MOLECULAR MODELING OF DIMETAL SYSTEMS - PART 3 - DICHROMIUM BONDS

Compounds containing dichromium bonds have been modeled in comparison with related dimolybdenum systems by molecular mechanics, in order to establish a sampling curve that reflects the functional relationship b etween characteristic bond length, r(o), harmonic force constant, k(r) , and bond order, N, for all Cr-n-Cr. Intersection of the sampling cur ve with any molecular-mechanics solution curve {k(r), r(o)}, for dichr omium compounds identifies an effective bond order for the Cr-Cr bond. By this approach the known flexibility of dichromium bonds of constan t formal bond order was analyzed. and it was shown that the effective bond order is not a function of electron count only but also relates s ensitively to both axial and equatorial ligation.