Periodic Table Lab
104Rf[267]

Atomic number 104 · Transition metal

Rutherfordium Rf

Rutherfordium is the first transactinide element and the first transition metal of period 7. It is named after Ernest Rutherford, who discovered the atomic nucleus. It was also the opening battleground of the 'Transfermium Wars', a decades-long dispute between American and Soviet laboratories over who discovered the elements beyond fermium and what they should be called.

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Key properties

Atomic number104
Atomic weight[267] (No stable isotope; mass number of a representative isotope in brackets)
CategoryTransition metal
Group4
Period7
Blockd
State (25 °C, 1 atm)Solid
Melting point—
Boiling point—
Density—
Electronegativity (Pauling)—
Atomic radius (van der Waals)—
First ionization energy—
Electron affinity—
Oxidation states+4
Discovered1964

Electron configuration

Condensed
[Rn]7s2 5f14 6d2
Full
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f14 6s2 6p6 6d2 7s2
Electrons per shell
2 · 8 · 18 · 32 · 32 · 10 · 2

Orbital diagram

1s2↑↓
2s2↑↓
2p6↑↓↑↓↑↓
3s2↑↓
3p6↑↓↑↓↑↓
3d10↑↓↑↓↑↓↑↓↑↓
4s2↑↓
4p6↑↓↑↓↑↓
4d10↑↓↑↓↑↓↑↓↑↓
4f14↑↓↑↓↑↓↑↓↑↓↑↓↑↓
5s2↑↓
5p6↑↓↑↓↑↓
5d10↑↓↑↓↑↓↑↓↑↓
5f14↑↓↑↓↑↓↑↓↑↓↑↓↑↓
6s2↑↓
6p6↑↓↑↓↑↓
6d2↑↑
7s2↑↓

Position in the table

HHeLiBeBCNOFNeNaMgAlSiPSClArKCaScTiVCrMnFeCoNiCuZnGaGeAsSeBrKrRbSrYZrNbMoTcRuRhPdAgCdInSnSbTeIXeCsBaLaCePrNdPmSmEuGdTbDyHoErTmYbLuHfTaWReOsIrPtAuHgTlPbBiPoAtRnFrRaAcThPaUNpPuAmCmBkCfEsFmMdNoLrRfDbSgBhHsMtDsRgCnNhFlMcLvTsOg57–7189–103

Discovery

In 1964 Georgy Flerov's group at the Joint Institute for Nuclear Research in Dubna, in the Soviet Union, reported making element 104 by bombarding plutonium-242 with neon-22 ions. In 1969 Albert Ghiorso's team at Berkeley said it could not reproduce the Soviet result and announced its own synthesis, firing carbon-12 ions at californium-249 to produce rutherfordium-257 and other isotopes.

Neither side accepted the other's claim, and each used its own name. The Soviets proposed 'kurchatovium' (Ku), after Igor Kurchatov, leader of the Soviet atomic bomb programme; the Americans proposed 'rutherfordium'. In 1992 a joint IUPAC–IUPAP working group concluded that credit should be shared. After a provisional proposal in 1994, IUPAC settled the names of elements 104 to 109 together in 1997, and rutherfordium became official.

Origin of the name

The element honours Ernest Rutherford, the New Zealand-born physicist who discovered the nucleus and showed that radioactive decay transforms one element into another. The symbol is Rf.

Main uses

  • Basic research: Only a few atoms can be made, so it has no use outside science.
  • Superheavy chemistry: Rapid one-atom-at-a-time gas-phase and solution experiments have shown that rutherfordium behaves much like hafnium and zirconium, its lighter partners in group 4. It was among the first tests of whether transactinides fit their expected places in the periodic table.

Isotopes

There are no stable isotopes. The longest-lived known isotope, rutherfordium-267, has a half-life of roughly 48 minutes, remarkably long for a superheavy nucleus. It was observed not by direct synthesis but at the end of decay chains from heavier elements. Chemistry experiments generally use isotopes such as rutherfordium-261, which lasts around a minute.

In everyday life

It does not exist in nature; only a few atoms at a time are made in accelerators and they decay almost immediately, so it has no connection with daily life or health.

Good to know

  • The Soviet name 'kurchatovium' was never officially adopted.
  • Rutherfordium is the first element in which the 6d orbitals begin to fill.
  • Its longest-lived known isotope has a half-life of about 48 minutes.

Same group (4)

TiTitaniumZrZirconiumHfHafnium

Data sources · Properties: PubChem Periodic Table (US NIH/NLM public data) · Atomic weights: CIAAW 2024 abridged standard atomic weights · Names: Wikidata (CC0); Korean names follow the Korean Chemical Society. Retrieved 2026-09-23.