Fajans, Kasimir

Faillebin, Marius, 149 Fadheres, Armand, 142 Fajans, Kasimir, 178, 240 Falk, K. G., 132... 

Fajans, Kasimir (1913) Radioactive Transformations and the Periodic System of The Elements Berichte derDeutschen Chemischen Gesellschaft, 46 422-439. 

It was first identified and named brevium, meaning brief, by Kasimir Fajans and O. H. Gohring in 1913 because of its extremely short half-life. In 1918 Otto Hahn (1879—1968) and Lise Meitner (1878-1968) independently discovered a new radioactive element that decayed from uranium into (actinium). Other researchers named it uranium X2. It was not until 1918 that researchers were able to identify independently more of the elements properties and declare it as the new element 91 that was then named protactinium. This is another case in which several researchers may have discovered the same element. Some references continue to give credit for protactinium s discovery to Frederich Soddy (1877—1956) and John A. Cranston (dates unknown), as well as to Hahn and Meitner. 

Protactinium Pa 1913 (Berlin, Germany) 1918 (Berlin, Germany) Kasimir Fajans (Polish) and Otto Gohring (German) Otto Hahn (German), Lise Meitner (Austrian), and John Cranston and Frederick Soddy (both British) 311... 

German physicists Kasimir Fajans and 0. H. Gohring Scarce and radioactive metal whose properties are little known. 

Pa, protactinium, was first identified in 1913 in the decay products of U-238 as the Pa-234 isotope (6.7 h) by Kasimir Fajans and Otto H. Gohring. In 1916, two groups, Otto Hahn and Lisa Meitner, and Frederick Soddy and John A. Cranston, found Pa-231 (10 years) as a decay product of U-235. This isotope is the parent of Ac-227 in the U-235 decay series, hence it was named protactinium (before actinium). Isolation from U extraction sludges yielded over 100 g in 1960. 

Acknowledgment Prof. Kasimir Fajans is thanked for drawing the attention of the author to some of his early work. 

Kasimir Fajans, 1887-. American physical chemist, bom in Poland. Professor at the University of Michigan. Codiscoverer with Gohring of uranium X (brevium). In 1913 he discovered, simultaneously with Soddy, the law of radioactive displacement of elements in the periodic system as the result of o- and /9-ray emission. 

The explanation of the radioactive isotopes was given independently by Alexander S. Russell, Frederick Soddy, and Kasimir Fajans in 1913 (90). With the aid of Alexander Fleck at Glasgow, who had devoted... 

J. Hurwic, Reception of Kasimir Fajans s quanticule theory of the chemical bond a tragedy of a scientist , J. Chem. Educ., 1987, 64 (2), 122-123. 

Letter Pauling to Reymond Holmen, March 1987, as quoted in R. Holmen Kasimir Fajans Bulletin for the History of Chemistry 6 (1990) 7-15. 

In 1913 German-American physicist Kasimir Fajans (1887-1975) and his colleague, O. H. Gohring, claimed to have found element number 91. They suggested the name brevium for the element. They chose the name because the half life of the isotope they found was very short ( brief ). It was only 1.175 minutes. 

Three research teams, consisting of German physicists Lise Meitner and Otto Hahn, Polish-American physical chemist Kasimir Fajans and German chemist O. H. Ghhring, and English physicists Frederick Soddy and John A. Cranston, independently and almost simultaneously discover protactinium. 

Throughout these developments all the major suggestions made by Paneth were vigorously opposed by Kasimir Fajans, as already mentioned here. Fajans disputed the Paneth—von Hevesy replaceability results and later criticized Paneth s elements scheme, believing that individual isotopes of any particular element should indeed be regarded as distinct simple substances and that they should also be regarded as distinct abstract elements. 

Another leading radiochemist, Kasimir Fajans, objected to the interpretation of these results on the basis of a thermodynamic analysis and put forward the view that isotopes are different, not just physically but also chemically (Fajans, 1914). Various other experiments were then devised and carried out in an attempt to settle the issue, but the debate continued and, indeed, was widened to the question of what constitutes a chemical element. 

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