Vapor Species of the Barium-Oxygen System

Abstract

Mass-spectrometric and vacuum-thermobalance studies of barium oxide between 1365° and 1917°K yield for the equilibrium pressure of BaO gas, logPatm = − 22610 / T + 7.90. The enthalpy for the reaction BaO(a) = BaO(g) was calculated to be ΔH°298 = 110.9 ± 2.8 kcal / mole by the second-law method. The third-law date are consistent with this value if a 3Π state is assumed to be at or near (within a few hundred cm−1) the ground state of BaO(g). The heat of sublimation of the dimer Ba2O2(g) was found from the mass-spectrometer study to be about 142 kcal/mole and the heat of the reaction BaO(g) + Ba(g) = Ba2O(g) was found to be − 73 ± 15 kcal/mole at 1800°K. No reaction of barium oxide at 1800°K with O2(g) at pressures up to 10−3 atm was detected.

The standard molar enthalpies of formation of BaO(g) and SrO(g)

“…Their results for BaO(g) were confirmed by the measurements of Hilpert and Gerads, (25) who used different liners in their Knudsen cells, and by Farber and Srivastava. (24) Other measurements by Colin et al, (21) Newbury et al, (22) and Semenov et al (23) differ from the preceding measurements to some extent. Due to a lack of experimental details, it is very difficult to recalculate Colin's measurements accurately.…”

Thermodynamics and (p,T,x) phase diagram of (barium oxide + diyttrium trioxide)

“…method. (11) That confirms the validity of the adduced assumptions and equilibrium conditions of the effusion experiment in this work.…”

Chemical studies of stack fly ash from a coal-fired power plant

“…Barium. Barium oxide forms the volatile species Ba(OH>2 in steam at temperatures between 1155 and 1626 °C (34). Because the coal in our study contains 6.8% water and combustion temperatures at the plant range from 1500 to 1600 °C, the formation of volatile Ba(OH)2 is possible.…”