Shining In the Fields of Optics and Medicine ── Europium

Introduction

Europium (Eu) is found in most rare-earth minerals, but its separation was difficult, so it wasn’t isolated until the late 1800s.

In 1885, William Crookes analyzed the spectra of rare elements and identified some “anomalous” spectral lines, later found to belong to europium.

In 1892, Paul-Émile Lecoq de Boisbaudran first discovered europium by observing spectral lines in samarium-gadolinium concentrates that did not belong to either element.

However, it is generally credited to French chemist Eugène Demarçay, who in 1896 suspected an unknown element in a newly discovered sample of samarium. He successfully isolated europium in 1901, naming it after “Europe.”

In the early 1960s, europium-doped yttrium vanadate red phosphor was discovered. Before this, the red phosphor in color TVs was weak, requiring the suppression of other colors to maintain color balance.

Europium phosphors produce bright red light, making color adjustment unnecessary and allowing for much brighter screens. Since then, europium has been integral to TV and computer screen production.

Europium (Eu)

Atomic number: 63

Atomic weight: 151.964 u

Atomic structure: The outermost electronic structure of europium is 4f⁷6s²。

Physical/chemical properties: Europium is the most reactive of the rare earth metals. At room temperature, it quickly loses its metallic luster in air and oxidizes into powder. Europium reacts vigorously with cold water, releasing hydrogen, and can also react with boron, carbon, sulfur, phosphorus, hydrogen, and nitrogen. It is widely used in making reactor control materials and neutron-shielding materials.

Main Application Areas of Europium

Compared to most elements, europium has limited yet specialized commercial uses, mainly utilizing its phosphorescence in ⁺² or ⁺³ oxidation states.

• Lighting and Display Technology: Europium is a critical component in phosphor manufacturing, used in devices like LCDs, LEDs, and fluorescent lamps. Its ability to emit red and blue phosphorescence makes it essential in display technologies.
  
• MRI Imaging: Europium compounds are occasionally used as contrast agents in MRI, helping to enhance image contrast.
  
• Security Tagging: Europium’s phosphorescent properties make it useful in security labeling for currency, documents, and products to prevent counterfeiting.
  
• Nuclear Power and Research: Some europium isotopes are employed in nuclear reactions and nuclear energy research.
  
• Ceramics and Glass: Europium compounds can be added to ceramics and glass, improving their properties, particularly their optical characteristics.
  

Europium’s unique optical and magnetic properties make it especially valuable in display technology and lighting, with broad applications in other fields as well.