Standard molar enthalpy of formation of 4-iodobenzoic acid by static and rotating-bomb calorimetry

The standard (p(o) = 0.1 MPa) molar enthalpy of combustion of 4-iodobenzoic acid, at T = 298.15 K, was measured by static-bomb and rotating-bomb calor imetry, from which the standard molar enthalpy of formation, in the crystal line state, was derived. [GRAPHICS] The values obtained confirm that 4-iodobenzoic acid is a satisfactory test substance for combustion of organo-iodine compounds. Using a literature val ue for its standard molar enthalpy of sublimation, the standard molar entha lpy of formation, in the gaseous state, was also derived and compared with an estimate by means of structural contributions. (C) 1999 Academic Press.