I. The Magnetic Susceptibility of Europium(III) and Europium(II) Ions and the Photochemical Reduction of Water by Europium(II) Ion. II. The Magnetic Susceptibility of Europium and Samarian Amalgams. III. Observations on the Chemistry of Europium. IV. Age Determination from Carbon-14 Content: Ionization Chamber Techniques. V. The Volume Change Due to Hydrogen Bonding of Methanol in Carbontetrachloride Solution

Citation

Douglas, David Lewis (1951) I. The Magnetic Susceptibility of Europium(III) and Europium(II) Ions and the Photochemical Reduction of Water by Europium(II) Ion. II. The Magnetic Susceptibility of Europium and Samarian Amalgams. III. Observations on the Chemistry of Europium. IV. Age Determination from Carbon-14 Content: Ionization Chamber Techniques. V. The Volume Change Due to Hydrogen Bonding of Methanol in Carbontetrachloride Solution. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/9X7A-Y940. https://resolver.caltech.edu/CaltechTHESIS:08312017-152910390

Abstract

The discovery of the photchemical reduction of water by europium(II) ion is reported. By use of a chemical actinometer for determining light intensities and a Gouy balance for following the change in magnetic susceptibility overall quantum yields were determined to be about 0.2 for solutions 0.5 m. in HCl and 0.15 m. in EuCl₂. A mechanism consistent with the experimental data is

Eu(II)·H₂O + hv = Eu(II)*·H₂O

Eu(II)*·H₂O = Eu(III)_aq + H + OH^-_aq

H + H⁺_aq + Eu(II)_aq = Eu(III)_aq + H₂

The thermal reaction under these conditions was found to be relatively unimportant.

The magnetic susceptibility of europium in its liquid amalgam was observed to be 8.09 ± 0.03 Bohr magnetons and that of samarium in its liquid amalgam to be 2.31 ± 0.05 Bohr magnetons.

In a brief investigation europium(II) perchlorate was observed to be quite soluble in water and the solution stable as regards oxidation of the europium. The preparation of europium(II) carbonate is discussed. The possible reduction of CO₂ by the hydrogen atoms produced in the irradiation of Eu(II) solutions was investigated, negative results being obtained.

Using an ionization chamber in conjunction with a very sensitive quartz fiber electroscope, the small amount of C¹⁴ present in "living" carbon was detected. The problem of background ionization observed in the chambers was investigated in detail. Preliminary experiments to determine the suitability of the instruments for the measurement of the age of archeological specimens were carried out. The age of one specimen was observed to be about 3,500 years.

The densities of dilute solutions of CH₃OH in CC₁₄ are reported. A comparison of the partial molar volumes obtained therefrom with the mono­mer fraction of CH₃OH determined by spectroscopic means leads to the conclusion that the average volume of the monomer is only 2% greater than that of the CH₃OH in the polymers.

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