It melts at 3727 C. The stable form of carbon at room temperature is Graphite which has a hexagonal crystal structure. (Top diagram) Diamond is metastable at room temperature and has a diamond cubic ...
These phases include disordered graphene network (DGN), high-density amorphous carbon (HDAC), amorphous diaphite (a-DG), amorphous diamond ... the development of a phase diagram in the sp 3 ...