Ru
Ruthenium
Element 44 · Transition metal
Ruthenium (Ru)
Ruthenium is a hard, rare platinum-group metal. It does not tarnish and is used to harden platinum and palladium.
- Transition metal
- Period 5
- Group 8
- d-block
- solid at room temperature
Key properties
- Atomic mass
- 101.1
- u
- Electron configuration
- [Kr] 4d7 5s1
- Melting point
- 2,333.9 °C
- 2,607 K
- Boiling point
- 4,149.9 °C
- 4,423 K
- Density
- 12.1 g/cm³
- Electronegativity
- 2.2
- Pauling
- Atomic radius
- 207 pm
- van der Waals
- 1st ionisation energy
- 7.361 eV
Compare with every element:Electronegativity chartAtomic radius chartIonisation energy chartDensity chart of the elementsMelting point chartElectron configuration chart
Did you know?
Notable facts about ruthenium
- 01
Ruthenium is one of the rarest metals in Earth’s crust.
- 02
It is used in the thin films of computer hard-disk drives.
- 03
Ruthenium dyes are used in experimental dye-sensitised solar cells.
Applications
What is ruthenium used for?
- Hard disk drives
- Electrical contacts
- Catalysts
- Hardening platinum jewellery
History
Discovery & name origin
Atomic structure
Atomic properties
Atomic structure
Atomic properties
- Atomic number
- 44
- Atomic mass
- 101.1 u
- Group
- 8
- Period
- 5
- Block
- d-block
- Electron configuration
- [Kr] 4d7 5s1
- Full configuration
- 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s1 4d7
- Electrons per shell
- 2, 8, 18, 15, 1
- Electronegativity (Pauling)
- 2.2
- Electron affinity
- 1.05 eV
- Atomic radius (van der Waals)
- 207 pm
- Stable isotopes
- 7
Oxidation states
Highlighted: common oxidation states (+3).
Successive ionisation energies
Energy to remove each electron in turn (kJ/mol). Big jumps show where a new, inner shell begins.
- 1st710.2
- 2nd1,620
- 3rd2,747
Physical
Physical properties & colour
Physical
Physical properties & colour
- State at 20 °C
- Solid
- Melting point
- 2,607 K · 2,333.9 °C · 4,232.9 °F
- Boiling point
- 4,423 K · 4,149.9 °C · 7,501.7 °F
- Density
- 12.1 g/cm³
- Molar heat capacity
- 24.06 J/(mol·K)
- Appearance
- Silvery white metallic
- CPK model colour
- Copied
The CPK colour is the convention used for this element’s atoms in molecular models.
FAQ
Ruthenium questions
What is Ru on the periodic table?
Ru is the symbol for ruthenium, element 44 on the periodic table. It sits in group 8, period 5, in the transition metal category, and has an atomic mass of 101.1.
What is the atomic number of ruthenium?
Ruthenium has atomic number 44, so every ruthenium atom has 44 protons in its nucleus. Its symbol is Ru and its atomic mass is 101.1.
Who discovered ruthenium?
Ruthenium was discovered by Karl Ernst Claus in 1844 (Russia). The name comes from Latin Ruthenia, “Russia”.
What is ruthenium used for?
Ruthenium is used for: hard disk drives; electrical contacts; catalysts; hardening platinum jewellery.
Is ruthenium a metal?
Yes. Ruthenium is a transition metal, one of the metallic elements.
What is the electron configuration of ruthenium?
The electron configuration of ruthenium is [Kr] 4d7 5s1. Its 44 electrons are arranged in shells as 2, 8, 18, 15, 1.