NEW MEXICO DESERT — An international research team coordinated by geologist Luca Bindi has identified a previously unknown calcium-copper-silicon type I clathrate within a copper-rich metal droplet embedded in red trinitite from the Trinity nuclear test. The material had never before been observed in nature or created artificially in a laboratory.

The Trinity test, conducted on July 16, 1945, in the New Mexico desert, was the world's first test of an atomic bomb. Red trinitite is a glassy residue formed from the desert sand and surrounding materials fused by the detonation.

The researchers used x-ray diffraction to identify the type I clathrate in the trinitite sample. They said the new material formed spontaneously during the nuclear explosion, noting that the extreme temperatures and pressures generated by such detonations can produce materials impossible to obtain by traditional methods.

The discovery follows earlier work by the same team. A few years ago, the group led by Bindi documented a silicon-rich quasicrystal that also formed during the Trinity nuclear test. A quasicrystal is a material with a non-periodic atomic arrangement that creates symmetries leading to physical properties that are difficult to predict.

"Their peculiarity is that the atomic arrangement that is not periodic, but nearly so, creates incredible symmetries from which derive amazing physical properties, among other things, very difficult to predict," Bindi said of quasicrystals. Events such as nuclear explosions, lightning strikes, and meteoritic impacts function as natural laboratories that allow observation of forms of matter not easily reproduced in the laboratory.

Clathrates are materials characterized by a cage-like structure that traps other atoms and molecules inside. They are being studied for applications including energy conversion, new semiconductors, gas storage, and hydrogen storage technologies.