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Chemistry LibreTexts

Chemistry of Europium

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  • Europium looks and feels a lot like lead, although it is not as dense. It was discovered in 1896 and isolated in 1901 by Demarcay, working with samples of supposedly "pure" samarium. Named for the continent of Europe, the element ranks thirteenth in abundance among the rare earth metals, but there is more of it than silver and gold combined.

    It is the most reactive of the rare earth metals, behaving with water in a manner similar to calcium.

    Generally refined from monazite sand, the pure metal has few applications, but you would find it less interesting to read this without some of its compounds which are used as activators and red phosphors in color CRT screens for television and computers.

    Europium Anomaly

    All lanthanoids tend to group together in nature because all the lanthanoids are most stable in their +3 oxidation state, and their bonding is nearly exclusively ionic/electrostatic. While the lanthanides have valent 4f electrons, the 4f orbitals are radially constricted and cannot achieve appropriate overlap with ligand orbitals to engage in sigma- or pi-bonding interactions. So they can all easily incorporate into similar minerals. Similarly, Europium is most stable in the +3 oxidation state, but can be easily reduced to the +2 oxidation state. This change in Lewis acidity and causes it to phase separate out into other minerals that the relatively hard +3 Lewis acids do not go into. It is well known as the europium anomaly.