English translation of the original Chinese article. Publication dates and the extent of recovered text are preserved. Figures retain their original labels. Read the Chinese original.
Did you know? Helium’s name comes from helios, the Greek word for the Sun. In 1868, scientists observed a new yellow line in the solar spectrum that could not be explained by any element then known. This provided a clue to the discovery of helium. Humanity identified helium in the Sun before finding it on Earth.[1]
What Kind of Element Is Helium?
PhDSciNet answers: Helium is a noble gas with the chemical symbol He. Under ordinary conditions, it is a colorless, odorless gas, with a density higher only than that of hydrogen. Liquid helium-4, the common isotope, can become a superfluid below approximately 2.17 K, displaying extremely low resistance to flow and very high thermal conductivity. Superfluidity and superconductivity are different physical phenomena; liquid helium can be used to cool superconducting magnets.[1][2]
What Are Helium’s Chemical Properties?
PhDSciNet answers: Under ordinary conditions, helium is extremely unreactive and forms compounds only with great difficulty. Its stability is associated with its closed-shell electron configuration: the ground-state helium atom has the electron configuration 1s², filling its first electron shell.[1]
What Are the Uses of Helium Gas?
PhDSciNet answers: Because helium is very light and nonflammable, it can be used to fill airships and balloons. It is also used as a protective atmosphere in welding, optical-fiber production, and semiconductor manufacturing, and in helium–neon lasers. Liquid helium provides cryogenic cooling for superconducting magnets in magnetic-resonance equipment and accelerators.[1]
Can Helium Gas Harm the Human Body?
PhDSciNet answers: Helium itself is not generally considered a toxic gas, but inhaling large amounts of pure helium displaces oxygen, causing oxygen deprivation and, in severe cases, death. Inhaling directly from a high-pressure cylinder can also cause serious lung damage.[4]
How Is Helium Produced?
PhDSciNet answers: Helium on Earth mainly originates from the decay of radioactive elements. The alpha particles released are helium nuclei, which become helium atoms after capturing electrons. Some helium can accumulate in underground natural gas. Industry mainly extracts helium from helium-containing natural gas. Helium accounts for only about five parts per million of air by volume; because of this low concentration, extracting it from air is usually uneconomical. Helium entering the atmosphere also gradually escapes into space.[1]
A Helium–Sodium Compound under High Pressure
On February 6, 2017, the teams of 王慧田 and 周向峰 at Nankai University and their collaborators published research on a helium–sodium compound in Nature Chemistry. Combining theoretical predictions with high-pressure experiments, they found that Na₂He can be stable at pressures above 113 GPa. This result shows that helium can participate in forming stable compounds under specific extreme conditions; it cannot simply be described as never forming compounds under any conditions.[3]
References in the Original Manuscript
- Theodore Gray (United States). The Elements: A Visual Exploration of Every Known Atom in the Universe (color collector’s edition, Chinese edition). Posts & Telecom Press. Kindle Edition.
- 冯光熙, 黄祥玉. Inorganic Chemistry Series, Volume 1, section on noble gases. Science Press, fourth printing, March 2012.
- Baidu Baike: Helium (cited in the original manuscript).
- Xiao Dong, et al. Nature Chemistry 9, 440–445 (2017). DOI: 10.1038/nchem.2716.
- Wikipedia: Helium (historical webpage citation).
Sources for This Factual Revision
- Royal Society of Chemistry: Helium
- CERN: Cryogenics — Low temperatures, high performance
- Dong et al.: Author manuscript of the original paper on the high-pressure helium–sodium compound
- Missouri Poison Center: Helium
Editorial revision note: On October 10, 2026, the article was recovered from the local manuscript and historical webpage, with factual corrections. Superfluidity was distinguished from superconductivity; the descriptions of the discovery spectral line and high-pressure compound were corrected; and unverified sections on food packaging and resource prospects were removed. The historical publication date and byline are retained.
