The reactions of [W (⋮ CR)(CO) 2L](R= C6H3Me2-2, 6; L= η-C5H5, HB (pz) 3; pz= pyrazol-1- yl) with thionyl chloride depend on the nature of “L”: For L= η-C5H5, the metallacyclic carbene complex [W (κ2 CRSCRS) Cl3 (η-C5H5)] is obtained, while for L= HB (pz) 3, metal