Thermodynamic properties of the alloys { xBa + (1 − x)P}

Abstract

A Knudsen-effusion method combined with mass-spectral analysis of the gaseous phase has been employed to investigate thermodynamic properties of {xBa + (1 − x)P} alloys (0.5 ⩽ x ⩽ 0.6) over the temperature range 1178 K to 1483 K. Stoichiometric compounds BaP and Ba3P2 as well as alloys with compositions belonging to the two-phase equilibrium region (BaP + Ba3P2) were studied. The standard molar Gibbs energies of formation of BaP and Ba3P2 from gaseous phosphorus and liquid barium in the temperature range investigated have been expressed by the equations: Δ f G m o ( BaP ) / ( J ⋅ mol − 1 ) = − ( 306804 ± 1180 ) + ( 79.42 ± 0.89 ) ⋅ ( T / K ) , and Δ f G m o ( Ba 3 P 2 ) / ( J ⋅ mol − 1 ) = − ( 736708 ± 3014 ) + ( 171.43 ± 2.21 ) ⋅ ( T / K ) .