A thermochemical study involving adducts MX2*P(C6H5)3O (M = Zn, Cd, Hg; X = Br, I)

Article abstract of DOI:10.1016/0021-9614(86)90103-5

The standard molar enthalpy Δ_rH⁰_m of the reaction: MX2(s) + 2P(C6H5)3O(s) = MX2*2P(C6H5)3O(s), where M = Zn, Cd, Hg and X = Br, I (except HgI2) was obtained through the determination of the enthalpy of dissolution of the metal halides, ligand, and adducts in calorimetric solvent, giving the values: -(69.92 +/- 1.10); -(63.02 +/- 0.39); -(16.02 +/- 0.56); -(30.55 +/- 0.87); and -(16.48 +/- 1.14) kJ/mol, for the sequence of halides: ZnBr2, ZnI2, CdBr2, CdI2, and HgBr2.The standard molar enthalpies of formation were also determined: -(622.2 +/- 6.8), -(495.0 +/- 6.3), -(556.2 +/- 6.5), -(457.8 +/- 7.1), and -(411.1 +/- 6.4) kJ/mol, for the above sequence as well as the standard enthalpies of reaction: Δ_dH⁰_m for MX2*2P(C6H5)3O(s) = MX2(s) + 2P(C6H5)3O(g); and Δ_lattH⁰_m for MX2*2P(C6H5)3O(s) = MX2(g) + 2P(C6H5)3O(g).The mean enthalpy of dissociation of the metal-oxygen bond, (M-O), was also estimated and compared with other results.