Equilibrium dissociation pressures of NbBr5 over NbBr4

Equilibrium pressures of the dissociation of niobium tetrabromide into pentabromide and tribromide:[Formula: see text]where x lies in the range 2.67 to 3.03 have been measured over the temperature range 275–365 °C. The dissociation pressures were determined by measuring the dew points of NbBr 5 vapor in a closed system containing NbBr 4 and NbBr x The equilibrium decomposition pressure of NbBr 4 at a given temperature was found to be much lower than that of NbCl 4 , thereby indicating that NbBr 4 is significantly more stable than NbCl 4 .