Scientists computationally design new metastable, ultra-light crystalline form of aluminum

If you restructure aluminum at the molecular level, as Boldyrev and colleagues did using computational modeling, you could produce an ultra-light crystalline form of aluminum that’s lighter than water. Boldyrev, along with scientists Iliya Getmanskii, Vitaliy Koval, Rusian Minyaev and Vladimir Minkin of Southern Federal University in Rostov-on Don, Russia.

Above there is an image from Chemists from Utah State University, USA and Southern Federal University, Russia, showing computationally designed a new, metastable, ultra-light crystalline form of aluminum. Credit: Iliya Getmanskii, Southern Federal University, Russia

“My colleagues’ approach to this challenge was very innovative,” says Boldyrev, professor in USU’s Department of Chemistry and Biochemistry. “They started with a known crystal lattice, in this case, a diamond, and substituted every carbon atom with an aluminum tetrahedron.”

The team’s calculations confirmed such a structure is a new, metastable, lightweight form of crystal aluminum. And to their amazement, it has a density of only 0.61 gram per cubic centimeter, in contrast to convention aluminum’s density of 2.7 grams per cubic centimeter.

“That means the new crystallized form will float on water, which has a density of one gram per cubic centimeter,” Boldyrev says.

Such a property opens a whole new realm of possible applications for the non-magnetic, corrosive-resistant, abundant, relatively inexpensive and easy-to-produce metal.

“Spaceflight, medicine, wiring and more lightweight, more fuel-efficient automotive parts are some applications that come to mind,” Boldyrev says. “Of course, it’s very early to speculate about how this material could be used. There are many unknowns. For one thing, we don’t know anything about its strength.”

Still, he says, the breakthrough discovery marks a novel way of approaching material design.

“An amazing aspect of this research is the approach: using a known structure to design a new material,” Boldyrev says. “This approach paves the way for future discoveries.”

Journal of Physical Chemistry C – Supertetrahedral Aluminum – a New Allotropic Ultra-Light Crystalline Form of Aluminum

A new metastable ultra-light crystalline form of aluminum has been computationally designed using density functional calculations with imposing periodic boundary conditions. The geometric and electronic structures of the predicted new allotrope were calculated on the basis of a diamond lattice in which all carbon atoms are replaced by aluminum Al4 tetrahedra. The new form of crystalline aluminum has extremely low density 0.61 g/cm3 and would float in water. The new aluminum form is a semimetal and shows high plasticity.