clearly demonstrated. Compared to analogous hypochlorites, these fluoroxy compounds give only low yields of addition products with fluorinated olefins due to the rapid decomposition of the intermediate OCF2CFXSO2F radicals formed in these reactions.Acknowledgment. The partial financial support of this research by the National Science Foundation and the Gas Research In-stitute (Grant 5084-260-1086) is gratefully acknowledged.

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The synthesis of hypervalent tris(catecho1ato)silicate ion, f(C6H402)3Si12~~ with six different counter cations: (i) diethylammonium (I), (ii) triethylammonium (II), (iii) diisopropylammonium (III), (iv) morpholinium (IV), (v) piperazinium (V) and (vi) N-methylpiperazinium (VI) has been achieved (yield: ~~7.95%) by the reaction of catechol and tetraethoxysilane in presence of the corresponding amine. Single crystal X-ray structure of compound ( 111) has been determined. It crystallizes in orthorhombic system [space group P2,2121; n = 11.735(2), b = 13.708(3), c = 23.283(5) A; 01 = 90", ,!!= 90"' -y = 90"; Volume = 3745.4(11) A3; Density = 1.165 gcni-3; Z = 4; X = 0.0585; wR2(I) = 0.1610 and 3677 reflections] and the structure shows slightly distorted octahedral geometry around silicon. Results of TG, DT and EG analysis of compounds (I) -(VI) reveal the influence of the counter cation on thermal stability. Bench scale pyrolysis of (I) and (11) convert them to [(ChH402)2Si],I by the quantitative expulsion of ammonium catecholate salt, (M')2[(ChH402)12-. CP-MAS 29Si-nmr spectral data suggests that [(ChH402)2Si]iI is a simple mixture.

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