|
General
States Energies Oxidation & Electrons Appearance & Characteristics Reactions Compounds Radius Conductivity Abundance & Isotopes |
|
Fittingly, europium is used in the euro currency
as a preventative measure against forgery. |
General:
| Name: Europium | Symbol: Eu |
| Type: Rare Earth, Lanthanide series | Atomic weight: 151.96 |
| Density @ 293 K: 5.248 g/cm3 | Atomic volume: 20.8 cm3/mol |
| Discovered: Europium was discovered by Eugène-Antole Demarçay in 1901. He isolated europium oxide from a mineral sample of mainly samarium. The element is named after the continent of Europe. | |
States
| State (s, l, g): solid | |
| Melting point: 1095 K (822 oC) | Boiling point: 1873 K (1600 oC) |
Energies
| Specific heat capacity: 0.18 J g-1 K-1 | Heat of atomization: 178 kJ mol-1 |
| Heat of fusion: 9.210 kJ mol-1 | Heat of vaporization : 175.73 kJ mol-1 |
| 1st ionization energy: 546.7 kJ mol-1 | 2nd ionization energy: 1085 kJ mol-1 |
| 3rd ionization energy: 2405 kJ mol-1 | Electron affinity: kJ mol-1 |
Oxidation & Electrons
| Shells: 2,8,18,25,8,2 | Electron configuration: [Xe] 4f7 6s2 |
| Minimum oxidation number: 0 | Maximum oxidation number: 3 |
| Min. common oxidation no.: 0 | Max. common oxidation no.: 3 |
| Electronegativity (Pauling Scale): 1.12 | Polarizability volume: 27.7 Å3 |
Appearance & Characteristics
| Structure: bcc: body-centered cubic | Color: silvery-white |
| Harmful effects: Europium is considered to be moderately toxic. | Hardness: mohs |
|
Characteristics:
Europium is a soft, ductile, silvery-white metal that instantly oxidizes in air. It is the most reactive of the rare earth metals. and ignites in air at temperatures in excess of 150 oC to 180 oC. In water it reacts in a similar way to calcium, producing europium hydroxide and hydrogen gas. |
|
|
Uses:
Europium oxide (europia) is widely used as a doping agent in phosphors in television sets and computer monitors: valency three europium produces a red radiance and valency two europium produces a blue radiance. When both valencies are combined a white light is produced which is used in compact fluorescent bulbs. Europium is also used in phosphors in anti-forgery marks on Euro bank notes. Europium isotopes are good neutron absorbers and are used in nuclear reactor control rods. |
|
Reactions
| Reaction with air: vigorous, ⇒ Eu2O3 | Reaction with 6 M HCl: mild, ⇒ H2, EuCl3 |
| Reaction with 15 M HNO3: mild, ⇒ Eu(NO3)3 | Reaction with 6 M NaOH: |
Compounds
| Oxide(s): Eu2O3 (Europia) | Chloride(s): EuCl3 |
| Hydride(s): EuH2 |
Radius
| Atomic radius: 185 pm | Ionic radius (1+ ion): pm |
| Ionic radius (2+ ion): 131 pm | Ionic radius (3+ ion): 108.7 pm |
| Ionic radius (2- ion): pm | Ionic radius (1- ion): pm |
Conductivity
| Thermal conductivity: 13.9 W m-1 K-1 | Electrical conductivity: 1.1 x 106 S m-1 |
Abundance & Isotopes
| Abundance earth's crust: 1.8 parts per million by weight, 0.2 parts per million by moles | |
| Abundance solar system: 0.5 part per billion by weight, 4 parts per trillion by moles | |
| Cost, pure: $1350 per g | |
| Cost, bulk: $20,000 per 100g | |
| Source: Europium is not found free in nature but is found in a number of minerals mainly monazite, bastnasite and xenotime. Commercially, the metal is produced by the electrolysis of the molten chloride with sodium chloride. | |
| Isotopes: Europium has 30 isotopes whose half-lives are known, with mass numbers 131 to 162. Of these, two are stable, 151Eu and 153Eu. The most abundant isotope is 153Eu at 52.2%. | |
