Yttrium

Yttrium is a silvery metal with a remarkable distinction: it gave its name to a village in Sweden that in turn gave its name to four separate chemical elements. Today yttrium is inside the LED backlights of most flat-screen displays, in the superconductors that levitate maglev trains, and in medical lasers used for eye surgery and cancer treatment.

  • Atomic Number3939 protons, 39 electrons
  • Atomic Mass88.90584 uAbout 89× heavier than hydrogen
  • State at Room TempSolidsilvery-white metal
  • Density4.47 g/cm³About 4.5× denser than water
  • Melting / Boiling1521.8°C / 3344.8°CMelts at 1,522°C
  • Discovered1794Johan Gadolin, 1794

Yttrium opens the second row of transition metals in Period 5.

It sits below scandium and above lanthanum as the lightest Group 3 element of Period 5.

Atomic Mass Comparison
Strontium87.6 u
Yttrium88.9 u
Zirconium91.2 u
Iron55.8 u
Barium137 u

Yttrium (88.9 u) is closely spaced in mass between strontium (87.6 u) and zirconium (91.2 u), opening the second row of transition metals. Like scandium, yttrium primarily forms +3 compounds and is often classified with the rare earth elements despite not being a lanthanide.

What is yttrium?

Yttrium is a transition metal in Group 3 of the periodic table, sitting below scandium and in the same period as the lanthanide rare earths. It has 39 protons and typically forms +3 compounds. Despite technically being a transition metal, yttrium is usually grouped with the rare earth elements because its chemistry is nearly identical to that of the lanthanides, it invariably occurs with them in ores and is separated from them with the same techniques. It is a malleable, silvery metal that is relatively stable in air.

Yttrium is named after the village of Ytterby near Stockholm in Sweden. In 1787, Lieutenant Carl Axel Arrhenius found a dark, heavy mineral there that he sent to chemists for analysis. The mineral turned out to contain an extraordinary mixture of rare earth elements, and was eventually found to contain no fewer than seven new elements, four of which (yttrium, ytterbium, terbium and erbium) are directly named after the village. This makes Ytterby, a small quarry site, the most fruitful single location in the history of elemental discovery.

Fact A single small quarry near Ytterby, Sweden, gave its name to four chemical elements: yttrium (Y), ytterbium (Yb), terbium (Tb) and erbium (Er). This tiny location contributed more named elements to the periodic table than any other place on Earth, a remarkable tribute to the complexity of the rare earth minerals found there in the late 18th century.

Where you find yttrium

On Earth

Yttrium is moderately abundant in the Earth's crust, approx. 33 parts per million, and is always found alongside the rare earth elements in mineral deposits.

  • Monazite and xenotime. The main yttrium-bearing minerals, found in placer deposits (concentrated by river and beach erosion) in China, Malaysia, Australia and India.
  • Bastnäsite. A rare earth fluorocarbonate mineral that is the world's main source of rare earths; yttrium is a significant component.
  • China dominates. China produces over 80% of the world's yttrium, as part of its dominant position in rare earth element supply.

How we use yttrium

  • LED phosphors. Yttrium aluminium garnet (YAG) doped with cerium is a yellow phosphor used in white LEDs: the blue LED chip excites the YAG phosphor, which emits a broad yellow light that combines with the remaining blue to appear white to human eyes.
  • Superconductors. Yttrium barium copper oxide (YBCO or "1-2-3 superconductor") was the first material to superconducting above the temperature of liquid nitrogen (−196°C), a landmark discovery in 1987 that opened up practical applications of high-temperature superconductivity.
  • Medical lasers. YAG lasers (yttrium aluminium garnet) doped with neodymium are used for eye surgery, treating certain cancers and cutting kidney stones without the need for traditional surgery.
  • Strengthening alloys. Small amounts of yttrium improve the high-temperature strength and oxidation resistance of nickel-based superalloys used in jet engines.
Did you know? Yttrium barium copper oxide (YBCO) is a "warm" superconductor that loses all electrical resistance at temperatures above the boiling point of liquid nitrogen (−196°C). This was a revolutionary discovery in 1987 because liquid nitrogen is cheap and widely available, unlike liquid helium needed for older superconductors. YBCO superconductors are used in MRI machines, research magnets and experimental maglev transport systems.

How it was discovered

Yttrium was discovered in 1794 by the Finnish chemist Johan Gadolin, who analysed the dark, heavy mineral found at Ytterby (later named gadolinite in his honour) and identified a new oxide he called yttria. He could not isolate the metal. The pure element was finally obtained in an impure form in 1828 by Friedrich Wöhler, and reasonably pure yttrium metal was not available until the 1950s, when ion exchange techniques were developed to separate rare earth elements from one another.

Deeper dive: rare earth elements and yttrium superconductors

Yttrium is chemically almost identical to the lanthanide rare earths. All of them form +3 ions of similar sizes, which means they invariably occur together in nature and are extremely difficult to separate. The development of ion exchange chromatography in the 1940s-50s was the key breakthrough that allowed rare earth elements to be separated from each other in quantity, making yttrium and other rare earths available at reasonable cost for industrial use.

The discovery of high-temperature superconductivity in YBCO in 1987 by Georg Bednorz and K. Alex Müller (who received the 1987 Nobel Prize in Physics, awarded in record time) was one of the most exciting scientific events of the 20th century. At −183°C, YBCO loses all electrical resistance and expels magnetic fields (the Meissner effect), allowing magnets to levitate above it. Practical applications of YBCO include the superconducting magnets in MRI machines (which can be built without liquid helium), high-sensitivity magnetic sensors, and prototype maglev trains.

Yttrium is a quiet element that enables brilliant white LED light and remarkable superconducting technology. Moving to 40 protons brings us to zirconium, a metal almost identical to hafnium in appearance but strikingly different in its nuclear properties.