N NQR and the Molecular Charge Topology in Coordinated Ammonia *

1 4 N N Q R spectra of [Co(NH 3 ) 6 ] • 3C1, [ C o ( N H 3 ) 5 C 0 3 ] • N 0 3 , [ Zn (NH 3 ) 4 ] • 2C1, [Zn (NH 3 ) 4 ] • (BF 4 ) 2 , and [Ag (NH 3 ) 4 ] • N 0 3 were obtained at 77 K . The results, analyzed by means of the topology of the charge distr ibut ion obtained from ab-initio M O calculations of free and of a model of coordinated N H 3 , showed that bonding to the metalion 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.