  Three different CrNi2 complexes were synthesized. They differ from each other
by the nature of the terminal ligand and of the counter anion :
[Cr(CN)4[CN-Ni(tetren)]2]Cl, that crystallizes in two different
crystallographic systems and [Cr(CN)4[CN-Ni(dienpy2)]2](ClO4). The ground state
spin value is 7/2 for the three systems (ferromagnetic interaction between
chromium(III) and nickel(II) ions). The magnetisation of the three CrNi2
complexes was measured using an array of micro-SQUIDs in a temperature range
between 0.04 K and 7 K, under a magnetic field up to 1 T. The three samples
present a three dimensional magnetic ordering. The correlation between the
structure and the intermolecular coupling is analysed in terms of steric
hindrances of the terminal ligand, orientation of the molecules in the unit
cell (canted structure) and crystal symmetry.
