Cobalt acetylide (CoC2) is synthesized by ion exchange reaction of CaC2 with CoCl2 in acetonitrile under oxygen and water-free condition. CoC2 produces carbon-skinned nano-metallic crystals. Inclusion of 20% SmCl2 provides the particles with a larger cohesive force. Cu2C2 synthesized by a reported method with some modifications produces nanowires with diameters 5-20 nm. Excitation of these nano-objects by electron beam or ArF laser, or simple heating produces carbon-skinned metallic nanowires and nanocrystals stable in air. (C) 2005 Elsevier B.V. All rights reserved.