Preparation of sodium dimolybdate by the pyrolysis of sodium oxomolybdenum (VI) oxalate

Thermal studies on various oxalato complexes have been of immense interest as they yield finely divided, highly reactive oxides which are usually obtained at a much lower temperature than that required in the conventional method of preparation, i.e., heating a mixture of two or more constituents 1]. A survey of the literature reveals that the compounds having the general formula A₂Mo₂O₅(C₂O₄)₂(H₂O)₂], where A = K⁺, NH⁺₄2] and A = Cs⁺ 3], have been prepared and their thermal decomposition is studied, but no such information is available regarding the preparation and characterisation of Na₂Mo₂O₅(C₂O₄)₂(H₂O)₂] (SMO), which forms the subject of study of this paper. Sodium dimolybdate (Na₂Mo₂O₇), the decomposition product of SMO, is obtained at 280°C, a temperature much lower than that required in the conventional method of preparation of heating a mixture of Na₂MoO₄ and MoO₃ 4].