At room temperature diluted TiCl 4 and CCl 4 were reduced by sodium particles and mixed with a polycarbomethylsilane (PCS) solution to yield a precursor. It was dried and subsequently annealed at 1300°C, 1400°C and 1450°C in a tube furnace using argon with 10ppm N 2 . After the 1450°C annealing a nanocrystalline powder of TiC 0.5 N 0.5 –SiC polyhedron and elongated crystals was obtained. At the low nitrogen concentration during annealing a gradual nitration is proposed. It is promoted by carbon gaseous species, precursor oxidation, a sufficient temperature and a summarised nitrogen surplus compared to the titanium and carbon amount.