ELEMENTLE

Element 44 · Transition Metal

Ruthenium

Period 5 · Group 8

Ruthenium is a chemical element with symbol Ru and atomic number 44. It is a rare transition metal belonging to the platinum group of the periodic table. Like the other metals of the platinum group, ruthenium is inert to most other chemicals.

Three reasons Ruthenium stands out

  1. 1

    Used in electronics and jewelry.

  2. 2

    It is one of the rarest precious metals on Earth, far scarcer than gold or platinum.

  3. 3

    It is being actively researched as a potential alternative to platinum in cancer-fighting drugs.

A hard metal from the platinum family

Ruthenium is a scarce, hard metal usually recovered while refining platinum ores. Minute additions can harden platinum and palladium, while ruthenium compounds catalyze useful chemical reactions. Its conductive oxides appear in electronic components, linking rare-metal refining to everyday circuitry.

Ruthenium at a glance
Atomic number / protons44
SymbolRu
Family (Elementle)Transition Metal
Classification (PubChem)Transition metal
Period5
Group8
Atomic mass (u)101.1
Standard stateSolid
Electron configuration[Kr]5s1 4d7
Reported oxidation states+3
Electronegativity (Pauling)2.2
Atomic radius (pm)207
First ionization energy (eV)7.361
Electron affinity (eV)1.05
Density (g/cm³)12.1
Melting point2607 K (2,333.85 °C)
Boiling point4423 K (4,149.85 °C)
Discovery (PubChem)1827

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: Ruthenium · Ruthenium 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.