Ruthenium (Ru)

Hard, silvery metal

Ruthenium is a rare platinum metal used in electronics, hard disk drives, and solar energy conversion, and with [Kr] 4d⁷ 5s¹, ruthenium exhibits oxidation states from 0 to +8. It is used as a catalyst in olefin metathesis (Grubbs catalyst) and in dye-sensitized solar cells where it absorbs visible light.

Key metrics

Density12.45g/cm³

Melting point2,607K

Boiling point4,423K

Electronegativity2.2Pauling

Discovery

1844discovered

Discovered by: Karl Ernst Claus
Reactivity profile: Chemically inert
Reactivity: Low
Bonding: Metallic

Electron configuration

\textcolor{#6b7280}{[Kr]}\; \textcolor{#22c55e}{4_{d}^{7}}\; \textcolor{#ef4444}{5_{s}^{1}}

[Kr] 4d7 5s1

Wave function

\Psi_{\text{Ru}} \approx \frac{1}{\sqrt{44!}} \det \left| \chi_1(\mathbf{r}_1) \dots \chi_{44}(\mathbf{r}_{44}) \right|

Probability density $|\Psi|^2$ across the Ru valence shell.

Crystal structure

Hexagonal Close-Packed

Lattice constantsa 1.00 · b 1.00 · c 1.63

Cell anglesα 90° · β 90° · γ 120°

Coordination number12

Atoms per cell2

Atomic packing factor0.74

Physical properties

Atomic radius: 134 pm
Ionization energy: 710 kJ/mol
Electron affinity: 101 kJ/mol
Crystal structure: Hexagonal close-packed (hcp)

Oxidation states

+2+3+4+6+8

Acid/base

Can act as acid or base

Strongly acidicStrongly basic

State at 25 °CSolid

2607 K4423 K298 K

Emission spectrum

3 transitions

380450500550600650700780

VioletBlueGreenYellowRed

372.8nmRu I (UV)UV50%

438.0nmRu I (blue)Violet100%

475.8nmRu IBlue70%

Dominant line 438.0 nmRange 373–476 nmTransitions 3