“…Studies on silicon-based surface chemistry have attracted a lot of attention from the perspective of basic science. − A lot of research works have been performed for the molecular adsorption on Si surfaces, − where the various types of molecules, from simple to complex ones, are used for exploring new functions of surfaces. Several works have concerned mainly on the molecules with unpolarized CC or CC, − multiple-membered aromatics, − ,, some unsaturated cyclic hydrocarbons, ,, zwitterionic organic molecules, , and benzene and its related molecules. − ,,− The adsorption behavior of polarized molecules with CN function, the simplest nitrile of acetonitrile, was reported on Si{100}. − For acetonitrile, it was suggested in several experimental , and theoretical ,− works that a [2 + 2] cycloaddition reaction through the CN function occurred (di-σ model). The acetonitrile adsorbed molecularly on Si{100} in a di-σ configuration, holding a CN functionality, followed by further multiple reactions. − …”