Experimental and computational investigations on the AlH3/AlF3 system

The possibility of changing the thermodynamic properties of AlH3, alane, by fluorine anion substitution has been investigated by experimental measurements, ab initio calculations and thermodynamic modelling. No solid solution phases are observed experimentally. In accordance to this the calculations give a positive free energy of mixing for all compositions, showing that a mixed phase is not thermodynamically favourable. Thus fluorine anion substitution does not seem feasible for the alane system.

Research highlights▶ Combined experimental screening study, ab initio calculations and thermodynamic modelling of the AlH3/AlF3 system. ▶ Calculations give a positive free energy of mixing for all compositions; a mixed phase is not thermodynamically favourable. ▶ No solid solution phases are observed experimentally. ▶ Fluorine anion substitution does not seem feasible for the alane system.