The atoms of the 5th element of the periodic table often find themselves in the company of each other, forming allotropes with a rich variety of structural motifs, each carrying a unique set of chemical and physical properties. Despite the long catalog, most boron allotropes do not simultaneously possess high electrical conductivity and plasticity, but a recent study has expanded the portfolio.

Scientists have now designed a new allotrope called Imma-B60 by washing out the sodium from the sodium boride compound Na4B60. Their findings are published in Nature Chemistry.

Unlike the dense, tightly packed atomic arrangements found in standard forms of elemental boron, Imma-B60 forms a porous open framework built from 12-atom boron cages connected by 3-atom triangular boron units. This unique structure shifts internally under stress, allowing the allotrope to be flexible and deform by 23% without shattering. Imma-B60 also conducts electricity 10 million times better than the common form of boron, thanks to its very narrow bandgap of under 0.2 eV.