Mixed metal acetate hydrazines

The procedure for synthesizing mixed metal acetate hydrazines is to add an excess of alcoholic hydrazine hydrate to a solution containing a mixture of the corresponding metal acetates, in the molar ratio of 1 2 [12]. The precipitated complexes are filtered, washed with ethanol and then diethyl ether, and stored in a vacuum desiccator over P2O5. This method has been used to prepare solid solutions of mixed metal acetate hydrazines of the type Mv3Co2/j(CH3COO)2(N2H4)2 (M = Ni or Zn ), which are precursors to nickel and zinc cobaltites. 

Reaction of Metal Oxalate Hydrates with Hydrazine Hydrate 

Freshly prepared metal oxalate hydrates are treated with stoichiometric quantities of hydrazine hydrate. As the mixture is thoroughly stirred the reaction takes place instantaneously with the evolution of heat. In some cases, a change of color in the original salt is observed due to complex formation (Table 3.10). 

Reaction of Aqueous Solutions of Metal Salts with Alcoholic Hydrazine Hydrate 

The conventional procedure for preparing metal oxalate hydrazine complexes is to treat an aqueous solution of the metal salt with an alcoholic solution of hydrazine hydrate  

---

These precursors decompose exothermically in the temperature range 165-345 °C to yield the corresponding cobaltites, as depicted by the thermal analyses (Figure 3.7) [13]. Table 3.9 gives the thermal data of the mixed metal acetate hydrazines. 

As the structure of metal acetate hydrazine complexes appears to be isomorphous, the formation of mixed metal hydrazines takes place easily. This is further confirmed by the identical infrared spectra of Nii/3Co2/3(CH3COO)2(N2H4)2 with the nickel and cobalt acetate hydrazine complexes (Figure 3.6). 

The formation of cobaltites (MC02O4) from the combustion of mixed metal oxalate/acetate hydrazine complexes and solid solutions of hydra-zinium metal hydrazine carboxylate hydrates have been discussed in Chapters 3 and 4, respectively (Sections 3.2.4.1, 3.2.6 and 4.6). The final product, confirmed by X-ray diffraction pattern, shows the characteristics of cobaltite spinels. Similar to cobaltites, mixed metal oxalate/acetate hydrazines complexes undergo single-step decomposition to form... 

---