The density functional theory is used to explore alkylthiolates (RS) bonded to Au(111) and gold adatoms on Au(111). Adsorption of RS to adatoms in a structure characterized as an (RSAu)(x) polymer is strongly preferred over terrace adsorption. The energetic gain upon polymerization is large enough to drive the required Au(111) reconstruction. The results are discussed in relation to thiolate protected gold nanoparticles and homoleptic gold- thiolate complexes.