Hydrofluoride synthesis performance

If the quality of the product is not so critical or if further purification steps are planned, hydrofluoride synthesis can be performed using a regular black steel container. 

Hydrofluoride decomposition, 263-266 Hydrofluoride synthesis fluorotantalates, 41-47 general information, 38-41 oxyfluoroniobates, 49-54 performance, 46-47, 57 Hydrolysis, 7, 16,317-318 Hydrolysis of... 

The synthesis of tantalum and niobium fluoride compounds is, above all, related to the fluorination of metals or oxides. Table 3 presents a thermodynamic analysis of fluorination processes at ambient temperature as performed by Rakov [51, 52]. It is obvious that the fluorination of both metals and oxides of niobium and tantalum can take place even at low temperatures, whereas fluorination using ammonium fluoride and ammonium hydrofluoride can be performed only at higher temperatures. 

The hydrofluoride method can be used successfully both for the preparation of complex fluoride compounds and of complex oxides. The main advantage is that the synthesis is performed at relatively lower temperatures. In addition, the complex oxide material is formed through its respective fluoride compound and the product obtained is therefore more consistent. For instance, Co4Nb209 can be prepared using the hydrofluoride method at 900-1100°C, whereas the regular synthesis, based on the interaction of simple oxides, requires extended treatment at about 1400°C. 

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