Preparation of metal carbides, nitrides, borides, silicides and phosphides, also metal alloys and pure metals, by providing a precursor in which there are organic ligands bonded to the metal or metals, such precursor having the element X also bonded directly or indirectly to the metal or metals, the ligand-metal bonding being weaker than the X-metal bonding whereby on pyrolysis the product M.sub.a X.sub.b results in which M represents the metal or metals, X represents C, N, B, Si, P and a and b represent the atomic proportions of M and X. The subscript b may be zero if an alloy or pure metal is to be prepared. The product M.sub.a x.sub.b can be prepared by relatively low temperature pyrolysis and the precursor can be used as a solution or a low melting solid. This enables one to apply a surface coating or to shape the precursor into a fiber, rod or other shape and to pyrolyze the coating or shaped article. M is a transition, lanthanide or actinide metal or tin.