Enthalpy of formation of pentacarbonyl(triphenylphosphine) tungsten and of pentacarbonyl(methoxy(phenyl)methylene)tungsten

Abstract Microcalorimetric studies on the sublimation, thermal decomposition and bromination of W(CO) 6 , and of the complexes [W(CO) 5 (PPh 3 )] and [W(CO) 5 {C(OMe)Ph}] have provided standard enthalpies of formation (in kJ mol −1 ) of the crystalline and vapour states respectively as follows: W(CO) 6 −(960 ± 3), −(887 ± 4); [W(CO) 5 (PPh 3 )]−(729 ± 7), −(585 ± 8); [W(CO) 5 {C(OMe)Ph}] −(724 ± 11), −(620 ± 12). The bond enthalpy contribution of the non-carbonyl ligand in these complexes is calculated; the results are consistent with some degree of double-bond character in the Wligand bond.