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Discussions
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![](buttons/explanation01.gif) |
The oxidation process:
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At the beginning the Eu was 3+
(Eu III sulfate octahydrate)
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After heating at 300 °C, the water was
remove from the crystal.
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At the beginning of the experiment we had Eu2(SO4)3
powder without water
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In the oxidation phase the Eu2(SO4)3
powder tend to form again the hydrate sulfate and an oxide was form on
the surface of the electrode and passivate the surface.
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The current was very small in the oxidation
phase => an oxide
cover the surface and no PbSO4
crystals was formed on the surface (in the observation area).
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![](cv/expl_oxy.png) |
![](buttons/explanation02.gif) |
The reduction process:
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The peak in the reduction phase can be the
reduction of the Eu3+ to Eu2+
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Eu (III) has the highest standard redox
potential, whitch makes possible its selective reduction [1]:
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The chemical properties of E(II) are similar
to
those of the alkaline earth ions [2]
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![](cv/expl_red.png) |
![](buttons/explanation03.gif) |
Possible candidate
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The electronic configuration of Eu (63) is
similar to Ba (56)
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[Xe].6s2
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[Xe].4f7.6s2
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![](images/Ba.jpg)
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![](images/Eu.jpg)
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![](images/ba.gif)
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![](images/eu.gif)
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EuSO4 is insoluble in water
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Difficult to obtain
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Expensive
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[1]
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T. Hirato, H. Kajiyama, H. Majima, Y. Awakura, Electrolytic
reduction of Eu (III) to Eu (II) in acidic chloride solutions with
titanium cathode. Metall. Mater. Trans. B 26B (1995) 1175-1181.
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[2]
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T. Donohue, Photochemical separation of europium from
lanthanide mixtures in aqueos solutions. J. Chem. Phys. 67 (11) (1997)
5402-5404.
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