  Electronic structure and cohesive properties of metastable hexagonal AgB_{2}
and silver-deficient borides Ag_{0.875}B_{2} and Ag_{0.750}B_{2} were
investigated by means of the projected augmented wave method in the framework
of the density functional theory (VASP package). We found that the density of
states at the Fermi level for nonstoichiometric diborides is almost constant
within a range of vacancy content up to 25%. The formation energy of metal
vacancies in silver diboride is the least among all 4d metal diborides, i.e.
for AgB_{2} is possible to expect the wide homogeneity region.
