Plutonium Properties (25 Facts You Should Know)

Plutonium is an actinoid series radioactive element which undergoes radioactive disintegration due to having an unstable nucleus. Let us focus on the chemical properties of plutonium.

Plutonium is a silvery-gray-colored chemical element that tarnishes after exposure to air and forms a dull coating as a result of oxidation. It was first produced by a deuteron bombardment of uranium (U-238).

Let us discuss the group, period, melting point, boiling point, allotropes, isotopes, ionization energies, and many more relevant topics on plutonium.

Plutonium Symbol

The chemical symbol of plutonium is Pu. This abbreviation comes from the first two alphabets of the word “plutonium”.

Plutonium Group in Periodic Table

Plutonium belongs to the actinide group and the actinide group elements are written under the periodic table separately.

Plutonium Period in Periodic Table

Plutonium belongs to the 7th period in the periodic table between neptunium and americium.

Plutonium Block in Periodic Table

Plutonium is an f-block element because it has a partially filled f-orbital and the last electron of plutonium enters into the 5f-block.

Plutonium Atomic Number

Plutonium has an atomic number of 94 because it has 94 protons and a much higher number of neutrons (145) in its nucleus.

Plutonium Atomic Weight

Plutonium has an atomic mass of 239.05 amu (atomic mass unit) which is regarded as the mass of one plutonium atom. But due to the radioactive nature of plutonium, this mass is decayed into relatively lower masses.

Plutonium Electronegativity according to Pauling

Plutonium shows an electronegativity value of 1.28 on the Pauling scale. But it shows different electronegativity of 1.22 in Allred Rochow’s electronegativity scale.

Plutonium Atomic Density

Plutonium has an atomic density of 19.85 g/cm3.

Plutonium Melting Point

Plutonium possesses a very high melting point of 912.5 K or 639.40 C.

Plutonium Boiling Point

The boiling point of plutonium is also very high 3505K or 32280 C like its melting point.

Plutonium Van der Waals Radius

There is no data on the Van der Waals radius known for plutonium, but it has an atomic radius of 159 pm.

Plutonium Ionic/Covalent Radius

Plutonium has a covalent radius (half of the distance between two atoms attached through covalent bonds) of 187 pm and the ionic radius of 108 pm for Pu3+ ion (+3 is the most stable ion).

Plutonium Isotopes

Isotopes have the same atomic numbers but they differ in the number of neutrons. They also have the same position in the periodic table. Let us find out the isotopes of plutonium.

IsotopesAbundance (in %)Decay mode
238PutraceSpontaneous fission (SF), α
239PutraceSF, α
240PutraceSF, α
241PusynSF, β
242PusynSF, α
244PutraceSF, α
Different Isotopes of Plutonium

Plutonium Electronic Shell

Electronic shells are defined as the different energy states for placing electrons outside the nucleus. Let us find out the electronic shells of plutonium.

Plutonium has a total of 94 electrons in its seven electron shells. They are arranged in the seven shells in 2,8,18,32,24,8, and 2 fashions.

Plutonium Energy of First Ionization

Plutonium has the first ionization energy of 585 KJ/mol.

Plutonium Energy of Second Ionization

Plutonium has the 2nd ionization energy of 1129 KJ/mol which indicates it requires 1129 KJ/mol energy to remove the 2nd electron from its valence shell.

Plutonium Energy of Third Ionization

Plutonium has the third ionization energy of 2103 KJ/mol.

Plutonium Oxidation States

Plutonium can exist in variable oxidation states which are listed below-

  • +2
  • +3 (most common and most stable oxidation state)
  • +4
  • +5
  • +6
  • +7

Plutonium Electron Configurations

Plutonium has an electron configuration which is [Rn] 5f6 7s2.

Plutonium CAS Number

Plutonium has the CAS registry number (unique numeric identifier which can contain upto10 digits) 7440-07-5.

Plutonium ChemSpider ID

Plutonium has the ChemSpider ID (ChemSpider is a free chemical structure database) 22382.

Plutonium Allotropic Forms

Allotropic forms are the different forms of an element that exist in the same physical state. These allotropes differ in their structure and nature. Let us check the allotropes of Pu.

Plutonium exists in six allotropic forms even at ambient pressure. They differ in density and crystal structure.

PhaseCrystal structureDensity (g/cm3)
Alpha (α)Simple monoclinic19.86
Beta (β)Body-centered monoclinic17.70
Gamma (γ)Face-centered orthorhombic17.14
Delta (δ)Face-centered cubic15.92
Delta prime (δ’)Body-centered tetragonal16.00
Epsilon (ε)Body-centered cubic16.51
Different Allotropes of Plutonium

Plutonium Chemical Classification

Plutonium can be chemically classified as an f-block element which is also known as an actinide element which is also radioactive.

Plutonium State at Room Temperature

Plutonium is a solid compound at room temperature (200 C) in its pure form.

Is Plutonium paramagnetic?

An element can be paramagnetic if it has unpaired electrons in it because these unpaired electrons are attracted by the external magnetic field. Let us explain it in detail.

Plutonium is a paramagnetic substance because it contains 6 unpaired (5f6) electrons which are attracted by the external magnetic field and show paramagnetism.

plutonium properties
Unpaired Electrons of Plutonium


Plutonium is used to produce a large amount of heat. Therefore, it is used as a heat (power) source for sensitive electrical components in satellites. It is also applied in different nuclear reactions.

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