In 1936, Szilárd attempted to create a chain reaction using beryllium and indium but was unsuccessful. Nuclear fission was discovered by Otto Hahn and Fritz Strassmann in December 1938 and explained theoretically in January 1939 by Lise Meitner and her nephew Otto Robert Frisch. In their second publication on nuclear fission in February 1939, Hahn and Strassmann used the term uranspaltung (uranium fission) for the first time and predicted the existence and liberation of additional neutrons during the fission process, opening up the possibility of a nuclear chain reaction.