Chemistry ETDs

Publication Date



In 1934 Szilard and Chalmers found that a large fraction of the radioactive iodine produced in the thermal neutron irradiation of ethyl iodide could be extracted from the irradiated material. The procedure followed was to add a trace of carrier iodine to the irradiated liquid, extract the iodine with an aqueous solution of a reducing agent and precipitate the iodide as silver iodide. The silver iodide precipitate obtained in this manner contained a large fraction of the iodine activity (25-minute I128), at a high specific activity. Since ethyl iodide is not soluble in water and hence is not extracted in the procedure used by Szilard and Chalmers, the experiment shows that in the neutron capture by I127 to form I128, the i128 species is separated from the parent molecule; that is, the carbon-iodine bond is broken. The experiment is of practical interest because it demonstrates that a radioactive element produced in thermal neutron irradiation can be chemically separated, at high specific activity, from the isotopic irradiated material. The products from a large number of (n,ɣ) reactions have since been successfully separated by this type of process, which is generally referred to as the Szilard-Chalmers process. For example, chemical isolation and concentration of radioactive halogens has been shown to be possible as a result of neutron capture by various other organic halids2,3,4,5,6. Rupture of some or all of the molecule has also been shown to occur in the thermal neutron irradiation of selenites and selenates7,8, triphanyl stibine9,10, arsenic hydride11, chlorates12, perchlorates13, bromates14,15 and permanganates16,17.



Document Type


Degree Name


Level of Degree


Department Name

Department of Chemistry and Chemical Biology

First Committee Member (Chair)

Milton Kahn

Second Committee Member

John Francis Suttle

Third Committee Member

Jesse LeRoy Riebsomer

Fourth Committee Member

Roy Thomas

Fifth Committee Member

Carsten Conover Steffens