The electronic structure and the chemical bonding mechanism of silver oxide
(Ag2O) are studied on the basis of band-structure calculations, using the
full-potential linearized augmented-plane-wave (FLAPW) method. Our calculat
ions indicate that silver oxide is a metal (or a semi-metal). Total and par
tial densities of states and electron densities were calculated and are uti
lized to give an interpretation of the chemical bonding. The admixture of t
he Ag 5s states with the Ag 4d-O 2p bands proved to be essential for the co
valent bonding effect, since pure 4d-2p bands, with bonding and antibonding
states fully occupied, do not lead to a covalent energy gain. It is found
that there are significant deviations from a simple ionic picture due to th
e depletion of the valence band of the Ag 4d electrons, leading to non-sphe
rical charge density around the silver.