---
title: "Rutherfordium (Rf) — element 104"
description: "Rutherfordium is element 104, symbol Rf, most stable isotope 267. Configuration, properties, uses and neighbours."
url: https://atoneplace.net/element/rutherfordium/
site: "At One Place"
---

# Rutherfordium (Rf)

**Rutherfordium — element 104: Rf**

[267] · Transition metal · period 7, group 4

Rutherfordium was the first element past the actinides, and confirming that it behaves like a group 4 metal — forming a volatile chloride the way zirconium and hafnium do — was the first real test of whether the periodic table keeps working this far out. It also began the Transfermium Wars, a twenty-year dispute between Berkeley and Dubna over who had discovered what, which IUPAC only settled in 1997 by handing out names in a package deal. Berkeley wanted to call it rutherfordium, Dubna wanted kurchatovium, and for decades Soviet and Western textbooks printed different periodic tables.

## Properties

- **Atomic number:** 104
- **Symbol:** Rf
- **Mass number of most stable isotope:** [267]
- **Category:** Transition metal
- **Group:** 4
- **Period:** 7
- **Block:** d-block
- **Electron configuration:** [Rn] 7s² 5f¹⁴ 6d²
- **Electrons per shell:** 2, 8, 18, 32, 32, 10, 2
- **Oxidation states:** +4
- **Discovered:** 1964 by Dubna, with independent work at Berkeley in 1969; IUPAC credited both

## Electron configuration

- **Full:** 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶ 7s² 5f¹⁴ 6d²
- **Noble gas shorthand:** [Rn] 7s² 5f¹⁴ 6d²
- **Shells:** K: 2 · L: 8 · M: 18 · N: 32 · O: 32 · P: 10 · Q: 2

## What it is used for

- Research only; no application outside the laboratory

## Hazards

- Intensely radioactive; exists only as individual atoms in an accelerator

> Melting point, boiling point, density and electronegativity are omitted: no measurement is possible on the quantities that exist. The mass given is the mass number of rutherfordium-267, the longest-lived at roughly 1.3 hours.

> Several physical properties are not listed for rutherfordium because no bulk sample has ever existed. Only a handful of atoms have been produced, often with half-lives measured in seconds, so published melting points and densities for elements in this range are calculations rather than measurements. They are omitted rather than presented as observed values.

## Neighbours in the table

| Z | Element | Symbol | Mass |
| --- | --- | --- | --- |
| 102 | Nobelium | No | [259] |
| 103 | Lawrencium | Lr | [266] |
| 104 | Rutherfordium ← | Rf | [267] |
| 105 | Dubnium | Db | [268] |
| 106 | Seaborgium | Sg | [269] |

## Group 4

Elements in the same group share their outer electron count, which is why they behave similarly in reactions. Rutherfordium sits in group 4 with titanium, zirconium, hafnium.

## Common questions

### What is the atomic number of rutherfordium?

104. That is the number of protons in its nucleus, which is what defines the element.

### What is the symbol for rutherfordium?

Rf.

### What is the electron configuration of rutherfordium?

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶ 7s² 5f¹⁴ 6d², or [Rn] 7s² 5f¹⁴ 6d² in noble-gas shorthand.

## Related pages

- [Nobelium (No)](https://atoneplace.net/element/nobelium/)
- [Lawrencium (Lr)](https://atoneplace.net/element/lawrencium/)
- [Dubnium (Db)](https://atoneplace.net/element/dubnium/)
- [Seaborgium (Sg)](https://atoneplace.net/element/seaborgium/)
- [Titanium (Ti)](https://atoneplace.net/element/titanium/)
- [Zirconium (Zr)](https://atoneplace.net/element/zirconium/)
- [Hafnium (Hf)](https://atoneplace.net/element/hafnium/)

## Sources

- Typical range compiled from manufacturer specifications — At One Place (/about/)