A comparative theoretical study was made of single-monolayer coverages of group-V elements (P, As, Sb, Bi) on the Si(001) surface. The generic 2 x 1 surface reconstruction, due to the formation of symmetrical overlayer dimers, was considered and a first-principles pseudopotential method was used. In addition to presenting well-relaxed structural data, chemical trends in geometry, bonding and electronic structure were identified on moving down the group-V column. Overlayer-induced distortion of the substrate was found to decrease with increasing overlayer atomic number. In general, P and As overlayer systems shared many similarities, while Sb and Bi formed another analogous pair. A novel feature of group-V overlayers was that the bonding and occupied antibonding states formed by the dangling bonds were very close in energy. Comparative ab initio Pseudopotential Studies of (2 x 1) Group V Overlayers on Si(001). S.C.A.Gay, S.J.Jenkins, G.P.Srivastava: Journal of Physics - Condensed Matter, 1998, 10[35], 7751-68