  In order to explain room-temperature ferromagnetism of graphite-like
materials, this paper offers a new magnetic counting rule of radical carbon
zigzag edge nano graphene. Multiple spin state analysis based on a density
function theory shows that the highest spin state is most stable. Energy
difference with next spin state overcomes kT=2000K suggesting a
room-temperature ferromagnetism. Local spin density at a radical carbon shows
twice a large up-spin cloud which comes from two orbital with tetrahedral
configuration occupied by up-up spins. This leads a new magnetic counting rule
to give a localized spin Sz=+2/2 to one radical carbon site, whereas Sz= -1/2
to the nearest carbon site. Applied to five model molecules, we could confirm
this magnetic counting rule. In addition, we enhanced such concept to oxygen
substituted zigzag edge occupied by four electrons.
