by two by-products, a six-membered Si(SiO)2NH-ring (10) and a 1,3-diamino-1,3-disiloxane (11). The treatment of 6 with n-C4H9Li followed by LiF-elimination results in an eight-membered (SiOSiN)2-ring (13), the analogous reaction of 7 and 8 leads to the formation of four-membered (SiOSiN)-rings (14, 15). The results of the crystalstructure determinations of 2, 3, 9 the lithium salt of 8 (12) and quantum