Multidimensional structural design of pioneer oxide ceramics with melting points above 3000 °C

Thermal protective materials that remain stable above 3000 °C are crucial for hypersonic vehicles and nuclear fusion systems, yet reported nonradioactive oxides melt below this threshold. Zhou et al. demonstrated a cation engineering strategy that couples crystallographic symmetry, the coordination number, the valence electron concentration (VEC), the cation radius, and metal‒oxygen bonding to increase the melting temperature of fluorite-type oxides. Guided by the above multidimensional design framework, Ta-doped HfO₂ was experimentally validated to have a melting point surpassing 3000 °C, which was confirmed as the first nonradioactive oxide with a melting point above 3000 °C. This perspective distills the underlying symmetry–VEC–bonding design principles and discusses how they can guide the discovery and engineering integration of ultrahigh-temperature oxide ceramics.