In a previous letter we presented the material dispersion in a ZrF4 based fluoride glass. The zero crossover wavelength λc was found to occur between 1.6 and 1.7 μm. Here, we analyse the refractive index measurements against wavelength data in order to obtain some physical parameters of this material on which λc is dependent: electronic energy gap E0, electronic oscillator strength ED, lattice oscillator strength E1 and structure factor B. Such values, which are not yet known for fluoride glasses, will be then compared with those corresponding to SiO2 glass. Evaluation of the Rayleigh scattering coefficient will also be made.