Plutonium has several radioactive isotopes with different applications. Plutonium-238 supplies decay heat in ceramic fuel used for spacecraft power systems. This is distinct from sustaining a reactor chain reaction: thermoelectric systems turn that continuing heat into electricity for instruments operating far from convenient sunlight.
FROM ELEMENT TO APPLICATION
AN ELEMENT IN CONTEXT
How does plutonium decay heat become spacecraft electricity?
Plutonium-238 oxide in radioisotope power systems
FOLLOW THIS RELATIONSHIP
Identify the fuel form
The heat source uses plutonium-238 in a ceramic oxide form. The isotope and its material containment have different roles within the engineered space-power assembly.
Explore the model (optional)
PuFORM → INTERACTION → CONSEQUENCE
Follow the explanation in either direction. These are authored steps, not a physical clock.
Optional: check your understanding
USE THE EXPLANATION
Which component of the explanation is missing from “plutonium makes electricity”?
Atomic identity, reference properties and structure models
INTERACTIVE 3D94 visible sites
An electron censusDrag to rotate · scroll or pinch to zoom
[Rn] 5f6 7s2. Grouping electrons by principal shell connects the neutral-atom configuration to periodic-table patterns.
What this representation means
A three-dimensional counting diagram. Dots are count markers, not measured electron positions; spherical placement and spacing are arbitrary. There are no electron trajectories here. Orbitals describe quantum states.
Plutonium was produced at Berkeley in late 1940 and chemically identified in 1941 by a team including Glenn Seaborg, Edwin McMillan, Joseph Kennedy and Arthur Wahl. Its name extended the then-familiar planetary sequence beyond uranium and neptunium to Pluto. Subsequent work made its nuclear importance clear, but discovery itself depended on tracing minute quantities and demonstrating that their chemistry belonged to a new element.
1940
First production
Berkeley experiments produce material that includes the new element.
1941
Chemical identification
The team establishes plutonium as a distinct chemical element.
Plutonium used in technology is manufactured through nuclear reactions, principally in uranium-containing material. Tiny natural traces also exist, but they are not a practical resource. The must be named when discussing an application: plutonium-238 selected for heat is different from other plutonium isotopes with other nuclear characteristics.
Plutonium has unusually complicated materials chemistry, including multiple and several solid forms of the metal. Its behaves differently from the elemental material. Nuclear properties depend on isotope, while chemical form governs handling and material performance; neither the word radioactive nor the word metal captures that full distinction.
Each section links its supporting references. Descriptions and diagrams were authored for this atlas. Source checks completed. Source checks dated 2026-09-06.
CITE THIS PAGE
Family labels and the group-3 layout are teaching conventions. A table position does not establish an unknown bulk property. Electronic configurations refer to neutral atoms; ions and material environments require their own account.
Read each reference property together with its units, conditions and the reference information below.
Not yet recorded: electron affinity, second ionization energy, ground-state term symbol, van der waals radius, thermal conductivity, specific heat capacity, electrical resistivity, crystal structure, lattice parameter a, space group, abundance in seawater, abundance in the universe, annual production, supply-risk listing, hazard classification, biological role, cas registry number, pubchem cid, wikidata item. These families are declared and awaiting an ingestion run against the source each names; they are listed here rather than shown as empty rows.
Physical
Intended reference: CRC Handbook of Chemistry and Physics · CRC Press
Phase at 20 °C
solid
293.15 K, 101.325 kPa
Melting point in K
912.5 K
at standard pressure unless noted
Boiling point in K
3505 K
101.325 kPa
Density in g/cm³
19.84 g/cm³
solids and liquids at 293 K; gases at 273 K and 101.325 kPa
Atomic and electronic
Intended reference: Pauling electronegativity scale · Widely tabulated; original in The Nature of the Chemical Bond
Electronegativity in Pauling
1.28 Pauling
Pauling scale
First ionization energy in kJ/mol
584.7 kJ/mol
gas-phase neutral atom, ground state
Covalent radius in pm
187 pm
single-bond covalent radius
Common oxidation states
+4
states met in ordinary compounds; not exhaustive
Occurrence and identity
Intended reference: CRC Handbook of Chemistry and Physics · CRC Press
Abundance in the crust
Not recorded
upper continental crust, mass fraction
Has stable isotopes
Noderived
Discovery year in CE
1940 CEderived
WHERE IT SITS AMONG ITS NEIGHBORS
Electronegativity across period 7
Pu 1.28 Pauling · Plutonium
Electronegativity across period 7. Exact values.
Ra
0.9
Ac
1.1
Th
1.3
Pa
1.5
U
1.38
Np
1.36
Pu
1.28
Am
1.13
Cm
1.28
Bk
1.3
Cf
1.3
Es
1.3
Fm
1.3
Md
1.3
No
1.3
Lr
1.3
The trend uses the same reference-property values as the periodic table. Elements with no recorded value are left out of the line rather than drawn at zero.
