<P> Curium was chemically identified at the Metallurgical Laboratory (now Argonne National Laboratory) at the University of Chicago . It was the third transuranium element to be discovered even though it is the fourth in the series--the lighter element americium was unknown at the time . </P> <P> The sample was prepared as follows: first plutonium nitrate solution was coated on a platinum foil of about 0.5 cm area, the solution was evaporated and the residue was converted into plutonium (IV) oxide (PuO) by annealing . Following cyclotron irradiation of the oxide, the coating was dissolved with nitric acid and then precipitated as the hydroxide using concentrated aqueous ammonia solution . The residue was dissolved in perchloric acid, and further separation was carried out by ion exchange to yield a certain isotope of curium . The separation of curium and americium was so painstaking that the Berkeley group initially called those elements pandemonium (from Greek for all demons or hell) and delirium (from Latin for madness). </P> <P> The curium - 242 isotope was produced in July--August 1944 by bombarding Pu with α - particles to produce curium with the release of a neutron: </P> <Dl> <Dd> 94 239 P u + 2 4 H e ⟶ 96 242 C m + 0 1 n (\ displaystyle \ mathrm (^ (239 \! \,) _ (\ 94) Pu \ + \ _ (2) ^ (4) He \ \ longrightarrow \ _ (\ 96) ^ (242) Cm \ + \ _ (0) ^ (1) n)) </Dd> </Dl>

Curium-242 was synthesized by bombarding an isotope with alpha particles