Vanadium
[Ar] 3d³ 4s² · 2 · 8 · 11 · 2
A hard steel-grey metal famous for the rainbow of its solutions: oxidation states from +2 to +5 give violet, green, blue and yellow. Nearly all the vanadium mined goes into steel.
3D model
Bohr model: nucleus and electron shells from the real configuration. Valence electrons are highlighted.
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Atomic properties
- Atomic number
- 23
- Atomic mass
- 50.942 а.е.м.
- Electron configuration
- [Ar] 3d³ 4s²
- Electrons per shell
- 2 · 8 · 11 · 2
- Block
- d-block
- Group
- Vanadium group
- Period
- 4
- Electronegativity (Pauling)
- 1.63
- Electronegativity (Allen)
- 1.53
- Atomic radius
- 171 pm
- Covalent radius
- 153 pm
- Van der Waals radius
- 179 pm
- Ionisation energy 1
- 650.9 kJ/mol
- Ionisation energy 2
- 1 414 kJ/mol
- Ionisation energy 3
- 2 830 kJ/mol
- Ionisation energy 4
- 4 507 kJ/mol
- Ionisation energy 5
- 6 298.7 kJ/mol
- Electron affinity
- 50.6 kJ/mol
- Common oxidation states
- +5
- Oxidation states
- -3, -1, +1, +2, +3, +4, +5
Physical properties
- State at 25 °C
- solid
- Density
- 6.11 g/cm³
- Melting point
- 2 183 K · 1 909.9 °C
- Boiling point
- 3 680 K · 3 406.9 °C
- Speed of sound
- 4 560 m/s
Thermal properties
- Heat of fusion
- 21.5 kJ/mol
- Heat of vaporisation
- 444 kJ/mol
- Specific heat capacity
- 0.489 J/(g·K)
- Thermal conductivity
- 30.7 W/(m·K)
Mechanical properties
- Young's modulus
- 128 GPa
- Shear modulus
- 47 GPa
- Bulk modulus
- 160 GPa
- Poisson ratio
- 0.37
- Mohs hardness
- 6.7
- Brinell hardness
- 628 MPa
Electrical and magnetic properties
- Electrical resistivity
- 197 nΩ·m
- Magnetic ordering
- paramagnetic
- Curie point
- no data
- Néel point
- no data
- Superconducting point
- 5.4 K
Crystal structure
- Crystal structure
- body-centred cubic (bcc)
- Lattice constants
- a = 303 pm
Abundance
- In the crust
- 120 mg/kg
- In the ocean
- 0.0025 mg/L
- In the universe
- 1 000 mg/kg
- In the human body
- 0.00026 mg/kg
Isotopes
| Isotope | Abundance | Half-life | Decay mode |
|---|---|---|---|
| 50V | 0.25 % | 2.694·10⁸ Gyr | ЭЗ |
| 51V | 99.75 % | stable | — |
Vanadium-50 is formally radioactive, but its half-life exceeds 10¹⁷ years — it is stable for any practical purpose.
Discovery
- Year of discovery
- 1801
- Discovered by
- Andrés Manuel del Río
- Where
- Mexico
- Origin of the name
- after Vanadis, Norse goddess of beauty, for the vivid colours of its compounds
History
Andrés del Río found the element in Mexican lead ore in 1801 but withdrew the claim after doubting himself. Thirty years later Nils Sefström rediscovered it in Sweden and named it after Vanadis, the Norse goddess of beauty.
Where it occurs
120 mg/kg of the crust, dispersed in titanomagnetites, phosphorites and heavy crude oil. Rich ores of its own barely exist.
How it is produced
Mostly as a by-product: from the slags of vanadium-bearing iron ores and from ash left by burning heavy oil residues.
Role in living things
Some algae and sea squirts require vanadium; sea squirts concentrate it in their blood a million times above seawater, and nobody yet knows why. For humans no role is established.
Safety
Vanadium pentoxide is toxic on inhalation and irritates the airways; chronic exposure causes bronchitis.
Uses
- Alloying steel: 0.15 % vanadium markedly raises the strength and wear resistance of tools and rebar
- Vanadium pentoxide as the catalyst in contact-process sulfuric acid
- Vanadium redox flow batteries for grid storage
- Titanium–vanadium alloys in aviation
Curiosities
- Vanadium solutions in four oxidation states give four different colours, a classic lecture demonstration.
- The goddess of beauty lent her name precisely because of that palette.
- Vanadium tool steel holds a cutting edge many times longer than plain carbon steel.
- A vanadium flow battery uses the same element in both electrolytes, so cross-contamination cannot degrade it.