| Abstract: | The geminal frustrated Lewis pair (F5C2)3SnCH2P(tBu)2 ( 1 ) reacted with N‐sulfinylaniline PhNSO to afford the first sulfur monoxide adduct of a main group metal, (F5C2)3SnCH2P(tBu)2?SO ( 2 ), which contains a SnCPSO ring. The second product is a phenylnitrene adduct of 1 . The surprising stability of 2 was compared with the stabilities of the so far inaccessible O2 and S2 adducts of 1 . Attempts to prepare these from 1 and the elemental chalcogens (O2, S8, Se∞, Te∞) led to four‐membered SnCPE ring systems. Quantum‐chemical investigations of 2 demonstrate the bond polarity of the SO unit to stabilize 2 . |
