Otto Hönigschmid

Otto Hönigschmid ( born March 13, 1878 in Horowitz, Bohemia, † October 14, 1945 in Munich, suicide ) was a Bohemian- German chemist.

Life

After graduation he studied in Prague 1897-1901 Chemistry at the University of Prague, received his doctorate in 1901 with Guido Goldschmiedt a working organic chemistry and was employed by him as an assistant. From 1904 to 1906 he worked for Henri Moissan in Paris, where he among other things, to concerned with the extraction of thorium. After his habilitation on carbides and silicides in 1908 in Prague and abroad, he in 1911 became professor at the German Technical University in Prague in 1918 and at the University of Munich.

1932 Hönigschmid was appointed a member of the Leopoldina.

Scientific achievements

He dealt particularly with the development of new, more accurate methods of determining the atomic mass and led to 47 elements by the exact redetermination of the atomic weights.

Of particular importance was the repeated review of the atomic weight of radium, which was first determined by Marie Curie with 226.45. The exact value was to confirm the uranium decay series of great interest. In 1913 he published the value 225.97; In 1933 he determined the value to 226.05 ( IUPAC value 226.0254 u). The experimental effort was at that time relatively large and required very precise work. The value was determined by him on the mass ratio of radium chloride and radium bromide, both substances had to first be made ​​with the utmost purity.

He also dealt with the determination of the atomic masses of isotopes, such as with the separated by Klaus Clusius and G. Dickel chlorine isotopes Cl -35 and Cl -37 and the potassium isotope K -41.