Sublimation study of BiBr3

Abstract

Steady-state sublimation vapour pressures of anhydrous bismuth tribromide have been measured by the continuous gravimetric Knudsen-effusion method from 369.3 to 478.8 K. Additional effusion measurements have also been made from 435.4 to 478.6 K by the torsion—effusion method. Based on a correlation of Δsub H 298 0 and Δsub S 298 0 , a recommended p(T) equation has been obtained for BiBr3(s) $$\alpha - {\rm B}i{\rm B}r_3 :log{\text{ }}p = - C\alpha /T - 12.294log{\text{ }}T + 5.79112 \times 10^{ - 3} {\text{ }}T + 47.173$$ with Cα=(Δ subH 298 0 +20.6168)/1.9146×10-2 $$\beta - {\rm B}i{\rm B}r_3 :log{\text{ }}p = - C\beta /T - 23.251log{\text{ }}T + 1.0492 \times 10^{ - 2} {\text{ }}T + 77.116$$ with Cβ=(Δ subH 298 0 +46.2642)/1.9146×10-2 where p is in Pa, T in Kelvin, Δ sub H 298 0 in kJ mol−1. Condensation coefficients and their temperature dependence have been derived from the effusion measurements.