  The stability of graphene multivacancy systems is studied using Density
Functional Theory (DFT) calculations. This work describes the evolution of the
energy of formation per carbon atom for zigzag and armchair complementary
figures -i.e. the figure formed by the carbon atoms extracted from graphene to
form the vacancy-. Multivacancy systems formed when armchair complementary
figures are removed are more stable for higher orders (>5) in comparison with
the zigzag ones. The case of the construction of a 6-order vacancy from a
5-order one (branch-like) is discussed with the dependence on the place where
the extra carbon atom is removed from graphene. The stability of multivacancy
systems could be explained through the relative positions of the pentagonal
rings present in the resulting defected graphene structure, as the more
relevant factor. Other secondary factors that affect the stability of a
graphene multivacancy system are the dangling bonds magnetic arrangements and
their steric hindrance.
