With the synthesis of new perfluoroalkyltellurocarbonyls, their precursors and cyclic dimers additional valuable information about these classes of compounds has become available. They were prepared via pyrolysis of Me3SnTeCF(CF3)2 and the novel compounds Me3SnTeR (R = n-C3F7, n-C4F9). The monomer (CF3)2CTe could not be detected as it dimerises quantitatively to the corresponding 1,3-ditelluretane. It was possible to isolate R(F)CTe (R = C2F5, n-C3F7) at −196 °C, but slightly above this temperature, these compounds cyclise to mixtures of cis/trans 1,3-ditelluretanes. The tellurocarbonyls undergo [4 + 2]-cycloaddition reactions with 2,3- dimethylbutadiene providing the corresponding tellurins. The reaction between RTeTeR and mercury yielded Hg(TeR)2 which have been converted with iodine in CH2Cl2 solution to RTeI. With AgCN the in situ prepared iodides form RTeCN (R = CF(CF3)2, n-C3F7, n-C4F9) in good yields. A new type of compound has been synthesized by chlorination of tetrafluoro-1,3-ditelluretane: 1,3-dichloro-2,2,4,4-tetrafluoro-1λ4,3λ4-ditellurabicyclo[1.1.0]butane. It is only stable below −20 °C and rearranges almost quantitatively at room temperature to ClF2CTeTeCF2Cl.