Europium
Definition and meaning of Europium in chemistry.
![Europium element card: symbol Eu, atomic number 63, atomic mass 151.96, electron configuration [Xe] 4f⁷ 6s², oxidation states +3 +2, Lanthanide, f-block, period 6, solid at room temperature.](/assets/images/terms/europium-chemical-element.webp)
Europium is a chemical element with the symbol Eu and the designated atomic number 63. It is a highly reactive, soft, and silvery metal found on the standard periodic table. Chemists formally recognize it as the most reactive of all the rare-earth lanthanide elements.
In more detail
Located deep in the f-block of the periodic table, europium is a remarkably unique element. It is unique among the lanthanides because it readily exists in two different oxidation states. It easily forms both the +2 and +3 oxidation states under standard room temperature conditions.
The exceptional stability of the +2 state is due entirely to its half-filled f-electron shell. An electron shell is the outside part of an atom where the electrons actively orbit. This half-filled shell significantly influences its chemical behavior and dictates its commercial industrial extraction methods.
Because it closely resembles alkaline earth metals in its +2 state, it mimics their specific behavior. It very often substitutes directly for calcium in certain natural minerals found deep in the earth. Europium is the least dense, softest, and most chemically volatile member of the entire lanthanide series.
Chemists extract it slowly from minerals like bastnasite and monazite using complex chemical separation processes. However, its natural concentration within these heavy ores is consistently very low and quite rare. Europium rapidly oxidizes in air and reacts vigorously with water in a manner resembling reactive calcium.
Key facts
| Field | General Chemistry |
|---|---|
| Symbol | Eu |
| Atomic number | 63 |
| Atomic mass | 151.96 u |
| Category | Lanthanide |
| State at room temperature | Solid |
| Melting point | 822 degrees Celsius |
| Year discovered | 1901 |
The single most prominent characteristic of europium compounds is their intense luminescence under ultraviolet light. They emit brilliant red or blue colors depending on the specific oxidation state and host crystal. Europium is critically crucial in the high-volume manufacturing of modern phosphors for electronic screens today. It reliably acts as the primary source of vivid red colors in modern LED lighting displays.
Frequently asked questions
Why is europium explicitly used in anti-counterfeiting measures for international paper currency?
Europium phosphors are widely used in euro banknotes to confidently prevent illegal forgery and counterfeiting. They predictably emit specific, hard-to-forge red and blue colors when exposed to specialized ultraviolet light. This unique glowing effect allows bank tellers to instantly verify the authenticity of the money.
How must highly reactive europium metal be properly stored in a chemistry laboratory?
Europium reacts exceptionally quickly with ambient oxygen and moisture found in normal breathable air. Because of this high reactivity, europium must be safely stored under an inert argon gas. Alternatively, chemists can protect the pure metal by fully submerging it deeply in mineral oil.
Related terms
Sources & references
See our sources and editorial standards.