Plutonium (Pu)

Silvery-gray metal

Plutonium is a dense, radioactive actinide that powers deep-space probes and nuclear arsenals, and with [Rn] 5f⁶ 7s², plutonium-238 (half-life 87.7 years) generates 0.57 W/g and powers Voyager, Cassini, and the Curiosity rover. Pu-239 (half-life 24,110 years) is fissile and was used in the first nuclear weapon.

Key metrics

Density19.8g/cm³

Melting point913K

Boiling point3,505K

Electronegativity1.28Pauling

Discovery

1940discovered

Discovered by: Glenn T. Seaborg
Reactivity profile: Highly radioactive and fissile
Reactivity: High
Bonding: Metallic

Electron configuration

\textcolor{#6b7280}{[Rn]}\; \textcolor{#a855f7}{5_{f}^{6}}\; \textcolor{#ef4444}{7_{s}^{2}}

[Rn] 5f6 7s2

Wave function

\Psi_{\text{Pu}} \approx \frac{1}{\sqrt{94!}} \det \left| \chi_1(\mathbf{r}_1) \dots \chi_{94}(\mathbf{r}_{94}) \right|

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

Crystal structure

Monoclinic

Lattice constantsa 1.00 · b 1.30 · c 0.90

Cell anglesα 90° · β 105° · γ 90°

Coordination number—

Atoms per cell—

Atomic packing factor0.55

Physical properties

Atomic radius: 159 pm
Ionization energy: 585 kJ/mol
Electron affinity: 0 kJ/mol
Crystal structure: Monoclinic

Oxidation states

+3+4+5+6

Acid/base

Basic

Strongly acidicStrongly basic

State at 25 °CSolid

913 K3505 K298 K

Emission spectrum

3 transitions

380450500550600650700780

VioletBlueGreenYellowRed

464.2nmPu I (blue)Blue50%

496.3nmPu I (blue-green)Cyan70%

511.4nmPu I (green)Green100%

Dominant line 511.4 nmRange 464–511 nmTransitions 3