Cobalt acetylide (CoC 2 ) is synthesized by ion exchange reaction of CaC 2 with CoCl 2 in acetonitrile under oxygen and water-free condition. CoC 2 produces carbon-skinned nano-metallic crystals. Inclusion of 20% SmCl 2 provides the particles with a larger cohesive force. Cu 2 C 2 synthesized by a reported method with some modifications produces nanowires with diameters 5–20nm. Excitation of these nano-objects by electron beam or ArF laser, or simple heating produces carbon-skinned metallic nanowires and nanocrystals stable in air.