ELEMENTLE

Element 104 · Transition Metal

Rutherfordium

Period 7 · Group 4

Rutherfordium is a chemical element with symbol Rf and atomic number 104, named in honor of physicist Ernest Rutherford. It is a synthetic element (an element that can be created in a laboratory but is not found in nature) and radioactive; the most stable known isotope, 267Rf, has a half-life of approximately 1.3 hours. In the periodic table of the elements, it is a d - block element and the second of the fourth - row transition elements.

Three reasons Rutherfordium stands out

  1. 1

    Named after New Zealand physicist who was part of describing the atomic structure.

  2. 2

    It was the first transactinide element to be synthesised, during a fierce Cold War scientific rivalry in the 1960s.

  3. 3

    Its most stable isotope has a half-life of only about 1.3 hours.

The first element beyond the actinides

Rutherfordium opened the transactinide region, where atoms are created one at a time and vanish quickly. American and Soviet teams disputed priority and naming during the Cold War. Fast chemistry later showed that rutherfordium broadly resembles hafnium, as its position predicts.

Rutherfordium at a glance
Atomic number / protons104
SymbolRf
Family (Elementle)Transition Metal
Classification (PubChem)Transition metal
Period7
Group4
Atomic mass (u)267.122
Standard stateBulk state not experimentally established
Electron configuration[Rn]7s2 5f14 6d2
Reported oxidation states+4
Electronegativity (Pauling)Not available
Atomic radius (pm)Not available
First ionization energy (eV)Not available
Electron affinity (eV)Not available
Density (g/cm³)Not available
Melting pointNot available
Boiling pointNot available
Discovery (PubChem)1964

Values are reference data, not a specification for every temperature, pressure, or allotrope. Unknown properties are left unavailable. Superheavy-element predictions remain uncertain.

Sources & further reading

PubChem: Rutherfordium · Rutherfordium on Wikipedia

The introduction and original editorial story are adapted from Wikipedia contributors via Periodic-Table-JSON. Element descriptions and their adaptations are available under CC BY-SA 3.0. Numerical attributes use the PubChem periodic-table dataset, retrieved September 22, 2026.