Helium is named after Helios, the Titan of the Sun in Greek mythology. Helium was detected in the sun by its spectral lines many years before it was found on Earth.
Helium is a noble gas, colorless, odourless and completely unreactive. It is also non-toxic, non-flammable, lighter than air and has the lowest boiling point of all elements.
Lighter Than Air
Low Boiling Point (-268.9ºC)
High Melting Point (-272.2ºC)
High Thermal Conductivity
These properties make helium an ideal element for a rapidly growing range of innovative and advanced applications across industries.
Cooling – Medical (Cryogenics), Aerospace, and Nuclear Particle Research
Because it remains a gas at ultra low temperatures, helium is used as an optimal cooling medium. Helium is used in cooling the Large Hadron Collider (LHC) and the superconducting magnets in MRI scanners and NMR spectrometers. It is also used to keep satellite instruments cool and was used to cool the liquid oxygen and hydrogen that powered the Apollo space vehicles.
Because of its low density helium floats above air and is used to fill airships, weather balloons and decorative balloons. Hydrogen was once used to fill balloons but it is dangerously reactive.
Because it is very unreactive, helium is used to provide an inert protective atmosphere for making fibre optics and semiconductors, and for arc welding.
Helium is also used to detect leaks, such as in car air-conditioning systems, and because it diffuses quickly it is used to inflate car airbags after impact.
A mixture of 80% helium and 20% oxygen is used as an artificial atmosphere for deep-sea divers and others working under pressurised conditions.
Helium-neon gas lasers are used to scan barcodes in supermarket checkouts.
A new use for helium is a helium-ion microscope that gives better image resolution than a scanning electron microscope.
Occurrence and Production
After hydrogen, helium is the second most abundant element in the universe. It is present in all stars. On Earth it is formed from alpha-particle decay of radioactive elements in the Earth’s lithosphere (the crust and upper mantle).
Much of the helium formed escapes into the atmosphere, which contains about 5 parts per million by volume. This is a dynamic balance, with the low-density helium continually escaping to outer space.
Of the helium that remains in the Earth’s crust, the greatest natural concentrations are found in natural gas. It is uneconomical to extract helium from the air. Most commercial helium is extracted from natural gas, which can contain up to 7% helium.