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Europium is a chemical element; it has symbol Eu and atomic number 63. It is a silvery-white metal of the lanthanide series that reacts readily with air to form a dark oxide coating. Europium is the most chemically reactive, least dense, and softest of the lanthanides. It is soft enough to be cut with a knife.
Europium compounds fluoresce under UV light at 395 nm and 365 nm. [1] Europium compounds are compounds formed by the lanthanide metal europium (Eu). In these compounds, europium generally exhibits the +3 oxidation state, such as EuCl 3, Eu(NO 3) 3 and Eu(CH 3 COO) 3. Compounds with europium in the +2 oxidation state are also known.
Naturally occurring europium (63 Eu) is composed of two isotopes, 151 Eu and 153 Eu, with 153 Eu being the most abundant (52.2% natural abundance).While 153 Eu is observationally stable (theoretically can undergo alpha decay with half-life over 5.5×10 17 years), 151 Eu was found in 2007 to be unstable and undergo alpha decay. [4]
While Eu is an incompatible element in its trivalent form (Eu 3+) in an oxidizing magma, it is preferentially incorporated into plagioclase in its divalent form (Eu 2+) in a reducing magma, where it substitutes for calcium (Ca 2+). [3] Ce and Eu anomalies characteristic of serpentinite found in ultra-slow spreading ridges and transform faults. [4]
The European Union (EU) is a supranational political and economic union of 27 member states that are located primarily in Europe. [ 9 ] [ 10 ] [ 11 ] The union has a total area of 4,233,255 km 2 (1,634,469 sq mi) and an estimated total population of over 449 million.
Europium(III) acetate is an inorganic salt of europium and acetic acid with the chemical formula of Eu(CH 3 COO) 3. In this compound, europium exhibits the +3 oxidation state . It can exist in the anhydrous form, sesqui hydrate [ a ] [ 1 ] and tetrahydrate. [ 2 ]
Europium metal reacts directly with iodine to form europium(III) iodide: [5] 2 Eu + 3 I 2 → 2 EuI 3. Hydrated europium(III) iodide can be prepared dissolving europium(III) oxide or europium(III) carbonate in hydroiodic acid: [1] [6] Eu 2 O 3 + 6 HI + 6 H 2 O → 2 EuI 3 ·9H 2 O. Europium powder reacts with iodine in THF to form a THF adduct ...
Europium(III) carbonate can be obtained by mixing and heating an aqueous solution of ammonium carbonate and europium(III) chloride. [2] A saturated carbon dioxide ammonium carbonate solution (obtained from the reaction of hydrochloric acid and ammonium carbonate solution) can also precipitate europium carbonate from a europium salt solution. [3]