ENTHALPY OF FORMATION OF TRIPHENYLPHOSPHINE SULFIDE

The first measurements of the enthalpies of combustion, sublimation, a nd fusion of an organophosphorus sulfide, triphenylphosphine sulfide, are reported: Delta(c)H(m) degrees(C18H15PS, cr) = -(10752.58 +/- 2.90 ), Delta(sub)H(m) degrees(C18H15PS, 403 K) = (136.80 +/- 6.09), and De lta(fus)H(m) degrees(C18H15PS, T-m = 435.92 K) = (30.53 +/- 0.21) kJ . mol(-1). Correction of the phase change enthalpies to T = 298.15 K an d p degrees = 0.1 MPa results in the standard phase change enthalpy va lues of Delta(sub)H(m) degrees(298. 15 K) = (142.8 +/- 6.8) and Delta( fus)H(m) degrees (298.15 K) = (19.28 +/- 0.21) kJ . mol(-1). According ly, the enthalpies of formation of solid, liquid, and gaseous tripheny lphosphine sulfide are derived: Delta(f)H(m) degrees(C18H15PS, cr) = ( 63.20 +/- 2.56), Delta(f)H(m) degrees(C18H15PS, l) = (82.48 +/- 2.57), and Delta(f)H(m) degrees(C18H15PS, g) = (206.0 +/- 7.3) kJ . mol(-1). From these ancillary data, the P=S double-bond enthalpy is 394 kJ . m ol(-1) and in good agreement with earlier reaction calorimetry results . These phosphorus sulfide values are compared with those for the arse nic sulfides. Plausibility arguments are given for our results.