Assertion: graphite's form | /r/HasProperty | heptagons of carbon atoms
Facets:
value: in place of flat hexagonal cells
type: LOCATION
Source sentences:
text: Fullerenes are a synthetic crystalline formation with a graphite-like structure, but in place of flat hexagonal cells only, some of the cells of which fullerenes are formed may be pentagons, nonplanar hexagons, or even heptagons of carbon atoms.