By a novel solid-state reaction process using amorphous C3N4 (a-C3N4) and transi-tion metal oxides as starting reagents,cubic TaC,NbC and hexagonal WC nanoparticles were suc-cessfully synthesized at 1150 ℃.The products were characterized by power X-ray diffraction (XRD),field-emission scanning electron microscope (FE-SEM),energy-dispersive X-ray spectroscopy (EDX),transmission electron microscopy (TEM) and high-resolution TEM (HRTEM).The experimental re-sults show that a-C3N4 obtained by the reaction between C3N3Cl3 and Li3N is a highly efficient car-buration reagent and the transition metal oxides are completely transformed into the corresponding metal carbide nanoparticles at 1150 ℃,respectively,which is significantly lower than that reported for the traditional preparation of carbides,typically>1600 ℃.The TaC,NbC and WC nanoparticles are found to have an average particle size of 10 nm,15 nm and 8 nm by TEM observation,respectively. By a novel solid-state reaction process using amorphous C3N4 (a-C3N4) and transi-tion metal oxides as starting reagents, cubic TaC, NbC and hexagonal WC nanoparticles were suc-cessfully synthesized at 1150 ° C. The products were characterized by power X -ray diffraction (XRD), field-emission scanning electron microscope (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and high-resolution TEM (HRTEM) show that a-C3N4 was obtained by the reaction between C3N3Cl3 and Li3N is a highly efficient car-buration reagent and the transition metal oxides were completely transformed into the corresponding metal carbide nanoparticles at 1150 ° C, respectively, which is significantly lower than that reported for the conventional preparation of carbides, typically> 1600 ° C. The TaC, NbC and WC nanoparticles are found to have an average particle size of 10 nm, 15 nm and 8 nm by TEM observations, respectively.