[1][2][3] Throughout his career he worked to precisely define atomic weights for over 40 elements, and served on committees with the purpose of adopting internationally agreed upon values.

[4][5] Hönigschmid studied organic chemistry at the Charles University in Prague under the guidance of Guido Goldschmiedt[6](the discoverer of the structure of papaverine).

[2][1] During this year he learned Richards' Nobel Prize winning methods for precisely determining atomic weights, which earned Hönigschmid credibility in the field.

At the suggestion of Lise Meitner, he recruited Stefanie Horovitz in 1914 to work from his Vienna lab processing lead from uranium-rich pitchblende and measuring its atomic weight to the thousandth of a gram.

[3] Within two years, Hönigschmid and Horovitz demonstrated the second known case of isotopes by showing that ionium, a recently discovered element, was in fact thorium-230.