THERMODYNAMIC PROPERTIES OF THE AQUEOUS BA2+ ION AND THE KEY COMPOUNDS OF BARIUM

Recommended thermochemical property values, Delta(i)H degrees, Delta(i)G degrees and S degrees for the aqueous ion of barium, Ba2+, are given at 298.15 K in SI units. The values are: Delta(f)H degrees = -534.64 +/- 1.80 kJ . mol(-1), Delta(f)G degrees = -557.60 +/- 1.81 kJ . mol(-1) and S degrees = 8.80 +/- 0.50 J . K-1 mol(-1). They are consistent with the CODATA Key Values for Thermodynamics. The evaluation involves the analysis of the enthalpy changes, Gibbs energy changes, and the entropy measurements for all key substances in the key network. A consistent set of thermochemical property values is given for BaO(cr), BaH2(cr), BaCl2(cr), BaCl2 . 2H(2)O(cr), Ba(NO3)(2)(cr), and BaCO3(cr,witherite), as well as reconstituted recommended process values with uncertainties for reactions involving these substances. (C) 1995 American Institute of Physics and American Chemical Society.