  Using projector augmented wave approach within the generalized gradient
approximation, we have studied the structural property and electronic structure
of ZrB12. The calculated lattice constants and bulk modulus are in good
agreement with the available experimental values. A detailed study of the
electronic structure and the charge-density redistribution reveals the features
of strong covalent B-B and weak covalent Zr-B bondings in ZrB12. The states at
the Fermi level mainly come from the $\sigma$-$p_{y}$ and $\pi$-$p_{z}$
orbitals of boron atoms, which are slightly hybridized with the
$t_{2g}$-$d_{xz}$ and $t_{2g}$-$d_{yz}$ orbitals of Zr atoms. As the increased
hydrostatic pressure on ZrB12, the total density of states at the Fermi level
decreases.
