Send to

Choose Destination
See comment in PubMed Commons below
Phys Rev Lett. 2009 May 1;102(17):175506. Epub 2009 Apr 29.

Superhard monoclinic polymorph of carbon.

Author information

State Key Lab of Superhard Materials, Jilin University, Changchun 130012, China.


We report a novel phase of carbon possessing a monoclinic C2/m structure (8 atoms/cell) identified using an ab initio evolutionary structural search. This polymorph, which we call M-carbon, is related to the (2x1) reconstruction of the (111) surface of diamond and can also be viewed as a distorted (through sliding and buckling of the sheets) form of graphite. It is stable over cold-compressed graphite above 13.4 GPa. The simulated x-ray diffraction pattern and near K-edge spectroscopy are in satisfactory agreement with the experimental data [W. L. Mao, Science 302, 425 (2003)10.1126/science.1089713] on overcompressed graphite. The hardness and bulk modulus of this new carbon polymorph are calculated to be 83.1 and 431.2 GPa, respectively, which are comparable to those of diamond.

PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for American Physical Society
    Loading ...
    Support Center