HYLIFE-II reactor uses molten salt Flibe as the liquid blanket materia
l. The property of its gaseous state was poorly known for gas dynamics
calculations and other design problems. This study presents two fitte
d equations of state of the Flibe gas to meet the needs. The fitted ra
nge covers both dissociation and ionization regions. The methods used
for fitting allow good agreement between the calculated data and fitte
d equations.