and one equivalent of the corresponding silyl azide (Schemes 1 and 7). Similar reactivity has been reported for the reaction of Dipp-imide complex K2[VII]2 with N2O, which also generates K2[VIIIb]2 together with DippN3. By contrast, when a suspension of gallium silylimide K [3] in benzene is exposed to N2O, no reaction is observed at room temperature. Heating this mixture at 80 °C for 3 d leads to the formation of a single new species, K2[(NON)Ga{O(SiPh3)}(N3)]2, K2[6]2 (Scheme 7), which can be isolated as a microcrystalline precipitate in 61% yield and characterised by standard spectroscopic techniques and elemental microanalysis. Single crystals can be obtained by recrystallization from benzene: in the solid state, azide complex K2[6]2 adopts a dimeric structure, closely related to that of its cyanide analogue K2 [5]2: two anionic [(NON)Ga{O(SiPh3)}(N3)] -fragments are bridged by potassium counter ions to give a centrosymmetric dimer. Both structures feature a five-coordinate gallium centre, the geometry of which lies between trigonal bipyramidal and square pyramidal (t = 0.54 for K2[6]2; 0.78 for K2 [5]2). Approximating to the trigonal pyramidal limit, both complexes feature the OSiPh3 ligand in the equatorial plane, with the CN -/N3 -ligand occupying the apical site trans to the xanthene O-donor. The Ga1-N3 distance is 1.989(2) Å, and the Ga-O2 and Ga-N1/2 distances for K2[6]2 (1.8345( ) and 1.960(2)/1.969(2) Å) are equal within error those measured for K2 [5]2 (1.8312( ) and 1.959(1)/1.965(2) Å). The N3-N4 and N4-N5 distances (1.182(3) Å and 1.152(3) Å) are typical of a terminally-bound azide ligand, and the IR spectrum of K2[6]2 shows a strong absorption band at 2127 cm -1 , which is also consistent with the N3 -ligand. The reactions of both aluminium and gallium silylimides with N2O are postulated to proceed via the formation of a transient metal oxide intermediate, together with an equivalent of silylazide. In the case of the aluminium silylimides, K[1a], K[1b] and K[1c], the (common) oxide intermediate so generated has previously been shown to undergo a [2+3] cycloaddition with further N2O to yield the observed hyponitrite product, K2[VIIIb]2. The putative gallium oxide intermediate, by contrast, would be expected to feature a less polarized Ga-O bond, and instead activates the Si-N bond of the initially generated silylazide 1,2-fashion (to generate azide, N3 -, and siloxide ligands, Ph3SiO -, at gallium). Conceptually similar 1,2-addition reactions of the N-Si bond of a silylazide across M-NR units have previously been reported, leading to the formation of metal-bound azide and silylamide ligands.