BONDING OF AG-2+ IN KCL LATTICE

The bonding properties of Ag**2** plus in KCl have been derived from a reliable analysis of the EPR and optical data which yield that the electronic charge for the antibonding 3b//1//g(x**2-y**2) and 2e//g(xz, yz)//61//Ag**2**levels lies mainly on ligands. This strong covalency, higher than that for CuBr//4**2** minus , is consistent with the value 2. 8 derived for the optical electronegativity of Ag+ZZ plus and with the fact that the left bracket g right bracket tensor is dominated by the second-order contribution due to charge transfer excitations. The corresponding contribution to g PERPEND minus g//0 coming from crystal field (CF) states if found to be negative which cannot be understood in a pure CF description. A value equal to 326 kG is obtained for the core polarization contribution to the hyperfine field.