Mixed Metal Sulfite Hydrazines

A solid compound separates out initially, which is washed with 50% alcohol until free from sulfate it is then washed with diethyl ether and dried in a vacuum desiccator over P2O5. Chemical analyses of the mixed metal sulfite hydrazine hydrates confirms a stoichiometry of MFe2(S03)3 6N2H4 2H20. The reaction can be written as follows  

Since the synthesis of these compounds is carried out in the presence of a strong reducing agent like hydrazine, iron remains in the ferrous state. Analytical data and qualitative tests support this observation. However, on long exposure to the atmosphere, Fe(II) in the compounds is oxidized to Fe(III). 

The prepared mixed metal hydrazine hydrates are light in color and insoluble in water. From the chemical analysis it is evident that all mixed metal complexes, including magnesium, are present as sulfite [21]. However, when magnesium alone is used without FeS04, a bisulfate hydrazine is obtained under the same preparative conditions. 

The combustion of mixed metal sulfite hydrazine complexes in the presence of air (—300 °C) gives homogenous ferrites (Table 3.18). This is confirmed by the observed weight loss and powder XRD. 

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