Crystallographic analysis of an intramolecularly stabilised organosilver tetramer, [Ag(C6H4NMe2-2)](4), and the first structurally characterised silver siloxide, {[Ag(PPh3)](2)-(mu(4)-OMe2SiOSiMe2O)}(2)

Recrystallisation of [Ag(C6H4CH2NMe2-2)](4) 1 in the presence of PPh3 has led to the isolation of a silver siloxide, {[Ag(PPh3)](2)(mu(4)-OMe2SiOSiMe2O)}(2) 2, from interaction with the silicone grease used to assemble the glassware. Both compounds have been characterised crystallographically, and 2 represents the first structurally characterised silver siloxide. The organometallic is a planar tetramer containing both four-and six-co-ordinate silver. The disiloxide adopts a dimeric 'step' structure incorporating trigonal PO2Ag and tetrahedral PO3Ag centres.