Europium tribromide has been found to vaporize incongruently according to the reaction:2EuBr3(s)=2EuBr2(s)+Br2(g).Static equilibrium vapor pressures have been measured by a spectrophotometric procedure in the temperature range 502 to 623 K. Equilibrium pressures were not attained in Knudsen effusion experiments. For the vaporization reaction, ΔHo(563 K)/kcalth mol-1 = (22.85 ± 0.18) and ΔSo(563 K)/calth K-1 mol-1 = (34.26 ± 0.32). Heat capacities have been estimated for the condensed bromides, and second- and third-law results are given. For the tribromide, ΔHof(EuBr3, s, 298.15 K)/kcalth mol-1 = -(186.1 ± 3.0), ΔGof(EuBr3, s, 298.15 K)/kcalth mol-1 = -(179.3 ± 3.0) and So(EuBr3, s, 298.15 K)/calth K-1 mol-1 = (50.7 ± 3.0). The preparative chemistry and phase equilibria of the europium + bromine system and the thermochemical data are discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33930/1/0000197.pd
