atoms, composing the so-called [*5-8-5*]{} defect of an octagon and a pair of pentagons as it is shown in Fig. \[Vac1\]b. We calculated the formation energy of DV, presented in Table \[table2\], which is equal to $\epsilon^f_{DV}\approx 5.76~eV$. [*Ab-initio*]{} calculations of the DV formation energy by other authors [@eteh03; @klfn06] indicate $\sim 8eV$. The energy $\epsilon^f_ {DV}$ is smaller than that for a monovacancy in a graphene, confirming that DV formation in the graphene is rather favorable. Divacancies create a quasi-localized state with energies close to the Fermi energy $E_F$; at the same time they remove the band crossing, destroying the gapless states at [*K*]{}-points of the Brillouin zone (see, Fig.\[Vac1\]b). All the dangling bonds corresponding to the same sublattice rebind again, and therefore the DV does not generate a magnetization (see, Table \[table2\]).

The [*5-8-5*]{} divacancy, consisting of two pentagons and one octagon, has another modification [*555-777*]{}, which is structured by three pentagons and three heptagons. The [*555-777*]{} defect is formed by removing two carbon atom and by additional creation of a Stone-Wales (SW) defect [@sw86], e.g. by additional rotation of one [*C-C*]{} bond in the octagon.

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Although [*555-777*]{} DV, with formation energy smaller then 