The adsorption and thermal behavior of (eta(6)-benzene)tricarbonylchromium(O), (eta(6)-C6H6)Cr(CO)(3), inside zeolite Y have been investigated under different conditions by the FT-Raman technique in coni I unction with FT-IR spectroscopy. The thermal decomposition of (eta(6)-C6H6)Cr(CO)(3) in zeolite Y seems strongly dependent on the experimental conditions employed: heating (eta(6)-C6H6)Cr(CO)(3) adsorbed inside zeolite Y in a Schlenk tube under nitrogen flow results in the formation of benzene and Cr metal, whereas heating the same complex in a closed vessel yields a different metal carbonyl species, Cr(CO)(6). The thermal behavior observed in the present study is different from that reported previously in the literature.