Silicon is the second (after oxygen) most abundant chemical element on the earth: ca. 28% of the earth’s crust, mostly in the form of SiO₂ recognized as early as XVIIth century. Despite such a widespread presence, the natural resources for silicon (which does not occur naturally in its elemental form) and its derivatives (namely, silica and silicates) contain only Si–O bonds which are very strong and therefore are not very useful for making new types of silicon compounds. Accordingly, organosilanes with Si–C bonds (as the key reagents in organosilicon chemistry) are not natural chemical compounds; therefore they must be prepared synthetically in chemical laboratories and plants.

Although being the second element of group 14 in the periodic table (just below carbon), silicon in many respects is different from its lighter homologue. There are two major differences that distinguish silicon from carbon: size and electronegativity [1,2]. Silicon is substantially larger than carbon, and therefore the former exhibits a greater tendency towards higher coordination numbers (hypercoordinate compounds) than the latter. Increase in the size of silicon vs. carbon results also in longer Si–C bonds (as compared to the analogous C–C bonds), which leads to remarkably less effective bonding between the atoms. The lower electronegativity of silicon compared with that of carbon (1.8 vs. 2.5 according to the Pauling scale) results in more polar (more ionic) Si–C bonds compared with the analogous C–C bonds. Such remarkable Si^δ+–C^δ– bond polarity with the profoundly electrophilic silicon center causes the great reactivity of organosilanes.

Organosilicon chemistry, as a subfield of silicon chemistry focused on compounds with Si–C bonds, started more than a hundred years ago by the pioneering work of Friedel and Crafts who isolated Et₄Si from the reaction of Et₂Zn with SiCl₄ at 140°C [3-5]. This original discovery was further developed by the contributions of Frankland, Pape, Ladenburg and others, who synthesized new organosilanes and organochlorosilanes. However, the major breakthrough came at the very beginning of the XXth century, when Frederick Stanley Kipping, the pioneer of organosilicon chemistry, convincingly demonstrated the utility of the Grignard reaction as a general method for the preparation of organosilanes: the first paper in a series of 51 papers published in the Journal of the Chemical Society appeared in 1901 (for example: SiCl₄ + EtMgI → Et_nSiCl_4–n) [1,3-5]. The fundamental importance of Kipping’s discovery was widely recognized through the ACS Award for Organosilicon Chemistry, which is named after him. As the other milestone achievement in organosilicon chemistry, one should mention the development of the “direct process” (Si + MeCl → Me₂SiCl₂, catalyzed by copper) by Eugene Rochow and Richard Müller in 1941–1942 [1,3-5]. After that, functional organosilanes became industrially available for large-scale production.

At present, organosilicon chemistry covers a very broad field of research that ranges from bioorganic silicon chemistry to application of organosilicon compounds in material science, going throughout all aspects of synthetic molecular, macromolecular, inorganic, coordination and physical chemistries [6,7]. In the fundamental synthetic organic, inorganic and organometallic silicon chemistry, the dominating trends lie in the field of either low-valent [8] or hypervalent [9,10] derivatives. For example, in the field of low-valent organosilicon compounds, the major fields of interest are represented by the trivalent silicon centered cations, radicals and anions, divalent silylenes, and unsaturated compounds featuring multiple bonds to silicon [8]. The milestone breakthroughs achieved in this research area during the past three decades establish a fundamental basis for the following application of organosilicon chemistry in material science. Among numerous industrially important applications, one should mention production from silane monomers of the silicon-based organometallic polymers, silicones, as the novel high-value products on the chemical market throughout the world: over 10⁹ kg of silicones are produced each year [5]. Silicones are particularly attractive from the viewpoint of their high thermal and electric stability and very low surface energy that are greatly different from those of organic polymers. Thanks to their specific properties, silicones are widely used in sealants, adhesives, lubricants, medical applications, cookware and insulations. Another important field is the use of silicon derivatives in the formation of nanoporous materials, typically prepared by a sol-gel polycondensation in the presence of surfactants [6,7]. Mesoporous silica nanoparticles (such as MCM-41 and SBA-15), available by this method, have found applications in catalysis, drug delivery and medical imaging. All above-described research topics (as well as many others) were broadly discussed at the most representative silicon meeting, the International Symposium on Organosilicon Chemistry (ISOS), the last three of which being held in Würzburg, Germany, (ISOS-XIV, 2005), Jeju, Korea (ISOS-XV, 2008) and Hamilton, Canada (ISOS-XVI, 2011).

Looking to the future, one can expect further advances in the development of siloxane-based compounds for electronics, catalysis, silicon nanotubes; silicon-based materials with novel optoelectronic properties (photoluminescense, electroluminescense, etc.); hybrid polymers and dendrimers for catalysis, and coatings; zeolites for catalysis and as storage systems; silica- and SiO₂-based ceramics; silicon materials for use in communication technologies (glass fibers, etc.), and bioorganic chemistry (biologically active organosilicon compounds, biodegradation of silicones, silicone-based delivery systems, nanostructured silicone- and silica-based materials, enzymatic Si–C bond formation) [4].