Szilard--Chalmers and thermal annealing processes in d-tris(ethylenediamine)cobalt (III) nitrate
The solid-state Szilard-Chalmers process in D-tris(ethylenediamine) cobalt(III) nitrate, caused by the /sup 59/Co(n,..gamma..)/sup 60/Co reaction, was investigated. Seven radiochemical species were separated and characterized. When irradiation and storage conditions suppressed thermal annealing, cobalt(II), isolated as hexaaquocobalt(II) ion in solution, was the predominant radiochemical form isolated. Retention as D- or L-(Co(en)/sub 3/)/sup 3 +/ ion was determined by precipitation with iodide ion and recrystallization to constant specific activity. Less than 1 percent of the total activity appeared as L-(Co(en)/sub 3/)/sup 3 +/. Two radiochemical species, (Co(en)/sub 2/X/sub 2/)/sup n+/ and (Co(en)/sub 2/(NH/sub 3/)X)/sup m+/, were isolated and separated as (Co(en)/sub 2/(NO/sub 2/)/sub 2/)/sup +/ and (Co(en)/sub 2/(NH/sub 3/)(NO/sub 2/))/sup 2 +/ ions in solution. Two unknown radiochemical forms, which were converted to (Co(H/sub 2/O)/sub 6/)/sup 2 +/ in aqueous solution, were detected. The first order rate constants for the conversion of these two species at 30/sup 0/C in aqueous solution were 1.4 x 10/sup -4/ s/sup -1/ and 2.6 x 10/sup -6/ s/sup -1/. Upon post-irradiation thermal treatment between 40 and 160/sup 0/C, the (Co(en)/sub 3/)/sup 3 +/ activity increased at the expense of Co/sup 2 +/ activity, with little change in the activities of the other products below 120/sup 0/C. At 120/sup 0/C (Co(en)/sub 2/X/sub 2/)/sup n+/ decreased with prolonged heating. Isothermal annealing curves did not follow simple first order kinetics. A comparison of isothermal and isochronal annealing curves indicated three annealing processes with activation energies of 100, 95, and 268 kJ/mol. Implication of the experimental results for several models were examined. The experiments agree best with the random fragmentation model for the recoil and the solid state isotopic exchange model for the annealing.
- Research Organization:
- Ames Lab., Ames, IA (United States); Iowa State Univ., Ames, IA (United States)
- Sponsoring Organization:
- US Energy Research and Development Administration (ERDA)
- DOE Contract Number:
- W-7405-ENG-82
- OSTI ID:
- 7251596
- Report Number(s):
- IS-T-725; TRN: 77-000330
- Resource Relation:
- Other Information: Thesis
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COBALT 59
NEUTRON REACTIONS
COBALT 60
HOT ATOM CHEMISTRY
COBALT COMPLEXES
SZILARD-CHALMERS REACTION
ACTIVATION ENERGY
AMINES
ANNEALING
CHEMICAL REACTION KINETICS
COBALT NITRATES
BARYON REACTIONS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CHEMISTRY
COBALT COMPOUNDS
COBALT ISOTOPES
COMPLEXES
ENERGY
HADRON REACTIONS
HEAT TREATMENTS
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
KINETICS
MINUTES LIVING RADIOISOTOPES
NITRATES
NITROGEN COMPOUNDS
NUCLEAR REACTIONS
NUCLEI
NUCLEON REACTIONS
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
RADIOCHEMISTRY
RADIOISOTOPES
REACTION KINETICS
STABLE ISOTOPES
TRANSITION ELEMENT COMPLEXES
TRANSITION ELEMENT COMPOUNDS
YEARS LIVING RADIOISOTOPES
400701* - Radiochemistry & Nuclear Chemistry- Hot-Atom Chemistry