Researchers have recently discovered a new compound that combines helium with crystalline iron, a highly unusual combination due to helium’s unreactive nature. The compound was formed under extreme pressures through a process of compression that resulted in helium ions packing into the tiny spaces between iron atoms in a crystal structure. This discovery challenges the commonly held belief that helium does not typically form chemical compounds and expands the realm of noble gas chemistry.
The new iron-helium compound sheds light on the distribution of helium in Earth’s interior, particularly in the planet’s core. Most of the helium found on Earth is a result of the decay of radioactive elements like uranium, but there is also a reservoir of primordial helium with unique isotopic composition that dates back to the early universe. The presence of one-nucleon helium in oceanic volcanic eruptions hints at the possibility of primordial helium residing in Earth’s core, with the compound’s formation suggesting that the core could store some of this ancient helium.
Further experiments will be necessary to determine the likelihood of helium residing in Earth’s core or in its mantle, with the partitioning of helium between magma, silicate melt, and metallic iron being a key factor. If helium proves to be more stable in iron than in silicates, it could indicate a preference for the core as a storage site for the element. While the compound itself does not serve as definitive proof of helium’s presence in the core, it opens up possibilities for exploring new avenues of noble gas chemistry.
The implications of this discovery extend beyond geophysics, potentially paving the way for further research into helium metal compounds and transition metals. Chemists are interested in exploring whether similar compounds can be formed with other metals, leading to unexplored realms of chemistry. While the research has yet to provide conclusive evidence of helium in Earth’s core, it offers exciting prospects for expanding our understanding of chemical interactions involving noble gases and transition metals.
Overall, this groundbreaking research highlights the ability of helium, an otherwise unreactive element, to participate in unique forms of chemistry under extreme conditions. By coaxing helium into a compound with iron, scientists have opened a new chapter in the study of noble gas chemistry and its potential applications in understanding Earth’s composition and geological processes. The discovery not only challenges traditional notions of elemental reactivity but also sets the stage for further exploration into the chemistry of rare gases and their interactions with other elements.
