**4. Conclusion**

The synthesis of new crystalline materials is a field of intense activity in solid-state chemistry. In this chapter, the most adopted methods of synthesis of the crystalline materials are described. The first part is dedicated to solid-state method, combustion reaction, hydrothermal method, sol–gel process and copreciptation method. These methods lead to different types of crystalline phase such as organic and hybrids compounds, organometallics, oxides, intermetallic alloys, etc. However, a control of several parameters such as temperature, pressure, etc. is necessary.

The second part is devoted to intermetallic compounds synthesized by arc furnace, induction furnace and high energy grinding methods.

The arc furnace is a system using electrothermal energy provided by an electric arc to heat a load. Electric arc furnaces are used almost exclusively for the manufacture of steel from scrap recovery or arcs develop between each of three electrodes in graphite and metal, this last melt by direct attack bows digging wells in the solid metal charge.

The induction furnace is an electric furnace operating thanks to the phenomenon of metal induction heating. This method presents several advantages; it is clean, energy efficient and allows better control of the metals melting. The capacities of induction furnaces vary from less than one kilogram to one hundred tons; they are used to melt iron and steel, copper, aluminum and precious metals.

Mechanosynthesis is a very high energy milling technique, which allows to obtain metastable crystalline or nanocrystalline phases and to transform crystalline phases into amorphous phases.

*Crystallization and Applications*
