In contrast, graphite, in addition to being the most stable form of bulk carbon, has a flat layered structure that would require largescale reorganization to fully onionize, and these factors presumably account for the observation that the transition to inertness requires long oxidation times with large mass losses. O2 is known to be unreactive with perfect basal plane sites, but is reactive with defects in exposed basal planes, and with the "prismatic" faces of graphite crystallites, i.e., faces that expose the edges of the stacked basal planes. Lateral etching at basal plane defects is substantially faster than etching into the underlying basal plane, and thus tends to form 2D "etch pits" that expand as O2 etches under-coordinated atoms around the internal perimeter, and as the pit expands, the etching rate increases. Thus, etching rates may fluctuate, increasing as pits expand, then decreasing as the basal plane is consumed, exposing the underlying plane, and Because the prismatic faces of graphite are reactive with O2 in our TNP range, to become inert to O2 these faces have to reconstruct to eliminate under-coordinated reactive sites. Graphite prismatic edges are known to form "closed-edge" structures, where a graphene sheet can fold over and connect to the edge of a neighboring sheet, forming a bilayer connected by a highly curved, but closed edge (also known as looped or arched edge structures). Furthermore, concentric closed/arched edge surfaces can connect together a series of sheets, effectively converting that portion of the prismatic face to a fully coordinated structure. Thus, a possible intermediate step toward encasing graphitic NPs in a fully-coordinated shell might be formation of closed/arched structures.