The molecular Kohn-Sham exchange-correlation potential upsilon(xc) and the energy density epsilon(xc) have been constructed from ab initio first- and second-order density matrices for the series XH (X=Li, B, F). The way various effects of electronic structure and electron correlation manifest themselves in the shape of upsilon(xc) and epsilon(xc) has been analyzed by their decomposition into various components; the potential of the exchange-correlation hole, the kinetic component and (in the case of upsilon(xc)) the "response" component. The kinetic energy of noninteracting particles T-s, the kinetic part of the exchange-correlation energy T-c, and the energy of the highest occupied molecular orbital epsilon(N) have been obtained with reasonable accuracy and the effect of bond formation on these functionals has been studied.(1)