Beryllium Be

Discovery

In 1798 the French chemist Louis-Nicolas Vauquelin was asked by the mineralogist René Just Haüy to compare beryl and emerald, which Haüy suspected were the same mineral. Vauquelin found that both contained a previously unknown oxide, which he called an 'earth'. The discovery confirmed that emerald is simply a green variety of beryl.

The metal itself was isolated thirty years later, in 1828, when Friedrich Wöhler in Germany and Antoine Bussy in France independently reduced beryllium chloride with potassium. Industrial production began in the twentieth century, and beryllium–copper alloys became common from the 1930s.

Origin of the name

The element is named after the mineral beryl, from the Greek beryllos, a word used for blue-green gemstones. The editors of the journal that published Vauquelin's work called the oxide 'glucina' because some beryllium salts taste sweet, and the name glucinium was used in France for over a century before 'beryllium' was adopted internationally. The symbol is Be.

Main uses

• Aerospace and defence: its stiffness-to-weight ratio suits satellite structures, precision gyroscopes and lightweight mirrors. The primary mirror segments of the James Webb Space Telescope are made of gold-coated beryllium.
• X-ray windows: thin beryllium foil lets X-rays pass while keeping out air and light, so it is used in X-ray tubes and detectors.
• Alloys: a few percent of beryllium turns copper into a strong, springy, non-sparking alloy used in tools for explosive environments, connectors and springs.
• Nuclear technology: beryllium reflects and moderates neutrons and serves as a neutron source when mixed with alpha emitters.

Isotopes

Beryllium has only one stable isotope, beryllium-9, so natural beryllium is essentially a single nuclide. Beryllium-10, with a half-life of about 1.4 million years, is produced when cosmic rays strike atmospheric nitrogen and oxygen. Geologists measure it in ice cores, sediments and rock surfaces to estimate exposure ages and erosion rates. Beryllium-7, with a half-life of about 53 days, is also made by cosmic rays and is used to trace air masses. Beryllium-8 falls apart almost instantly into two helium nuclei, which is why stars must fuse three helium nuclei at once to make carbon.

In everyday life

Solid beryllium objects are safe to handle, but inhaling beryllium dust or fumes can cause chronic beryllium disease, a serious lung condition that may appear years after exposure in sensitised people. Workplaces that machine beryllium therefore use enclosed processes and air monitoring.

The element is rare in the Earth's crust. The gemstones emerald and aquamarine are both varieties of beryl, coloured by traces of chromium or vanadium and iron respectively.