Hydrofluoride synthesis performance and capability

If applied, it is necessary to double the amount of ammonium fluoride compared to ammonium hydrofluoride, and to take into account the increased amount of gaseous NH3 released. 

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. 

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, Co4Nb2C 9 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. 

Compound Initial composition and temperature, °C Gaseous components 

CRYSTAL CHEMISTRY OF TANTALUM AND NIOBIUM FLUORIDE COMPOUNDS 

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