Ausenium (atomic symbol Ao) and hesperium (atomic symbol Es) were the names initially assigned to the transuranic elements with atomic numbers 93 and 94, respectively. The discovery of the elements, now discredited, was made by Enrico Fermi and a team of scientists at the University of Rome in 1934.

Following the discovery of nuclear fission in 1938, it was realized that "elements" found by Fermi were actually a mixture of barium, krypton, and other elements. The actual elements were discovered several years later, and assigned the names neptunium and plutonium.^[1] Already in 1934, Ida Noddack had presented alternative explanations for the experimental results of Fermi.^[2]

The element 93, ausenium, was named after a Greek name of Italy, Ausonia.^[3] The element 94, hesperium, was named in Italian Esperio after Hesperia, a poetic name of Italy.^[1]

Fascist authorities wanted one of the elements to be named littorio after the Roman lictores who carried the fasces, a symbol appropriated by Fascism.^[1]

• History of nuclear fission

• Element name etymologies. Retrieved February 23, 2010.
• Nobel Prize Presentation Speech given by Professor H. Pleijel, Chairman of the Nobel Committee for Physics on December 10, 1938
• Enrico Fermi, Artificial radioactivity produced by neutron bombardment, Nobel Lecture, December 12, 1938.