Introduction
Helium (He) is a colourless, odourless, tasteless, non-toxic and chemically inert noble gas belonging to Group 18 of the periodic table. It is the second lightest element after hydrogen and the second most abundant element in the universe, primarily formed through nuclear fusion in stars.
On Earth, helium is relatively rare and is mainly obtained from natural gas fields, where it accumulates due to the radioactive decay of uranium and thorium in the Earth’s crust.
- Atomic Number: 2
- Atomic Mass: 4.0026 u
- Electronic Configuration: 1s²
- Symbol: He
Occurrence
In the Universe
- Second most abundant element after hydrogen.
- Constitutes about 24% of the observable universe’s mass.
- Produced through nuclear fusion inside stars.
On Earth
Helium is found in:
- Natural gas reserves (commercial source)
- Trace amounts in the atmosphere (~5.2 ppm)
- Radioactive mineral deposits
Major global producers include the United States, Qatar and Algeria.
Properties
- Colourless, odourless and tasteless.
- Chemically inert due to a complete outer electron shell.
- Non-flammable and non-explosive.
- Lowest boiling point of any element (−268.93°C or 4.22 K).
- Does not solidify under normal atmospheric pressure, even at absolute zero.
- Very low density, making it lighter than air.
- High thermal conductivity.
- High diffusivity and low solubility in water.
Isotopes
Helium has two naturally occurring stable isotopes:
- Helium-3 (³He): Rare isotope; important in cryogenics, neutron detection and potential future nuclear fusion research.
- Helium-4 (⁴He): Most abundant isotope, produced through alpha decay of radioactive elements.
Uses
Cryogenics
Liquid helium is the coldest known cryogenic liquid and is used to cool superconducting magnets in:
- MRI machines
- NMR spectrometers
- Particle accelerators (e.g., CERN’s Large Hadron Collider)
Space and Defence
Used for:
- Pressurising rocket fuel tanks.
- Purging fuel systems.
- Cooling space instruments.
- Aerospace research.
Medical Applications
- MRI cooling systems.
- Heliox (helium-oxygen mixture) for treating respiratory disorders.
- Cryosurgery.
Industrial Applications
- Arc welding (shielding gas).
- Semiconductor and fibre-optic manufacturing.
- Leak detection in pipelines and vacuum systems.
- Controlled atmospheres in industrial processes.
Scientific Research
- Low-temperature physics.
- Quantum mechanics experiments.
- Superconductivity research.
Aviation
Helium is used to fill:
- Weather balloons.
- Scientific research balloons.
- Airships and blimps.
It is preferred over hydrogen because it is non-flammable.
Importance
Helium is considered a strategic resource due to its irreplaceable role in:
- Healthcare
- Defence
- Space exploration
- Scientific research
- Electronics manufacturing
- Nuclear technology
Since helium cannot be artificially manufactured economically on a large scale, conservation and efficient use are essential.
Challenges
Limited Availability
Helium is a non-renewable resource on human timescales. Once released into the atmosphere, it escapes into outer space due to its low atomic mass.
Global Supply Constraints
Production is concentrated in a few countries, making supply vulnerable to geopolitical disruptions and production outages.
Rising Demand
Growing demand from healthcare, semiconductor manufacturing, space programmes and research has increased concerns over future shortages.
Helium in India
- India has limited commercial helium reserves.
- Significant traces of helium have been identified in natural gas fields, particularly in Rajasthan.
- The Council of Scientific and Industrial Research (CSIR) has explored helium-rich gas reserves in the Bakreswar–Tantloi geothermal region (West Bengal–Jharkhand).
- India primarily relies on imports to meet its helium requirements for medical, scientific and industrial purposes.
Conclusion
Helium is a unique and strategically important noble gas with indispensable applications in medicine, scientific research, defence, aerospace and advanced manufacturing. Although abundant in the universe, it is scarce and non-renewable on Earth. Ensuring sustainable exploration, efficient utilisation and recycling of helium will be crucial for meeting future technological and industrial demands.
