Sonochemical Fabrication of Nano-Metallic Oxides

1 Sonochemical Synthesis of Transition Metal Oxides from the Corresponding Carbonyls 

The characterization of an amorphous material is difficult because it lacks characteristic XRD diffractions, so that Auger or Mossbauer spectroscopies are preferred, along with other conventional analytical assays such as spot test and iodo-metric titration [71]. The Fe203 nanoparticles are converted to crystalline Fe304 nanoparticles when heated to 420 °C under vacuum or when heated to the same temperature under a nitrogen atmosphere. The magnetization of pure amorphous Fe203 at room temperature is very low ( 1.5 emu g ) and it crystallizes at 268 °C. 

The sonochemical oxidation of molybdenum carbonyl would not occur in the bubble, due to its low vapor pressure. Therefore, the sonochemical reaction of 

Mo(CO)6 appears to take place in the interfacial region Thus, the water molecule formed in the bubble may diffuse into the interfacial region or the water molecules that are available from the atmospheric air, precursor, and solvent, and stabilize the unusual pentavalent molybdenum oxide  

2Mo(CO)g + I7/2O2 M02O5 + I2CO2 (Sonolysis) M02O5 T 2H2O — Mo205 2H20 

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