A polymeric precursor, polysiloxazane (PSON), for SiCON ceramics has been synthesized by the partial hydrolysis of MeViSiCl2, MeHSiCl2, and MeSiCl3 followed by ammonolysis reaction of the hydrolyzed intermediates with NH3. The structure and thermal properties of the polymeric precursor were investigated by means of Fourier transfer infrared spectra (FTIR), 1H-NMR, 29Si-NMR, gel permeation chromatography, and thermogravimetric analysis. The structure of the SiCON ceramics derived from the pyrolysis of PSON was characterized by FTIR and X-ray diffraction. The as-synthesized PSON produced mainly a-Si3N4 crystalline phase during pyrolysis at 1500 degrees C under N2 atmosphere, whereas when pyrolyzed at 1500 degrees C under Ar atmosphere, crystalline phases of a/beta-SiC and/or a-Si3N4 were detected. (c) 2012 Wiley Periodicals, Inc. J fAppl Polym Sci, 2012