Equilibrium constant (K) values for the formation of Turnbull's blue and Prussian blue have been determined spectrophotometrically at 25 ± 1°. A procedure was used which involved optical measurements in the presence of a large excess of one of the reagents so that the formation of the complex may be considered to be complete. The values of log K = 5.62 ± .03 and log K = 13.89 ± .03 for the formation of Turnbull's blue and Prussian blue, respectively, have been calculated. The ΔH° values for the reactions, Fe^3+ + Fe(CN)_6^4- = Fe^2+ + Fe(CN)_6^3- and Fe^2+ + Fe(CN)_6^3- = Fe[Fe(CN)_6^-], are used in appropriate combination with K values from the present study to calculate the thermodynamic values (ΔS° = 65.4 e.u., ΔH° = 0.55 kcal/mole, ΔG° = -18.95 kcal/mole, log K = 13.89) for Prussian blue formation (Fe^+3 + Fe(CN)_6^4- = Fe[Fe(CN)_6^-]), and to calculate the thermodynamic values ( ΔS° = -24.8 e.u., ΔG° = -7.68 kcal/mole, log K = 5.62) for Turnbull's blue formation. The replacement of the acetylacetonate ions of the bis(acetyl-acetonato)iron(II) species by cyanide ions has been studied by spectro-photometric titration, stoichiometric titration, and elemental analysis.
| Identifer | oai:union.ndltd.org:BGMYU2/oai:scholarsarchive.byu.edu:etd-9502 |
| Date | 01 August 1965 |
| Creators | Wu, Yulin |
| Publisher | BYU ScholarsArchive |
| Source Sets | Brigham Young University |
| Detected Language | English |
| Type | text |
| Source | Theses and Dissertations |
| Rights | http://lib.byu.edu/about/copyright/ |
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