Five nickel (II) A - Zealites (16.6 -76.6% exchanged) were investigated using volu­metric, gravimetric, spectroscopic and magnetic susceptibility techniques. Upto 65% exchenged the fo~owing vacuum dehdtation sequence was determined:Ni+(H20)6 (Octahedral) 340K Ni2+(H20)3 (Ox)3  (quasi octahedral) 400K Ni2+(H20)2 (O2)3 (Trigonal bipyramid) 620K Ni2+ (O2)3 (Trigonal)(Where (Ox) represents the oxygen atom of the lattice of the zeolite).All the zeolites except 77% exchanged, showed the retension of the aluminositcate framework structures ~oth after preparation and upto 620K evacuation.