  The effective pair potentials of liquid nickel have been derived by means of
the inverse self-consistent method from the experimental diffraction data. The
potentials provide highly accurate coincidence of experimental and simulated
structural properties. The statistical analysis of Voronoi polyhedral and
Delaunau simplices has shown that in the vicinity of the melting point in the
structure of liquid nickel there are relatively stable spatial polytetrahedral
formations with local 5-folder symmetry. With temperature rise such formations
evolve to isolate and compact ones with preserving of the local five-folder
symmetry.
