Preparation of reactive nickel oxide by the controlled thermolysis of hexahydrated nickel nitrate

Sample Controlled Thermal Analysis is used to highlight the role of the experimental pressure on the thermolysis of hexahydrated nickel nitrate to nickel oxide. At 5 X 10(-2) mbar, dehydration occurs before denitration begins. Formation of an amorphous material occurs, corresponding to the composition of the monohydrate. At 5 mbar, a basic salt is formed. Both these thermal decompositions occur in the solid state whereas at 100 mbar melting occurs, The nature of the nickel oxide formed depends strongly on the experimental pressure. Increasing this pressure increases the temperature of nickel oxide formation. At 5 X 10(-2) mbar an oxide of 80 m(2)g(-1) is obtained whereas at 5 mbar and 100 mbar no significant surface area accessible to nitrogen is observed.