Professor Chen’s recent work on designing two- dimensional materials containing planar pentacoordinate carbon was published in Nature Communications.

There is tremendous research into new materials with interesting topological properties. Recently, by means of density functional theory computations, Professor Zhongfang Chen and his collaborators designed a two-dimensional (2D) material, namely Be5C2 monolayer,  in which each carbon atom is bonded to five beryllium atoms forming a quasi-planar pentacoordinate carbon moiety. According to their computations, the Be5C2 monolayer has good stability and is the lowest-energy structure in the 2D space. The novel structure endows Be2C monolayer many fascinating properties. It is a gapless semiconductor with a Dirac-like point at the Fermi level, which is quite similar to that of graphene. More interestingly, Be2C monolayer has a rather peculiar negative Poisson’s ratio, which means that it can be compressed or stretched in both two directions at the same time. These properties make Be2C monolayer a rather promising candidate for future electronic and mechanic devices.

Geometric and electronic structures of Be5C2 monolayer. Be9C24- molecule. Electronic properties of Be5C2 monolayer.

For more details, please refer to

Semimetallic Be5C2 Monolayer Global Minimum with Quasi-Planar Pentacoordinate Carbons and Negative Possion’s Ratio
Yu Wang, Feng Li, Yafei Li,* Zhongfang Chen*
Nature Communications, 2016, 7, 11488.