The relationship between bond order (N), harmonic force constant (k(r)) and
characteristic bond length free of strain (r(0)) for dirhenium bonds has b
een studied by molecular-mechanics simulation of suitable structures well c
haracterized by X-ray diffraction. It follows the same trend, N = ak(r) = a
br(0)(-5), found before for dimolybdenum and dichromium bonds. (C) 2000 Els
evier Science S.A. All rights reserved.