The first silicon analogue of a carbonic ester, compound 2, and the novel cyclodisiloxane 4 have been synthesized by remarkably clean mono-and dioxygenation reactions of the stable siloxysilylene 1 with N2O (CO2) and O-2, respectively. Ester 2 represents a unique donor-supported SiO complex with an intriguing thermal stability up to 200 degrees C. The addition of MeOH at the SiO bond in 2 furnishes the corresponding adduct 3.