This article deals with the different modes of preparation of alloys or intermetallic compounds using the electrodeposition in molten salts, more particularly molten alkali fluorides; the interest of this process is obtaining new materials for high technology, particularly the compounds of reactive compounds such as actinides, rare earth and refractory metals. Two ways of preparation are considered: (i) electrocoating of the more reactive metal on a cathode made of the noble one and reaction between the two metals in contact; the potential of this reaction is between the red ox potentials of each element and can be calculated from the energy of the reaction of alloy formation; the kinetic of growth of the alloy obeys to the laws of diffusion in the solid state; (ii) electrocoating on an inert cathode of the intermetallic compound by coreduction of the ions of each elements; the potential of his coreduction depends both on the content of the electrolyte in each ion and the activity of the each element in the alloy. The kinetic is controlled by the reaction at the electrolyte interface. A wide bibliographic survey on the preparation of various compounds (borides, carbides…) is given; a special attention is paid on the own experience of the authors on the preparation of these compounds and interpretation of their results.