Europium (Eu)

Silvery white, with a pale yellow tint;[1] but rarely seen without oxide discoloration

Europium is the most reactive lanthanide and creates the red and blue phosphors in every TV screen, and with a half-filled 4f⁷ shell, europium uniquely adopts both Eu²⁺ and Eu³⁺ states. Eu³⁺ produces sharp red emission (613 nm) and Eu²⁺ produces blue (420 nm), forming the basis of modern display phosphors.

Key metrics

Density5.24g/cm³

Melting point1,099K

Boiling point1,802K

Electronegativity1.2Pauling

Discovery

1901discovered

Discovered by: Eugène-Anatole Demarçay
Reactivity profile: Highly reactive with air
Reactivity: High
Bonding: Metallic

Electron configuration

\textcolor{#6b7280}{[Xe]}\; \textcolor{#a855f7}{4_{f}^{7}}\; \textcolor{#ef4444}{6_{s}^{2}}

[Xe] 4f7 6s2

Wave function

\Psi_{\text{Eu}} \approx \frac{1}{\sqrt{63!}} \det \left| \chi_1(\mathbf{r}_1) \dots \chi_{63}(\mathbf{r}_{63}) \right|

Probability density $|\Psi|^2$ across the Eu valence shell.

Crystal structure

Body-Centered Cubic

Lattice constantsa = 1.00

Cell anglesα = β = γ = 90°

Coordination number8

Atoms per cell2

Atomic packing factor0.68

Physical properties

Atomic radius: 199 pm
Ionization energy: 547 kJ/mol
Electron affinity: 50 kJ/mol
Crystal structure: Body-centered cubic (bcc)

Oxidation states

+2+3

Acid/base

Basic

Strongly acidicStrongly basic

State at 25 °CSolid

1099 K1802 K298 K

Emission spectrum

3 transitions

380450500550600650700780

VioletBlueGreenYellowRed

462.7nmEu I (blue)Blue70%

532.2nmEu I (green)Green50%

616.0nmEu I (orange)Orange100%

Dominant line 616.0 nmRange 463–616 nmTransitions 3