An anhydrous chloride with a formula of MCl₂ (M=Fe, Co or Ni) is dissolved into an anhydrous acetonitrile solvent to form a chloride-acetonitrile solution. Then, calcium carbide minute powders are added and dispersed in the chloride-acetonitrile solution at a molar quantity equal to or smaller by 1-30 mol % than the molar quantity of the anhydrous chloride to form a reactive solution. Then, the reactive solution is heated at a predetermined temperature to chemically react the anhydrous chloride with the calcium carbide minute powders in the reactive solution to form a transition metal acetylide compound having an M-C₂-M bond, a tetragonal structure, and a formula of MC₂ (herein, M=Fe, Co or Ni).