Vanadium

Vanadium is a hard, silvery-grey metal whose most remarkable feature is its extraordinarily colourful chemistry. Its compounds come in brilliant shades of violet, blue, green and yellow, and it plays a hidden but vital role in making some of the world's strongest steel alloys used in car chassis, bridges and tools.

  • Atomic Number2323 protons, 23 electrons
  • Atomic Mass50.9415 uAbout 51× heavier than hydrogen
  • State at Room TempSolidsilvery-grey hard metal
  • Density6.0 g/cm³Slightly denser than titanium
  • Melting / Boiling1909.8°C / 3406.8°CMelts at 1,910°C
  • Discovered1801Nils Gabriel Sefström, 1831

How does vanadium sit among its Period 4 neighbours?

Vanadium sits between titanium and chromium in Period 4, steadily increasing in mass.

Atomic Mass Comparison
Titanium47.9 u
Vanadium50.9 u
Chromium52.0 u
Manganese54.9 u
Iron55.8 u

Vanadium at 50.9 u sits snugly between titanium (47.9 u) and chromium (52 u) in the first transition metal row. The steady increase reflects the gradual filling of the 3d electron subshell across Period 4.

What is vanadium?

Vanadium is a transition metal in Group 5 of the periodic table. It has 23 protons and can exist in five different oxidation states, from +2 to +5, each producing a distinctly different colour in solution. This range of oxidation states is what makes vanadium both beautiful to chemists and useful in electrochemical applications. Pure vanadium metal is hard and resistant to corrosion by alkalis and most non-oxidising acids.

Vanadium is named after Vanadis, another name for the Norse goddess Freyja, goddess of beauty, chosen because of the element's beautifully coloured compounds. The Swedish chemist Nils Gabriel Sefström rediscovered it in 1831, though it had first been found (and lost) much earlier. The symbol V comes from the name.

Fact Vanadium compounds cycle through four beautiful colours as the oxidation state changes. Add a reducing agent to yellow vanadium(V) solution and it turns blue (V(IV)), then green (V(III)), then violet (V(II)), a colour change that can be done step by step in a test tube, producing a rainbow of colours from a single element.

Where you find vanadium

On Earth

Vanadium is the 20th most abundant element in the Earth's crust, but like titanium and scandium, it is spread thinly and never concentrated in rich single-element deposits.

  • Vanadinite and patronite. These are the primary vanadium minerals. Major deposits of vanadium-bearing rocks are found in China, Russia, South Africa and Brazil.
  • Steel slag. Most commercial vanadium is recovered as a by-product of processing steel from vanadium-containing iron ore, particularly from deposits in South Africa and China.
  • Fossil fuels. Crude oil and coal contain small amounts of vanadium compounds. Some vanadium is recovered from processing petroleum.

How we use vanadium

  • High-strength steel. About 85% of all vanadium goes into making High Strength Low Alloy (HSLA) steels. Just a small addition of vanadium dramatically strengthens steel, allowing lighter but stronger car frames, bridges, tools and reinforcing rods.
  • Vanadium redox flow batteries. Large-scale energy storage batteries using vanadium solutions are increasingly used to store electricity from wind and solar farms. They can be charged and discharged thousands of times without degrading.
  • Catalysis. Vanadium pentoxide (V₂O₅) is the key catalyst in the contact process for making sulfuric acid: the world's most produced industrial chemical.
  • Titanium alloys. Vanadium is a key component of the most widely used titanium alloy, Ti-6Al-4V, used in aircraft and medical implants.
Did you know? Sea squirts, strange, filter-feeding sea creatures that look like blobs attached to rocks, concentrate vanadium in their blood at levels up to 10 million times higher than the surrounding seawater. The function of this concentrated vanadium is still not fully understood, but it may play a role in their immune systems or in hardening their outer coating.

How it was discovered

Vanadium has a complicated discovery history. It was first identified in 1801 by the Spanish mineralogist Andrés Manuel del Río in Mexico, who called it erythronium. But he was persuaded by colleagues that it was impure chromium and withdrew his claim. In 1831, the Swedish chemist Nils Gabriel Sefström rediscovered it in iron ore and recognised it as a new element, naming it vanadium. Friedrich Wöhler then confirmed that del Río's erythronium was indeed the same element, but Sefström's name stuck. The pure metal was not isolated until 1867.

Deeper dive: vanadium steel and the redox flow battery

Henry Ford heard about vanadium steel while inspecting a crashed French racing car and decided he wanted it for the Model T. Ford commissioned the development of vanadium steel in the USA, and the 1908 Model T became the first mass-produced car to use it for critical components like the crankshaft and axles. The steel was significantly stronger and lighter than anything Ford had used before, a pivotal moment in automotive history.

Vanadium redox flow batteries (VRFBs) are among the most promising technologies for grid-scale energy storage. Unlike conventional batteries, which store energy in solid electrodes, VRFBs store it in two tanks of liquid vanadium solutions. During charging and discharging, the vanadium ions change oxidation state, on one side from V(IV) to V(V), and on the other from V(III) to V(II). The advantage is that the storage capacity can be increased simply by using bigger tanks, without changing the rest of the battery. VRFBs can be charged and discharged over 20,000 times without significant degradation.

Vanadium is a colourful and multifaceted element, from rainbow-coloured laboratory chemistry to the steel in your car frame. Moving to 24 protons brings us to chromium, the metal that makes stainless steel stainless.