Low energy three-dimensional hydrocarbon crystal from cold compression of benzene.

We demonstrate an interesting phase transition from cold compressed benzene to a fully saturated three-dimensional hydrocarbon crystal, Hex-CH. The very low transition point pressure, remarkable energetic stability and positive dynamical stability indicate that Hex-CH is a promising three-dimensional hydrocarbon crystal. As a transparent insulator and potential hard hydrocarbon material, Hex-CH is expected to be of general interest in organic chemistry, condensed matter physics and material science.