All-Benzenoid Systems: an Algebra of Invariants

The current invariants of all-benzenoids (h, n, m, nu na s - defined in the Introduction), in addition to the number of full and of empty hexagons (v and t), are studied. Their possible values are specified. Some of the relations between these invariants are summarized in a systematic way. The upper and lower bounds for all of them are accounted for as functions of any of these invariants

Molecular vibrations of complex with trigonal ligands

A normal coordinate analysis is performed for the compound (Pd INH3)4]2+ of symmetry C4h.Two general valence force fields which reproduce satisfactorily the observed frequencies are developed. These calculations for the whole complex (C4h) are compared with the point mass model approximation [Math], the validity of which is confirmed.Finally the refined force field for [Math] is used to calculate the frequencies of various isotopically substituted complexes (14N/15N, H/D) and the mean amplitudes of the mother molecule