It has been shown that in the interaction of carbon dioxide with the bis(trimethylsilyl)acetylene complex of permethyltitanocene Cp * 2 Ti(Me 3 SiC 2 SiMe 3 ), full displacement of bis(trimethylsilyl)acetylene from the titanium coordination sphere takes place and carbon dioxide undergoes disproportionation to form Cp * 2 Ti(CO) 2 and the binuclear carbonate complex of permethyltitanocene (Cp * 2 Ti) 2 CO 3 . The structure of (Cp * 2 Ti) 2 CO 3 has been established by X-ray diffraction study. Structural data on the related chlorine-containing carbonate complex Cp * 2 Ti(Cl)CO 3 TiCp * 2 are also reported.