Abstract 14 N NQR spectra of [Co(NH 3 ) 6 ] • 3Cl, [Co(NH 3 ) 5 CO 3 ] • NO 3 , [Zn(NH 3 ) 4 ] • 2Cl, [Zn(NH 3 ) 4 ] •(BF 4 ) 2 , and [Ag(NH 3 ) 4 ] • NO 3 were obtained at 77 K. The results, analyzed by means of the topology of the charge distribution obtained from ab-initio MO calculations of free and of a model of coordinated NH 3 , showed that bonding to the metal-ion produces a strong decrease (Co ≫ Zn ≈Ag) in the N nonbonded density ("lone pair") and an increase in the bonded maxima found in the N - H bond direction of the N valence shell.
