Researchers have overturned long-held assumptions about the metal gallium after finding that its covalent bonds reform at high temperatures. The discovery, made at the University of Auckland, explains the element's unusually low melting point.
Gallium was discovered in 1875 by French chemist Paul Émile Lecoq de Boisbaudran. For decades scientists believed its covalent bonds vanished upon melting, yet new measurements show the bonds return when the liquid is heated further.
The study was led by Dr. Steph Lambie during her PhD at the University of Auckland, working with Professor Nicola Gaston and Dr. Krista Steenbergen. They reviewed decades of published data collected at varying temperatures to build a clearer picture of the metal's structure.
Professor Nicola Gaston stated that thirty years of literature on liquid gallium rested on an assumption now shown to be untrue. The findings were published in Materials Horizons under the title "Resolving Decades of Debate: The Surprising Role of High-Temperature Covalency in the Structure of Liquid Gallium."
Gallium is used in semiconductors, LEDs, solar panels, and aerospace applications. A revised understanding of its temperature-dependent behavior may support advances in nanotechnology and liquid-metal engineering.