ISSN:
0018-019X
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The isotopic ion exchange between various forms of 59Fe labelled synthetic Fe3O4 and FeC12-solution was investigated from 9 to 95°C, by measuring the activity of the solution after various reaction times. The observed exchange rate was compared with the theoretically calculated rate for a diffusion controlled reaction. The mathematics of the heterogeneous isotopic ion exchange is discussed. For short times a deviation from the y|√t relationship was observed and attributed to an initial process, superimposed on the diffusion reaction. This initial process probably consists of a rapid exchange of the solution with the first atomic layers of the solid. This problem will be treated mathematically in a subsequent paper. Diffusion coefficients (D8) can be estimated from the slope of the straight line in the y|√t plot. From the temperature dependence of the D8-values the activation energy was calculated to be about 7 kcal/mole and the self diffusion coefficient (D0) of Fe in Fe3O4 was estimated to be 5 ± 3 · 10-6cm2s-1.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/hlca.19630460428
