in 1926. (Their joint research continued until his death.) They discovered rhenium by X-ray spectroscopy in columbite that had been systematically enriched (Naturwissenschaften, 13 [1925], 567). O. Berg also assisted in the discovery. Although they succeeded in obtaining two milligrams of rhenium from various ores, it was not until 1926, when they produced the first gram of rhenium, that they were able to examine the chemical properties of the new element.

Simultaneously with this discovery, the Noddacks claimed that they had discovered a second new element, element forty-three of the periodic table, which they named masurium. This element was discussed for years in the literature until E. Segré and C. Perrier discovered that it could be produced only artificially; they named the element technetium.

In the field of geochemistry Noddack studied the abundance of individual elements in the crust of the earth and in the universe. This research was based on the evaluation of 1,600 mineral assays. Noddack believed that every element was present in every mineral, but could not be detected in its existing concentrations with the analytic methods then available. He thought that for each element there was a threshold concentration, beyond which the element could be recognized in all minerals; he named this Allgegenwartskonzentration (“omnipresent concentration”) and calculated it for various elements. Noddack also took considerable interest in theoretical and practical questions concerning the rare earths and their separation.

Noddack’s second major field of research was photochemistry. In 1920 he found, on a photographic plate, that under suitable conditions an absorbed quantum hv of blue or ultraviolet radiation corresponds to a silver atom. He then investigated the photographic quantum sensitivity of X and ∞ radiation. In his studies on photographic sensitizing Noddack gave particular attention to the physical properties of the sensitizing coloring substances, and his treatment of photochemical problems in the human eye led him to a new demonstration of the three visual pigments.

BIBLIOGRAPHY

I. Original Works. Noddack and his wife published approximately 100 papers in various periodicals. Their major work is Das Rhenium (Leipzig, 1933).

II. Secondary Literature. H. Meier and E. Ruda, “Zum Tode von Walter Noddack,” in Zeitschrift für Chemie, 2 (1962), 33; and O. Bayer et al., “Walter Noddack,” in Chemische Berichte, 96 (1963), xxvii.

Ferenc Szabadváry