Niobium thermodynamic propertie

The pentahalides of niobium and tantalum are predominantly covalent. Their volatility decreases from the fluorides to the iodides. Nb and Ta belong to the few elements which form stable pentaiodides. Selected physical and thermodynamic properties for the halides are listed in Table 2. All are sensitive to moist air, water or hydroxylic solvents. 

Veleckis, E. and Edwards, R.K., Thermodynamic properties in the systems vanadium-hydrogen, niobium-hydrogen, and tantalum-hydrogen. Journal of Physical... 

Experimental investigations of the thermodynamic properties Cr-Fe-Nb alloys have not been reported. Thermodynamic data for liquid, ferrite and austenite of some iron-based systems were optimized by [1998Mie] in order to give a more accurate representation of phase equilibria between these phases in multieomponent steels. But for the Cr-Fe-Nb system, the auflior has noted fliat a eareM examination of the system is necessary in order to get a reliable prediction of die partitioning tendency of niobium. 

Podarevskaya, O.V., 1992, Thermodynamic properties of scandium, titanium and niobium, Ph.D. Chemistry thesis (Institute of Material Problems, Kiev) pp. 1-17. 

Gerasimov et have provided a reference book on the thermodynamic properties of tungsten, molybdenum, titanium, zirconium, niobium, and tantalum, and their more important compounds, viz. oxides, sulphides, halides, carbides, nitrides, silicates, borides, and hydrides. 

Nevertheless, the system, composed of chain fragments of oxyfluoroniobate complexes, is thermodynamically less stable. Dipole properties of fragments of a certain length are re-orientated so as to be linked into typical infinite chains. There is no doubt that the fragment re-orientation and linking process initiates the partial reduction of niobium to Nb4+ and the oxidation of fluoride to elementary fluorine. The process scheme can be presented as follows ... 

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