A stable silicon analogue of an acid anhydride {PhC(Bu(t)N)(2)}Si{=O center dot B(C(6)F(5))(3)}O-Si(H){=O center dot B(C(6)F(5))(3)}{(NBu(t))(HNBu(t))CPh} (4) with a O=Si-O-Si=O core has been prepared by treating monochlorosilylene PhC(Bu(t)N)(2)SiCl (1) with H(2)O center dot B(C(6)F(5))(3) in the presence of NHC (NHC = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene). Compound 4 has been characterized by elemental analysis and multinuclear NMR spectroscopic investigations. The molecular structure of 4 has been established by single-crystal X-ray diffraction studies, and DFT calculations support the experimental results.