The atomic bombing of Hiroshima, Japan, on August 6, 1945, created a complex alloy that has never been seen before. Researchers recently discovered the crystalline alloy within tiny glass particles collected from the beach sands of Hiroshima Bay (Sci. Adv. 2026, DOI: 10.1126/sciadv.aeg8299).
The alloy is a silicon-rich crystal containing six metals—iron, chromium, nickel, manganese, molybdenum, and aluminum—and has an ordered AlAu₄-type crystal structure. This combination of composition and crystal structure has never before been documented, says Luca Bindi, a geologist at the University of Florence and first author on the new paper.
Nuclear blasts wreak destruction—including about 100,000 deaths in the Hiroshima attack. But they also become crucibles that forge new materials. The extreme temperatures and rapid pressure fluctuations vaporize matter, which then cools rapidly, resulting in unusual structures.
A well-known example is trinitite, a glassy aggregate made from the fusion of sand, metals, and radioactive residues from the Trinity nuclear test in the New Mexico desert on July 16, 1945. Bindi and colleagues have recently found that the Trinity test also created a clathrate compound made of calcium, copper, and silicon (Proc. Natl. Acad. Sci. U.S.A. 2026, DOI: 10.1073/pnas.2604165123).
But the atomic blasts at Hiroshima and Nagasaki, Japan, were unique settings for material formation. “Hiroshima . . . was an airburst over a complex urban environment,” Bindi says. The fireball reached temperatures over 7,000 °C within seconds, vaporizing “mixed building materials, metals, glass, soil, and atmospheric components,” he says.
This spherical glassy particle (left) is a piece of debris from the atomic blast in Hiroshima, Japan. Researchers found a novel alloy in a metallic grain in the particle; the reflected light image on the right shows metallic content in the particle. Credit:
Sci. Adv.
That mix led to the creation of novel materials. In 2019, retired geologist Mario Wannier found tiny glass particles when he was combing through beach sands from Hiroshima Bay. The particles, dubbed hiroshimaite, turned out to be fallout debris from the atomic blast.
Akin to finding a needle in a haystack, Wannier, Bindi, and colleagues have now discovered a new alloy inside one of these particles. The team examined 34 bits of hiroshimaite ranging in width from a few hundred micrometers to a few millimeters and found several metallic crystals in one of them.
Chemical analysis of those metallic crystals showed one silicon-rich grain, just 10 µm long. The researchers extracted the grain and used single-crystal X-ray diffraction to identify the new multicomponent alloy. “Only one grain of the new alloy was found, so it appears to be rare,” Bindi says.
Serendipitous findings such as this one quite often “open up entirely new research directions and deepen our understanding of how materials form and behave,” says Ángelo Oñate Soto, a materials scientist and engineer at the University of Concepción, who wasn’t involved in the new work. There is a growing interest in multicomponent alloys—mixtures with large fractions of each metal, rather than a base metal mixed with small amounts of others. These materials can have “properties that are difficult, or even impossible, to achieve using conventional alloys,” he says, such as outstanding mechanical strength, corrosion resistance, and temperature stability.
But making such alloys is not easy in the laboratory. They have to be engineered using carefully controlled metallurgical processes. “So letting a bomb randomly explore the combinations of all the elements that might be swept up in vaporizing a city is a rather different approach to a massively parallel search of composition space,” says Paul D. Asimow, a geologist and geochemist at the California Institute of Technology, who also wasn’t involved in this work.
The exact conditions in which the new alloy was forged are unknown. So reproducing it would be a significant scientific challenge but also an opportunity. “The nuclear explosion is so exotic that it can make things we’ve never seen before, but that isn’t much use technologically unless we can find a different and more efficient way to reach the same end product,” Asimow says. “Of course, we wouldn’t even try to reach that end product if we didn’t know it existed.”
Prachi Patel is a senior editor and physical sciences reporter at C&EN based in Pittsburgh.
